ASE B3 Glossary — 591 Non-Structural Analysis and Damage Repair Terms & Definitions

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A

Access HoleOuter Body Panel Repairs and Replacements: An access hole is an opening that lets a technician reach fasteners and other components located inside a door.
AcetyleneWelding, Cutting and Removal: Acetylene is a fuel gas used in flame welding and flame cutting operations.
Acid Core SolderMetal Finishing and Body Filling: Acid core solder is solder in tubular wire form with an acid flux paste contained inside the core of the wire.
Active GasWelding, Cutting and Removal: An active gas is a gas such as oxygen that will react with other substances, as opposed to an inert gas that will not.
AdapterOuter Body Panel Repairs and Replacements: An adapter is a fitting or accessory that connects two components of different sizes, types, or connection standards - commonly used in body repair to allow standard tools to fit non-standard fasteners or to attach accessories to air tools and spray equipment.
Adhesion PromoterSurface Preparation: An adhesion promoter is a chemical pre-treatment applied to difficult-to-bond substrates - particularly plastics, aluminum, and previously painted surfaces - to chemically activate the surface and improve the mechanical and chemical bond of subsequent primer and paint layers.
Adhesive Backed MoldingGlass and Hardware: An adhesive backed molding is a trim piece supplied with an adhesive coating already applied to its back to simplify installation.
Adhesive Primer/HardenerGlass and Hardware: Adhesive primer/hardener is a material brushed onto a mirror support and onto the glass before the mirror mounting adhesive is applied.
AdhesivesOuter Body Panel Repairs and Replacements: Structural adhesives in collision repair are two-part epoxy or urethane compounds used to bond body panels - often in combination with spot welds (weld-bond technique) - to increase structural rigidity, improve corrosion protection at weld seams, and damp noise and vibration.
Adjustable WrenchOuter Body Panel Repairs and Replacements: An adjustable wrench is a hand tool with a fixed jaw and a threaded worm-gear-adjusted movable jaw that can be set to grip a range of different-sized hex, square, or flat fasteners without the need to select a different wrench for each size.
Adjusting SlotOuter Body Panel Repairs and Replacements: An adjusting slot is an elongated hole on a mounting bracket or bumper shock absorber that permits alignment adjustment during installation.
Aftermarket Replacement PanelsOuter Body Panel Repairs and Replacements: Aftermarket replacement panels are body panels manufactured by companies other than the original vehicle maker, sold at a lower price than OEM panels but potentially requiring additional fit and finish work to achieve proper panel gaps and contour match.
Aiming ScrewOuter Body Panel Repairs and Replacements: Aiming screws are the adjusting screws used to aim a headlight.
Air DamOuter Body Panel Repairs and Replacements: An air dam is the structure mounted under the front portion of a vehicle that directs air through the radiator and across the engine.
Air DrillSurface Preparation: An air drill is a pneumatically powered rotary tool used in collision repair for drilling holes, driving fasteners, removing decals with eraser wheels, and operating grinding or cutting accessories - offering lighter weight, higher RPM, and longer continuous run capability than comparable electric drills.
Air FileMetal Finishing and Body Filling: An air file is a pneumatic body shop tool with an elongated, flat sanding pad that moves in a straight, back-and-forth stroke, designed to sand and level body filler or primer across large, flat panel areas more accurately and consistently than hand sanding or orbital sanders.
Air LeaksOuter Body Panel Repairs and Replacements: A whistling or hissing noise inside the passenger compartment caused by air passing through a gap in the body seals, weatherstripping, or hardware while the vehicle is being driven.
Air Pressure RegulatorSpray Gun Operation: An air pressure regulator is a pneumatic device installed in the compressed air supply line that reduces high compressor tank pressure to a lower, adjustable working pressure and automatically holds that pressure steady regardless of fluctuations in the main air supply.
Air RatchetOuter Body Panel Repairs and Replacements: An air ratchet is a pneumatic hand tool that combines the compact form of a hand ratchet with air-powered rotation, allowing fast removal and installation of fasteners in confined spaces where a standard impact wrench or hand ratchet is too large or too slow.
Air SanderSurface Preparation: An air sander is a pneumatically powered abrasive tool used in collision repair and paint preparation to strip old finish, level body filler, scuff primers, and sand repaired surfaces - available in dual-action (DA), straight-line, and rotary configurations for different stages of surface preparation.
Air Supply SystemSafety Precautions: An air supply system is an air pumping system that supplies fresh breathing air to a painter working in a paint spray booth.
Air-Supplied RespiratorSafety Precautions: An air-supplied respirator is a personal protective equipment device that delivers clean, breathable air to the wearer from an external compressor or air tank through a hood or mask - required when spraying isocyanate-containing paints or other toxic materials that exceed the protection capability of a standard filter respirator.
AlignOuter Body Panel Repairs and Replacements: To bring two or more body panels, components, or structural members into their designed positional relationship - even gaps, flush surfaces, and correct fit - as the standard against which all panel replacement and adjustment work is evaluated.
Aligning PunchOuter Body Panel Repairs and Replacements: An aligning punch is a long, tapered steel hand tool used to align panel flanges, mounting holes, and bolt holes during panel replacement or assembly by inserting the tapered tip into misaligned holes and twisting or prying to bring them into register before fasteners are installed.
Allen WrenchMetal Finishing and Body Filling: An Allen wrench (hex key) is a hexagonal, six-sided hand tool used to drive fasteners with a matching hexagonal recess.
AlloyVehicle Systems Knowledge: An alloy is a mixture of two or more metals.
Aluminum Electrode WireWelding, Cutting and Removal: Aluminum filler wire used as the electrode in aluminum GMAW welding, classified into alloy series based on the metals the aluminum is alloyed with.
American National Standards Institute (ANSI)Safety Precautions: The organization whose standards, such as Z87.1 for eye protection, set the certification requirements for safety equipment used in shops nationwide.
American Welding Society (AWS)Welding, Cutting and Removal: The organization that publishes formal welding process names and electrode classification codes used throughout the industry, such as GMAW (the formal name for MIG) and the EWP tungsten electrode code.
Anti-seize CompoundVehicle Systems Knowledge: A metallic-paste thread lubricant (typically aluminum, copper, or nickel-based) applied to fastener threads before installation to prevent galvanic corrosion, galling, and thread seizure - ensuring the fastener can be removed without damage even after extended exposure to heat and corrosive environments.
Anticorrosion MaterialsOuter Body Panel Repairs and Replacements: Anticorrosion materials are protective compounds - including weld-through primer, sealers, rubberized undercoating, and corrosion-inhibiting coatings - applied to bare metal surfaces during and after collision repair to prevent rust formation and restore the factory corrosion protection that was damaged in the repair process.
Antilacerative GlassGlass and Hardware: Antilacerative glass is a type of laminated automotive safety glass with one or more additional plastic layers bonded to the interior (passenger-facing) surface, designed to prevent glass fragments from cutting occupants during a collision by keeping broken pieces adhered to the plastic backing.
Aqueous Film Forming Foam (AFFF)Safety Precautions: A fire-extinguishing foam that seals the surface of a flammable liquid fire, cutting off oxygen and preventing re-ignition.
AsbestosSafety Precautions: Asbestos is a cancer-causing material once used in the manufacture of brake and clutch linings.
Asbestos DustSafety Precautions: Asbestos dust is a hazardous particulate released when brake pads, clutch discs, or gaskets containing asbestos fibers are disturbed - a known carcinogen that must never be blown with compressed air but instead removed with a HEPA vacuum or wet method to prevent inhalation.
ASE CertificationLegal and Environmental Practices: ASE certification is a voluntary testing program that provides recognition that a person is a knowledgeable collision repair technician or estimator.
AssemblyVehicle Systems Knowledge: An assembly is two or more parts bolted or welded together to form a single unit -- several parts put together before the whole is attached.
Automated External Defibrillator (AED)Safety Precautions: A shop safety device that delivers a controlled shock to the heart during cardiac emergencies; its adhesive pads require bare, dry skin contact and its voice prompts must be followed exactly.
Automotive Service Association (ASA)Legal and Environmental Practices: ASA is a national automotive service industry association, listed in the source material among the organizations serving the collision repair and automotive service trades.

B

Backing StripWelding, Cutting and Removal: A backing strip is a reinforcing patch placed behind a joint to support and strengthen a weld, such as a butt weld with backing.
Ball Peen HammerOuter Body Panel Repairs and Replacements: The ball peen hammer is a steel-headed hand tool with one flat face and one hemispherical (ball) face, used in collision repair for rough-shaping heavy gauge metal, straightening frame and structural components, and general mechanical work - it is heavier and more robust than a finishing body hammer.
Barrier CreamSafety Precautions: Barrier cream is a hand cream that provides protection and soothes the skin when working with irritating materials.
Base MetalWelding, Cutting and Removal: Base metal is any metal that is to be welded or cut.
Bathtub ClipGlass and Hardware: Bathtub clips are small plastic attachment pieces pressed into holes in the vehicle body, to which moldings are attached.
Belt LineOuter Body Panel Repairs and Replacements: The belt line is the horizontal molding or crown running along the side of the vehicle at the bottom of the glass.
Belt Trim Support RetainersGlass and Hardware: Belt trim support retainers are the parts that hold door window glass in position and prevent it from wobbling.
Bench GrinderMetal Finishing and Body Filling: A bench grinder is a tool bolted to a workbench and driven by an electric motor, used with abrasive wheels or discs for sharpening, heavy-duty grinding, deburring, and smoothing.
BendMetal Finishing and Body Filling: A type of sheet metal deformation characterized by a smooth, gradual transition between the damaged and undamaged areas - unlike a kink or crease, a bend retains the metal's structural integrity and can be straightened by applying force in the opposite direction without tearing or work-hardening the metal beyond repair.
BezelGlass and Hardware: A bezel is a trim ring that surrounds a headlight or a gauge.
Bodied CementPlastic Repair: Bodied cement is a syrupy solvent cement composed of a solvent plus a small quantity of compatible plastic, used to bond plastic parts.
Body FileMetal Finishing and Body Filling: A body file is a flat, half-round, or round file designed to be pushed across the work surface in the direction of the cutting teeth.
Body FillerMetal Finishing and Body Filling: Body filler is a two-part polyester compound mixed with a hardener that chemically cures to a rigid, sandable material used to fill minor surface irregularities, low spots, and small dents in metal or plastic panels - it is applied over properly prepared bare metal and sanded to restore the panel's original contour before priming.
Body GapsOuter Body Panel Repairs and Replacements: Body gaps indicate panel misalignment resulting from structural damage, shifted panel fasteners, or worn mechanical parts.
Body HammerMetal Finishing and Body Filling: A body hammer is a specialized hammer used to reshape damaged sheet metal.
Body JackOuter Body Panel Repairs and Replacements: A body jack is a portable hydraulic pushing and pulling tool - sold in sets with various extension bars, rams, and attachments - used to push out dents, realign body panels, spread or compress structural members, and perform limited straightening of body and structural damage.
Body Line Sanding GuideMetal Finishing and Body Filling: A body line sanding guide is a specialized sanding tool with an adjustable framework that mounts on the panel and guides the sandpaper exactly along the contour of a character line or body line, ensuring the sharp, precise line is sanded perfectly straight without rounding or losing definition.
Body SawWelding, Cutting and Removal: A body saw is a saw fitted with an abrasive blade, used to cut floor sections or panels.
Body ShimOuter Body Panel Repairs and Replacements: A body shim is a thin metal or plastic spacer inserted between a body panel and its mounting bracket or frame attachment point to fine-tune the panel's position, correct uneven gaps, and achieve proper alignment with adjacent panels during installation or repair.
Body SolderMetal Finishing and Body Filling: Body solder is an alloy of tin and lead -- sometimes including antimony or silver -- melted to fill dents and other defects in metal body panels.
Body SpoonsOuter Body Panel Repairs and Replacements: Body spoons are long-handled, flat-faced metal tools used in bodywork as either a slapping tool (to move large low areas with controlled force) or as an access dolly (slipped behind a panel to back up hammer strikes in areas where a conventional dolly cannot reach).
Body TechnicianOuter Body Panel Repairs and Replacements: A body technician is a person who performs basic collision repair tasks such as removing dents, replacing damaged parts, welding metal, filling, sectioning, and sanding.
Bolt Grade MarkingsOuter Body Panel Repairs and Replacements: Bolt grade markings are the lines (SAE) or numbers (metric property class) stamped or raised on the top of a bolt head that identify the bolt's tensile strength and hardness, indicating how much clamping force and torque it is designed to withstand.
Bolt-Through GlassGlass and Hardware: Bolt-through glass is glass held to the regulator mechanism with mechanical fasteners such as bolts or rivets.
Bonding StripsMetal Finishing and Body Filling: Bonding strips are strips of aluminum, fiberglass, or aluminum-and-stainless-steel tape used to patch holes in vehicle bodies.
Box-End WrenchOuter Body Panel Repairs and Replacements: A box-end wrench is a hand tool with a fully enclosed ring-shaped head that completely surrounds a hex or square fastener and contacts all six points, providing stronger and more secure grip than an open-end wrench - especially on tight or rounded fasteners.
BracketsVehicle Systems Knowledge: A bracket is a part used to attach components to each other, or to attach a component to the body or frame.
Braze WeldingWelding, Cutting and Removal: Braze welding is a method of welding using a filler metal, performed and controlled by hand.
BrazingWelding, Cutting and Removal: Brazing is a metal-joining process in which a filler metal with a lower melting point than the base metals is melted and flowed into the joint by capillary action, bonding the base metals without melting them - producing a strong joint used in automotive applications for thin-gauge panels and MIG brazing of galvanized steel.
Breaker BarOuter Body Panel Repairs and Replacements: A breaker bar is a long, rigid, non-ratcheting drive handle that accepts standard sockets and provides maximum torque leverage for breaking loose heavily torqued, corroded, or seized fasteners that a standard ratchet handle cannot budge.
Brushable Seam SealersWelding, Cutting and Removal: Brushable seam sealers are thick, paintable compounds applied by brush to interior weld seams and panel joints that are hidden from view, sealing them against moisture, dirt, and road contamination to prevent corrosion in areas where a cosmetic finish is not required.
BucklesMetal Finishing and Body Filling: Buckles are the distortions, ridges, or high places that appear in a metal body part as a result of collision damage -- deformation caused when metal is bent beyond its elastic limit and will not return to its original shape.
BulgeMetal Finishing and Body Filling: A bulge is a high crown or an area of stretched metal standing above the panel's normal contour.
Bull's-EyeMetal Finishing and Body Filling: A bull's-eye is a circular surface depression that forms over a repair area when body filler or primer-surfacer shrinks after being sanded prematurely or applied with improper featheredging.
Bull's-Eye FeatheredgeFinish Defects, Causes and Cures: A bull's-eye featheredge is a paint defect appearing as a circular ring or depression in the finish coat, caused by shrinkage of the spot putty or body filler underneath - the filler or putty contracts after painting, pulling the topcoat down into the shape of a bull's-eye around the repair area.
Bumper ReinforcementsOuter Body Panel Repairs and Replacements: The structural beam or bar mounted between the bumper fascia and the vehicle's frame or bumper brackets that provides the primary impact absorption and load distribution during a low-speed collision - protecting the vehicle structure from damage that the flexible fascia alone cannot resist.
BumpingMetal Finishing and Body Filling: Bumping is the process of smoothing a damaged area after roughing out has been completed.
Bumping HammerOuter Body Panel Repairs and Replacements: A bumping hammer is a wide, relatively flat-faced body hammer used to move large, shallow dents by distributing the striking force over a broad area, reducing the risk of creating additional high spots or stretched metal while roughing out damaged panels.
Burn MarkWelding, Cutting and Removal: A burn mark found on the back of a weld is an indication of good weld penetration -- the term also describes a mark left on paint by improper technique.
Burn-ThroughWelding, Cutting and Removal: Burn-through is a welding defect in which excessive heat or amperage causes the welding arc to melt completely through the base metal, creating a hole in the panel - the result of too much heat input, too slow a travel speed, or incorrect settings for the metal thickness being welded.
Butt JointWelding, Cutting and Removal: A weld joint configuration in which two panel edges are positioned end-to-end in the same plane and welded along the seam - used in sectioning repairs and panel replacement when a lap joint or flange joint is not practical; requires precise gap control and backing to achieve full-penetration weld integrity.
Butt WeldWelding, Cutting and Removal: A butt weld is a weld made along a line where two pieces of metal are placed edge to edge.

C

C-ClampPreparation: A C-clamp is used to hold parts together during assembly or welding procedures.
Caged PlateVehicle Systems Knowledge: A caged plate is a heavy, thick steel plate with threaded holes that accept large bolts.
Caged Plate AssemblyOuter Body Panel Repairs and Replacements: A caged plate assembly is a tapped plate held inside a sheet metal box that is spot welded inside a door or pillar to accept hinge and striker bolts, with the plate able to move within its cage to allow adjustment.
California Air Resources Board (CARB)Legal and Environmental Practices: California's state environmental agency that regulates vehicle and refinish-product emissions, working alongside the federal EPA.
CAMI Grit Grading SystemMetal Finishing and Body Filling: The United States sandpaper grit grading standard, one of several systems (alongside FEPA P-grade) manufacturers may use to rate abrasive coarseness.
CanisterSafety Precautions: A canister is a container of chemicals designed to remove specific vapors and gases from breathing air -- for example a container filled with charcoal.
Carbonizing FlameWelding, Cutting and Removal: A carbonizing flame is a welding flame with excess acetylene, which introduces carbon into the molten metal.
Carburizing FlameWelding, Cutting and Removal: A carburizing flame (also called a reducing or surplus flame) is an oxyacetylene welding flame produced by using more acetylene than oxygen, characterized by three distinct zones - the inner cone, a light-colored acetylene feather, and an outer envelope - used for welding aluminum, nickel alloys, and in some brazing applications.
CarcinogensSafety Precautions: Carcinogens are cancer-causing agents.
CarpetGlass and Hardware: Carpet is the floor covering used in vehicles.
CarpetingGlass and Hardware: Carpeting in collision repair refers to the molded fabric floor covering inside the vehicle passenger compartment that must be removed to access and repair floor pan damage, inspect seat belt anchor points, and restore the vehicle to pre-accident interior condition.
Cartridge Filter RespiratorSafety Precautions: A cartridge filter respirator protects against vapors and spray mists given off by one-part enamels or lacquers, and is used in well-ventilated areas.
Cartridge RespiratorSafety Precautions: A cartridge respirator is a functioning, properly fitted respirator with replaceable cartridges and prefilters that protects a painter from uncatalyzed paint.
Cavity WaxPreparation: A wax-based material sprayed into enclosed body cavities - doors, rocker panels, and pillars - to prevent internal corrosion after repairs that disturb factory-applied protection.
Center PunchesOuter Body Panel Repairs and Replacements: Center punches are hardened steel tools with a sharp, conical tip used to create a small indentation in metal that marks a reference position on a part before removal or provides a starting divot that guides a drill bit to start precisely without walking across the metal surface.
Chemical BurnSafety Precautions: A chemical burn is an injury that results when a corrosive chemical strikes the skin or eye.
Chemical BurnsSafety Precautions: Chemical burns are severe skin or eye injuries caused by contact with corrosive shop chemicals such as paint removers and parts cleaners.
Chemical Paint RemoverSurface Preparation: Chemical paint remover is a caustic, solvent-based or acid-based compound applied to painted surfaces to chemically break down and lift paint coatings - requiring full personal protective equipment (full face shield and chemical-resistant gloves) due to its ability to cause severe chemical burns on skin and eyes.
ChiselOuter Body Panel Repairs and Replacements: A chisel is a hardened steel hand tool with a beveled cutting edge, struck with a ball peen hammer to cut through spot welds, split panel flanges, separate adhesive bonds, or cut off bolt heads during collision repair disassembly operations.
Chronic EffectSafety Precautions: A chronic effect is an adverse effect on a human or animal with symptoms that develop slowly over a long period of time, or that recur frequently.
Clean Air ActLegal and Environmental Practices: The federal law that prohibits venting refrigerant into the atmosphere and requires certified recovery equipment before opening any charged A/C component.
ClearanceOuter Body Panel Repairs and Replacements: Clearance is the amount of space between adjacent parts or panels.
Clip PullersOuter Body Panel Repairs and Replacements: Clip pullers are specialized hand tools designed to reach behind interior door panels, trim pieces, and upholstery to release or remove the spring clips, u-clips, and Christmas tree fasteners that hold trim panels to the vehicle body without breaking the clips or damaging the panel.
Clip Removal ToolOuter Body Panel Repairs and Replacements: A clip removal tool is a hand tool used for removing the mechanical fasteners that attach door handles and trim.
Cold KnifeGlass and Hardware: A cold knife is a device used to cut through the adhesive that secures fixed glass or other components -- so called because it cuts without heat, unlike an electrically heated tool.
Cold ShrinkMetal Finishing and Body Filling: Cold shrinking is a metal finishing technique that uses hammer-and-dolly work (rather than heat) to shrink a stretched panel area back to its proper contour.
Cold WorkingMetal Finishing and Body Filling: Cold working is the working of metal without the application of heat.
Combination PliersVehicle Systems Knowledge: Combination pliers are the most common type of pliers, with both flat and curved gripping surfaces and two jaw-opening positions.
Combination WrenchOuter Body Panel Repairs and Replacements: A combination wrench is a hand tool with an open-end jaw on one end and a matching-size box-end (closed ring) on the other, providing both wrenching options in one tool - use the box end for initial breaking loose and final tightening, the open end for fast spinning in confined spaces.
CompositePlastic Repair: A composite is a plastic formed by combining two or more materials -- typically a polymer resin matrix and a reinforcement material such as fibers, often built up in several bonded layers.
Compressed Air Supply SystemSpray Gun Operation: The compressed air supply system is the complete network of components - compressor, storage tank, distribution lines, filters, moisture separators, and pressure regulators - that generates, conditions, stores, and delivers clean, dry, regulated compressed air to all spray guns and pneumatic tools throughout the collision repair facility.
Compressor Air TankSpray Gun Operation: The compressor air tank (air receiver) is the heavy-gauge steel cylindrical storage vessel that holds compressed air between compressor cycles, acting as a buffer to meet peak demand, allowing moisture to condense and settle for draining, and reducing pressure fluctuations at spray guns and air tools.
Compressor Drain ValveSpray Gun Operation: The compressor drain valve is the valve located at the lowest point of the compressor air tank that is opened daily to discharge accumulated water condensation and contaminant sludge, preventing internal tank corrosion, moisture contamination of air lines, and degraded paint and tool performance.
Compressor Oil PlugsSpray Gun Operation: Compressor oil plugs are the fill plug and drain plug on a reciprocating air compressor pump crankcase that provide access for checking, adding, and replacing the pump lubrication oil at manufacturer-specified service intervals.
Computer Based Testing (CBT)Legal and Environmental Practices: Computer Based Testing, or CBT, is the delivery of the certification test on a computer rather than on paper, with the advantage that the candidate receives test results immediately.
ConcaveMetal Finishing and Body Filling: Concave describes an inward curve, like a dent.
ConsoleGlass and Hardware: A console is the unit located between the bucket seats holding the gear shift mechanism, electric controls, and a lid with a storage compartment.
Consumable ElectrodeWelding, Cutting and Removal: A consumable electrode is one that also serves as the filler material -- it melts into the joint and becomes part of the weld.
Contact Tip Burn-BackWelding, Cutting and Removal: Contact tip burn-back is a GMAW welding fault where the wire melts back and fuses to the contact tip instead of feeding through normally, stopping the weld and requiring an adjustment to prevent recurrence.
Continuous WeldWelding, Cutting and Removal: A continuous weld is a weld made with the pieces of metal positioned edge to edge, forming one uninterrupted seam along the entire joint rather than a series of separated spot or stitch welds.
Contour Sanding StickMetal Finishing and Body Filling: A contour sanding stick is a shaped sanding block with a specific profile - curved, angled, or tapered - that matches the contour of a body panel or repair area, ensuring that sandpaper follows the panel's surface evenly during body filler sanding without creating flat spots or rounding panel edges.
ContractLegal and Environmental Practices: A contract is an agreement in the form of a written legal document between two or more people.
Contractual and Warranty ObligationsLegal and Environmental Practices: Contractual and warranty obligations are the legal commitments a shop must recognize and honor, arising from repair contracts with customers and from manufacturer or shop warranty terms.
Control of Substances Hazardous to Health (COSHH)Safety Precautions: The UK regulations governing hazardous substance handling, which make respiratory protection mandatory in body shop operations even when ventilation is provided.
Copper (Cu)Vehicle Systems Knowledge: Copper is a metal that is a difficult substrate to paint, and is also used in the manufacture of pigments and dryers.
Corner JointWelding, Cutting and Removal: A corner joint is a joint between workpieces meeting at right angles to form an L shape.
Corporate Average Fuel Economy (CAFE)Legal and Environmental Practices: The U.S. federal fuel economy standard that requires each vehicle manufacturer to achieve a specified average fuel economy across its entire fleet of passenger vehicles.
CorrosionPreparation: Corrosion is the electrochemical deterioration of metal - primarily steel - through oxidation reactions with moisture and oxygen that convert iron into iron oxide (rust), progressively weakening and eventually destroying the metal unless prevented or treated.
Corrosion PreventionPreparation: Corrosion prevention in collision repair is the systematic restoration of all factory-applied anti-corrosion materials and coatings - epoxy primer, weld-through primer, seam sealers, underbody coatings, and cavity wax - to any area where bare metal was exposed during structural or body repair.
Corrosion ProtectionOuter Body Panel Repairs and Replacements: The complete layered system of materials and procedures - galvanized steel, e-coat primer, seam sealers, undercoating, and cavity wax - used to prevent premature rusting of a vehicle body, every layer of which must be fully restored during collision repair.
Cosmetic RepairPlastic Repair: A cosmetic repair is a single-sided adhesively bonded plastic repair intended to restore appearance rather than full structural strength, as distinct from a double-sided bonded repair.
CouplingSpray Gun Operation: A coupling is a quick-disconnect fitting - male plug on one side, female body on the other - used to connect and disconnect air hoses, spray guns, and pneumatic tools to the shop's compressed air supply system rapidly without wrenches or tools.
CranePreparation: A crane is a portable device used to lift or move heavy objects, such as a vehicle engine.
Crater-Filling FunctionWelding, Cutting and Removal: The crater-filling function is an automatic welder feature that gradually tapers off current at the end of a weld to prevent the crater, cracking, or cratering that aluminum's rapid solidification and shrinkage can otherwise cause.
Cream HardenersMetal Finishing and Body Filling: Cream hardener is the organic peroxide catalyst (curing agent) supplied in a tube that is mixed with polyester body filler to initiate the chemical cross-linking reaction, causing the filler to harden - with correct mixing ratio critical to achieving proper cure rate, sandability, and long-term adhesion.
CreeperSafety Precautions: A creeper is a low platform on four caster rollers that a technician lies on for mobility when working under a vehicle.
CrownMetal Finishing and Body Filling: A crown is a convex curve or line in a body panel.
Cubic Feet per Hour (CFH)Welding, Cutting and Removal: The unit used to measure and set shielding gas flow rate on a welding flow meter.
Cyanoacrylate Adhesive SystemPlastic Repair: A cyanoacrylate adhesive system is a two-part adhesive that forms an extremely strong bond on hard plastics and similar materials.

D

DC Reverse PolarityWelding, Cutting and Removal: DC reverse polarity (DCEP - Direct Current Electrode Positive) is the MIG welding current configuration in which the welding wire is connected to the positive terminal and the workpiece to the negative terminal, concentrating heat at the wire tip to produce a stable arc, smooth spatter, and proper fusion in thin automotive steel.
Dead Blow HammerOuter Body Panel Repairs and Replacements: A dead blow hammer is a body hammer with a hollow head partially filled with lead shot or fine sand that shifts forward on impact to eliminate rebound, allowing the technician to deliver controlled, non-bouncing blows to soft dents and delicate panel areas without the hammer bouncing back and creating additional damage.
Deep SocketsOuter Body Panel Repairs and Replacements: Deep sockets are drive sockets with an extended cylindrical body that allows them to fit over protruding bolt stems, long studs, and recessed fasteners that a standard (shallow) socket cannot reach because the bolt extends too far through the nut.
Department Of Labor (DOL)Legal and Environmental Practices: DOL is the abbreviation for the U.S. Department of Labor.
DepressionMetal Finishing and Body Filling: A depression is a concave dent -- an area of a panel pushed inward below its normal contour.
Destructive TestWelding, Cutting and Removal: A destructive test is a weld-quality check performed on a sample piece of the same metal and thickness as the actual repair, deliberately breaking the weld apart to inspect how cleanly it separates and confirm the weld process is sound before welding the real panel.
Destructive TestingWelding, Cutting and Removal: Destructive testing is a weld quality evaluation method in which a test weld is physically destroyed by prying, hammering, or sectioning to examine its internal structure, penetration, fusion, and strength - confirming that the machine settings, technique, and material used produce acceptable welds before production repairs begin.
DieVehicle Systems Knowledge: A die is a cutting tool used to make external threads or to restore damaged threads.
DingingMetal Finishing and Body Filling: Dinging is the process of using a body hammer and a dolly to remove minor dents.
Direct Current Electrode Negative (DCEN)Welding, Cutting and Removal: A welding machine polarity setting, also called straight polarity, that keeps the electrode relatively cool and produces a pointed tip rather than a ball.
Direct Current Electrode Positive (DCEP)Welding, Cutting and Removal: A welding machine polarity setting, the opposite of DCEN, used for specific welding applications rather than for balling a pure tungsten electrode.
DollyOuter Body Panel Repairs and Replacements: A dolly is a small, heavy, contoured steel block held behind a damaged sheet metal panel to serve as an anvil during hammer work - supporting the metal from behind while hammer blows work out dents, maintaining panel shape and preventing the surrounding metal from distorting.
Dolly BlockMetal Finishing and Body Filling: A dolly block is an anvil-like metal hand tool held on one side of a dented panel while the other side is struck with a dinging hammer.
Door Dust CoverGlass and Hardware: A door dust cover fits between the inner trim panel and the door frame to keep out wind noise.
Door FrameOuter Body Panel Repairs and Replacements: The door frame is the main steel frame of the door, on which other parts -- hinges, glass, and handle -- are mounted.
Door Hinge CheckOuter Body Panel Repairs and Replacements: A door hinge check is a test that moves the door assembly up and down on its hinges to assess wear.
Door LatchOuter Body Panel Repairs and Replacements: The door latch is the spring-loaded mechanical mechanism mounted in the door edge that engages the body-mounted door striker to hold the door securely closed - with the latch release actuated by the inner and outer door handles through linkage rods, and door lock pins preventing release when locked.
Door Lock StrikerGlass and Hardware: The door lock striker is the part of a door lock assembly that the latching mechanism engages when the door is closed.
Door SagOuter Body Panel Repairs and Replacements: A condition where the rear (latch-side) edge of a door has dropped out of alignment, most often from worn or damaged hinges, causing uneven panel gaps and difficulty latching.
Door SaggingOuter Body Panel Repairs and Replacements: Door sagging is a door alignment defect in which the rear of the door drops lower than the front - causing tapered door gaps, difficult latch engagement, and contact between the door bottom and rocker panel - caused by worn hinge pins, bent hinges, loose hinge mounting bolts, or structural collision damage to the hinge pillar.
Door SkinOuter Body Panel Repairs and Replacements: The door skin is the outer door panel -- the outer panel over the door frame, clinched to the pinch weld flange.
Door Trim PanelsGlass and Hardware: Door trim panels are the padded interior facing assemblies that cover the inside surface of each door - containing armrests, power switch pods, map pockets, and speaker grilles - which must be removed to access interior door hardware, window regulators, wiring, and the cavity for repair or component replacement.
Door WeatherstrippingGlass and Hardware: Door weatherstripping is the resilient rubber or foam seal installed around the door perimeter or door opening that compresses when the door closes - sealing the gap between door and body to prevent water intrusion, wind noise, dust entry, and exhaust gas infiltration into the passenger compartment.
Drain HoleOuter Body Panel Repairs and Replacements: A drain hole is a hole in the bottom of a door, rocker panel, or other component that allows water to drain out.
Drain HosesGlass and Hardware: Drain hoses are flexible tubes connected to the sunroof drain plate that channel rainwater and condensation collected at the sunroof opening down through the body structure and out through drain exits at the lower body pillars or rocker panels, preventing water infiltration into the passenger compartment.
Drain PlateGlass and Hardware: The drain plate is the perimeter water collection tray built into the sunroof frame assembly that captures any water infiltrating past the sunroof glass seal - directing it to the corner drain hoses for routing through the pillar structure and out of the vehicle.
Drift PunchVehicle Systems Knowledge: A drift punch is a tool with a long tapered shaft and a flat tip, used to align holes.
DrillMetal Finishing and Body Filling: A drill is a power tool with interchangeable cutting bits used to bore holes.
Drill BitMetal Finishing and Body Filling: A drill bit is a cutting tool used with a drill to bore holes.
Drill PressMetal Finishing and Body Filling: A floor- or bench-mounted power drill used to bore accurate, repeatable holes in metal and other shop materials.
Drip MoldingGlass and Hardware: Drip molding is the metal molding that serves as a rain gutter over the doors -- also called a drip cap.
Drive SizesVehicle Systems Knowledge: Drive sizes are the fractional sizes of the drive post on sockets -- 1/4, 3/8, 1/2, and 3/4 inch -- with smaller drive sizes used for lighter work such as electrical fasteners.
Dust RespiratorSafety Precautions: A dust respirator is a disposable paper or cloth filter mask worn over the nose and mouth to block harmful airborne particles generated by sanding, grinding, and blowing off panels.
Dye PenetrantMetal Finishing and Body Filling: Dye penetrant is a liquid inspection chemical applied to metal surfaces to reveal hidden cracks; the dye seeps into fractures and is made visible with a developer spray.

E

Ear ProtectionSafety Precautions: Ear protection -- earplugs or earmuffs -- shields hearing from permanent damage when working around high-decibel tools like air chisels.
Edge JointWelding, Cutting and Removal: An edge joint is a joint between the edges of two or more parallel or nearly parallel members.
Elastic DeformationMetal Finishing and Body Filling: Elastic deformation is deformation that occurs when a material is not stretched beyond its elastic limit -- meaning it returns to its original shape.
ElasticityMetal Finishing and Body Filling: Elasticity is a material's ability to be stretched and then return to its original shape.
ElastomericPlastic Repair: Describing a polymer material that exhibits the high-elasticity, high-elongation, and elastic-recovery characteristics of natural rubber - the material class from which automotive flexible bumper fascias, flexible cladding, and trim components are made, and which requires special elasticizing additives in refinishing coatings to prevent cracking.
Electric Convertible TopGlass and Hardware: An electric convertible top is a convertible top raised and lowered by an electric motor and actuator assembly, as opposed to a top raised and lowered by hand.
Electric ToolMetal Finishing and Body Filling: An electric tool is a tool that operates on electrical power.
Electrical FiresSafety Precautions: Electrical fires occur when excessive current flow overheats wiring until the insulation melts and ignites, commonly caused by short circuits or collision-damaged wiring.
ElectrocutionSafety Precautions: Electrocution is a condition in which electricity passes through the human body, causing severe injury or death.
ElectrodeWelding, Cutting and Removal: An electrode is a metal rod used in arc welding that melts to help join the pieces being welded.
Electrode StickoutWelding, Cutting and Removal: Electrode stickout is the length of welding wire extending beyond the GMAW gun's contact tip before it reaches the arc, a key setting adjusted when tuning the welder for a given substrate.
Electronic Leak DetectorGlass and Hardware: An electronic leak detector is a two-part diagnostic tool using a high-frequency transmitter and receiver to locate water or air leaks through vehicle body seams, glass, and trim.
Electronic ShieldingWelding, Cutting and Removal: Electronic shielding is the practice of protecting a vehicle's on-board computers and sensor wiring from the strong magnetic fields and electrical interference generated by welding equipment.
Electronic StethoscopeGlass and Hardware: An electronic stethoscope is a diagnostic listening tool that amplifies and isolates mechanical noises such as rattles, squeaks, and vibrations to pinpoint their source in the vehicle body or hardware.
Electrostatic Discharge (ESD)Safety Precautions: A static electricity discharge that can invisibly damage sensitive electronic components, causing latent failures that show up later even though the part looks fine.
Energy AbsorbersOuter Body Panel Repairs and Replacements: Mechanical devices mounted between the bumper reinforcement and the vehicle frame rails that absorb low-speed impact energy, protecting the structure from damage during minor collisions.
Ethylene DichloridePlastic Repair: Ethylene dichloride is a chemical used as a solvent to cement plastic joints.
Ethylene Propylene Diene Monomer (EPDM)Plastic Repair: An ozone-resistant synthetic rubber that has replaced natural rubber in applications like weatherstripping, and appears in ISO material codes for certain plastic blends.
Event Data Recorder (EDR)Legal and Environmental Practices: A vehicle module, often called the vehicle's black box, that records data about a crash event; by law its data belongs to the vehicle owner and generally requires their consent to access.
EWP (AWS Pure Tungsten Electrode Classification)Welding, Cutting and Removal: The AWS classification code for an electrode made of essentially pure tungsten with no intentional alloying additions, used in GTAW/TIG welding.
ExplosionsSafety Precautions: An explosion is a fast-moving air pressure wave resulting from extremely rapid burning, such as igniting fumes near a fuel tank during welding.
ExtensionsVehicle Systems Knowledge: A socket extension is a straight bar that connects between a ratchet handle and a socket to provide the reach needed to access recessed or obstructed fasteners.
Exterior Door HandleGlass and Hardware: An exterior door handle is a device that permits opening a door from the outside.
Exterior Trim PieceGlass and Hardware: Exterior trim pieces are the moldings and other components applied to the outside of a vehicle.
Eye Flushing StationSafety Precautions: An eye flushing station is a safety fixture that delivers a steady flow of fresh water through nozzles to irrigate the eyes immediately after chemical or particle exposure, required to be within 10 seconds or 55 feet of any potential hazard.

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Fabricated PanelsOuter Body Panel Repairs and Replacements: Fabricated panels are hand-made repair parts created to fix small problems when no factory replacement panel is practical or available.
Face BarOuter Body Panel Repairs and Replacements: A face bar is a bare bumper with no hardware attachments.
FasciaOuter Body Panel Repairs and Replacements: The outer decorative plastic cover of a bumper assembly that conceals the reinforcement and energy absorbers; a cosmetic component with no structural load-bearing function.
Fastened PartsVehicle Systems Knowledge: Fastened parts are parts held onto a vehicle by bolts, nuts, screws, clips, and adhesives.
FastenersVehicle Systems Knowledge: Fasteners are the mechanical and adhesive devices - including bolts, nuts, screws, clips, and structural adhesives - that secure every component of a vehicle to the body, frame, and chassis.
Fatigue FailureVehicle Systems Knowledge: Fatigue failure is a metal failure resulting from repeated stress that alters the character of the metal so that it cracks.
Federal Motor Vehicle Safety Standard (FMVSS)Legal and Environmental Practices: The set of federal standards that test and regulate vehicle safety performance, including how OEM glass and structural components perform in a crash.
FEPA P-Grade Abrasive SystemMetal Finishing and Body Filling: The European/ISO sandpaper grit grading system, in which a higher P number means a finer grit -- distinct from the U.S. CAMI system.
FiberglassPlastic Repair: Fiberglass is a material composed of fine-spun filaments of glass, used as insulation and as reinforcement for a resin binder when repairing vehicle bodies.
Fiberglass ClothPlastic Repair: Fiberglass cloth is a woven fabric made of glass fibers used in layers with fiberglass resin to build up structural patches over holes or damaged areas in fiberglass and plastic panels.
Fiberglass MatPlastic Repair: Fiberglass mat is reinforcement material used with a resin to make repairs -- a series of irregularly distributed fiberglass strands forming a patch that the liquid resin saturates.
Fiberglass Reinforced Polyester (FRP)Plastic Repair: A composite material identified by visible glass fiber strands on its backside, produced by a hand lay-up process and repaired with fiber-reinforced patching techniques.
Fiberglass ResinPlastic Repair: Fiberglass resin is a two-part polyester-based liquid material that is catalyzed with a hardener and applied to fiberglass cloth or mat to bind the reinforcement layers into a rigid, structural composite patch.
Fiberglass-Reinforced Body FillerMetal Finishing and Body Filling: Fiberglass-reinforced body filler is a two-part polyester repair filler containing chopped fiberglass strands as its bulking agent, making it stronger and more waterproof than conventional filler, typically used as an initial base coat over welds or rust repairs before covering with lightweight filler.
Fibrous MatPlastic Repair: A fibrous mat is a reinforcing material consisting of nondirectional strands of chopped glass held together by a resinous binder.
FileMetal Finishing and Body Filling: A file is a tool with hardened ridges or teeth cut across its surface, used for removing and smoothing metal.
FillerMetal Finishing and Body Filling: Filler is any material used to fill or level a damaged area on a vehicle body.
Filler GratingMetal Finishing and Body Filling: Filler grating is the technique of using a coarse body file or cheese grater tool to rough-shape cured body filler by shaving down high spots and raised edges before block sanding.
Filler PanelOuter Body Panel Repairs and Replacements: A filler panel is a panel found between the bumper and the body.
Fillet WeldWelding, Cutting and Removal: A fillet weld is a triangular-profile weld joining two surfaces at an angle, one of the specific weld types (with plug and butt welds) a technician must be able to perform in flat, horizontal, vertical, and overhead positions.
Finishing HammerMetal Finishing and Body Filling: A finishing hammer is a lightweight body hammer with small, precisely crowned faces used after rough-out work to refine dented sheet metal to its final contour with controlled, accurate strikes.
Fire ExtinguisherSafety Precautions: A fire extinguisher is a metal tank filled with a chemical agent designed to quickly smother and stop a fire by depriving it of heat, fuel, or oxygen.
First-Aid KitSafety Precautions: A first-aid kit is a required shop safety supply containing sterile gauze, bandages, antiseptics, scissors, and other medical items needed to treat minor injuries such as cuts and burns on the job.
FlashbackWelding, Cutting and Removal: Flashback is a condition in which the oxygen-acetylene mixture burns back into the body of the welding torch.
Flat ChiselMetal Finishing and Body Filling: A flat chisel is a tool designed for shearing steel, including removing bolts and rivets.
Flat WeldingWelding, Cutting and Removal: Flat welding is the easiest and most productive welding position, where the workpieces lie horizontal and parallel to the floor so gravity assists in forming a consistent weld puddle with maximum penetration.
Flex AgentPlastic Repair: A flex agent (elastomer) is a chemical additive mixed into paint or primer before application to flexible plastic substrates such as bumper covers, preventing the cured film from cracking when the plastic flexes during normal use.
Floor JackSafety Precautions: A floor jack is portable equipment used to lift a vehicle, using a saddle to raise the front, sides, or rear.
Flux Cored WireWelding, Cutting and Removal: Flux cored wire is an electrode for flux cored arc welding, built as a tube with flux contained inside it.
Foam FillersOuter Body Panel Repairs and Replacements: Expanding foam material injected or placed into structural cavities to add rigidity and strength to structural parts and to reduce noise and vibration.
Framed DoorGlass and Hardware: A framed door is a door design in which the door frame surrounds and supports the glass.
Full Face ShieldSafety Precautions: A full face shield is a head-mounted safety device that covers the entire face from forehead to chin, protecting the eyes, face, and neck from flying debris, sparks, grinding particles, and chemical splashes.
Full Panel ReplacementOuter Body Panel Repairs and Replacements: The outer body panel procedure that removes the entire damaged panel at its original factory weld seams and replaces it with a new OEM, aftermarket, or salvage panel welded at the same attachment points - providing the highest structural and cosmetic restoration quality for a damaged panel at a cost typically higher than repair but lower than sectioning.
FusibilityWelding, Cutting and Removal: Fusibility is a measure of a material's ability to join another material while in a liquid state.
Fusion WeldWelding, Cutting and Removal: A fusion weld is a joining operation in which pieces of metal are heated to the melting point and joined together, often with a filler rod, then allowed to cool.
Fusion WeldingWelding, Cutting and Removal: Fusion welding is the category of welding processes in which metal pieces are heated to their melting point and joined together - with or without a filler material - to form a continuous, permanent bond as the molten metal cools.

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Galvanic CorrosionOuter Body Panel Repairs and Replacements: Accelerated corrosion that occurs when two dissimilar metals are placed in direct contact with each other in the presence of moisture, causing the less noble metal to corrode faster than it would on its own.
GapOuter Body Panel Repairs and Replacements: A gap is the distance between two points.
GarnishGlass and Hardware: Garnish is a decorative or finish molding around the inside of glass.
Garnish MoldingsGlass and Hardware: Garnish moldings are the interior moldings around a vehicle's glass, as distinct from the exterior reveal moldings around the same opening.
Gas Metal Arc Cutting (GMAC)Welding, Cutting and Removal: Gas metal arc cutting is an arc cutting process that severs metal by melting it with the heat of an arc struck between a continuous metal electrode and the work.
Gas Tungsten Arc Welding (GTAW)Welding, Cutting and Removal: An arc welding process using a non-consumable tungsten electrode and shielding gas, commonly known by its trade name TIG welding.
Gas-Metal Arc Welder (GMAW)Welding, Cutting and Removal: A welding process that feeds a continuous consumable wire electrode through a gun while shielding the weld pool with inert or mixed gas; universally known as MIG welding, it is the standard structural collision repair welding method.
GasketGlass and Hardware: A gasket is a rubber strip used to secure fixed glass on early-model vehicles, or a cork, rubber, or combined material used as a seal between two mating surfaces.
General-Purpose FileMetal Finishing and Body Filling: A general-purpose file is a flat, round, or half-round tool used to remove burrs and sharp edges from metal parts.
GhostingMetal Finishing and Body Filling: Ghosting is a body filler defect where an underlying shape, scratch, or repair outline becomes faintly visible through the finished, sanded filler surface.
Glass Installation KitGlass and Hardware: A pre-assembled package of all adhesive materials required for a compliant windshield or encapsulated glass replacement - typically including pinchweld primer, urethane adhesive, and butyl tape spacers - providing the complete sealing system needed to restore OEM glass adhesion, weather sealing, and structural contribution to roof crush resistance.
Glass RepairGlass and Hardware: The procedure of injecting resin into windshield chips or bull's-eyes and polishing out minor surface scratches to restore optical clarity and prevent crack propagation - a significantly less expensive alternative to full windshield replacement that is appropriate when the damage is outside the driver's primary viewing area and does not compromise glass structural integrity.
Glass Run ChannelGlass and Hardware: A glass run channel, also called a window channel, is the channel in which window glass is supported as it is raised and lowered.
Glass Setting TapeGlass and Hardware: An adhesive cloth or rubber tape cut to the length of a door glass lift channel or sash that cushions, seals, and secures the glass edge within its track.
Glass Trim PanelsGlass and Hardware: Glass trim panels fit over the edges of the windshield and back glass, and over the upper sections of the A-, B-, and C-pillars.
Globally Harmonized System (GHS)Safety Precautions: The international standard for classifying chemical hazards and their labeling symbols, used alongside or in place of systems like WHMIS.
Glue-Pulling Dent Repair (GPDR)Metal Finishing and Body Filling: Glue-Pulling Dent Repair (GPDR) is a paintless dent repair technique that bonds pulling tabs to the outer panel surface with adhesive, then uses those tabs to pull the dent out without drilling or welding.
GogglesSafety Precautions: Goggles are sealed safety eyewear that fits tightly against the face to protect the eyes from chemical splashes, solvent vapors, and welding torch glare, providing a level of coverage that safety glasses alone cannot achieve.
GougeMetal Finishing and Body Filling: A gouge is a sharp dent or crease in a panel produced by a focused impact that stretches the metal.
Grain PatternPlastic Repair: Grain pattern is the surface appearance and color variation of vinyl fabric.
Grater FileMetal Finishing and Body Filling: A grater file is a file used to shape body filler before it has completely hardened.
GrilleOuter Body Panel Repairs and Replacements: A grille is the decorative panel in front of the radiator.
GrinderMetal Finishing and Body Filling: A grinder is a high-speed abrasive power tool used in the collision shop to rapidly remove weld spatter, strip paint from metal, smooth welded joints, and prepare bare metal surfaces for repair work.
Groove WeldWelding, Cutting and Removal: A groove weld is a weld made in the groove between workpieces.

H

HacksawWelding, Cutting and Removal: A hacksaw is a hand saw used to cut metal.
Hammer-Off-DollyMetal Finishing and Body Filling: Hammer-off-dolly is a metal straightening technique in which the hammer strikes the panel slightly to one side of where the dolly is positioned, using the dolly's rebounding pressure to raise low spots while the hammer lowers adjacent high spots.
Hammer-On-DollyMetal Finishing and Body Filling: Hammer-on-dolly is a metal finishing technique in which the hammer strikes the panel directly over the dolly held against the back of the metal, creating a pinching action that smooths and levels small high spots and ridges.
Hard HatSafety Precautions: A hard hat is metal or plastic headgear worn to help protect the head from abrasions, hot sparks, and chemical sprays.
Hard-Faced HammerMetal Finishing and Body Filling: A hard-faced hammer is a hammer used to strike tools or to bend or straighten metal parts.
Hardener KneadingMetal Finishing and Body Filling: Hardener kneading is the preparatory step of working the body filler hardener tube by squeezing its contents back and forth before use, ensuring the hardener has a smooth, uniform consistency free of lumps or separation.
HardwareVehicle Systems Knowledge: Hardware means the hinges, hangers, and fasteners used in vehicle construction -- and, in a computing context, the physical equipment such as computers, printers, and drives.
HAZ (Heat-Affected Zone)Welding, Cutting and Removal: The heat-affected zone (HAZ) is the area around a weld that becomes hot during welding and should be kept as small as possible to prevent panel warping or component damage.
Hazard Communication StandardSafety Precautions: The OSHA regulation requiring a complete chemical inventory and hazard warnings for every hazardous substance used in the shop.
Hazardous Materials Identification System (HMIS)Safety Precautions: A U.S. chemical hazard labeling system that uses numeric fire, health, and reactivity ratings; its fire rating codes may appear on a label but aren't a universally required element the way OSHA/WHMIS hazard warnings are.
Hazardous WasteSafety Precautions: Hazardous waste is any solid or liquid material classified by the EPA as harmful to people or the environment due to characteristics of ignitability, corrosivity, reactivity, or toxicity, requiring special handling and disposal in the collision shop.
Head LinerGlass and Hardware: A head liner is the cloth or plastic material covering the roof area inside the passenger compartment, supported by metal rods.
Headliner AssemblyGlass and Hardware: The headliner assembly is the cloth or vinyl interior covering installed over the inside of the roof panel, often incorporating grab handles, dome light trim, sun visor mounting, and a sound-deadening backing.
Health and Safety at Work Act (HASAWA)Safety Precautions: The United Kingdom's foundational workplace health and safety law, which applies to every employee and employer regardless of seniority.
Heat Effect ZoneWelding, Cutting and Removal: The heat effect zone is the area of base metal surrounding a weld that is exposed to enough heat to alter its mechanical properties, and which must be minimized during welding to prevent panel warpage, weakening of high-strength steel, and damage to nearby components.
Heat GunPlastic Repair: A heat gun is an electric hand-held tool that blows heated air to soften plastic parts or for speed drying, used where controlled heat is needed such as repairing vinyl roofs and other plastics.
Heat ShrinkMetal Finishing and Body Filling: Heat shrinking is heating metal with a torch, working it flat with a hammer and dolly, then quenching it with water to shrink stretched metal back to its correct area.
Heat Sink CompoundWelding, Cutting and Removal: Heat sink compound is a clay-like thermal management material applied to body panels around a weld area to absorb and dissipate heat, preventing the welding temperature from spreading and creating a large heat-affected zone.
Heat-Absorbing CompoundWelding, Cutting and Removal: Heat-absorbing compound is a clay-like material that reduces the size of the heat-affected zone and helps protect nearby surfaces during welding or heat application.
Heavy-Bodied SealersOuter Body Panel Repairs and Replacements: Heavy-bodied sealers are thick, cartridge-applied seam sealing compounds used to fill body panel seams from 1/8 to 1/4 inch wide, providing waterproof, flexible protection against corrosion at panel joints.
Hem SeamOuter Body Panel Repairs and Replacements: A hem seam is a door bottom seam formed by bending the outer panel hem flange over the inner panel flange.
Hemming ToolOuter Body Panel Repairs and Replacements: A hemming tool is a pneumatic tool used to create a hem seam.
High-Efficiency Particulate Air (HEPA)Safety Precautions: A high-efficiency air filter used in vacuums to safely capture extremely fine hazardous dust, such as asbestos or fiberglass particles, without releasing it back into shop air.
High-Intensity Discharge (HID)Glass and Hardware: A headlamp technology that requires a ballast to step up battery voltage to strike and sustain an arc discharge, rather than running directly on 12 volts.
Hood HingesOuter Body Panel Repairs and Replacements: Hood hinges are the pivot assemblies bolted between the hood and the body structure that allow the hood to open and close while maintaining proper panel alignment, and which are commonly damaged or bent in frontal collisions requiring inspection and possible replacement.
Hood LatchGlass and Hardware: The hood latch is the mechanism that keeps the hood closed and releases it when activated.
Hood PanelOuter Body Panel Repairs and Replacements: The hood panel is the large panel filling the space between the two front fenders that closes off the engine compartment -- a sheet of shaped steel, aluminum, or plastic forming part of the car body.
Hood Prop ToolOuter Body Panel Repairs and Replacements: A rubber-tipped extension rod used to hold a hood open and supported while a technician removes the hood shocks (struts) and other hardware.
Hood StopOuter Body Panel Repairs and Replacements: A hood stop controls the height of the front of the hood.
Hood StrikerOuter Body Panel Repairs and Replacements: The hood striker is a metal pin or loop mounted to the underside of the hood that engages and locks into the spring-loaded hood latch mechanism on the body, securing the hood in the closed position.
Hood StrutOuter Body Panel Repairs and Replacements: Hood struts are gas-charged cylindrical lift supports (hood shocks) that automatically hold the hood in the open position when raised, eliminating the need for a manual prop rod during engine compartment access.
HoodingPlastic Repair: Hooding is applying a cover or hood over the headlight area, constructed of epoxy resin and fiberglass.
Horizontal WeldingWelding, Cutting and Removal: Horizontal welding is a position in which the workpieces are oriented vertically but the weld joint runs horizontally, requiring the technician to angle the gun upward to counteract the downward pull of gravity on the molten weld puddle.
Hot Gas WeldingPlastic Repair: Hot gas welding is the use of air or inert gas heated by a torch to melt and fuse thermoplastics and plastic filler rod.
Hot Glue GunPlastic Repair: A hot glue gun is an electrically heated device used to melt and apply adhesive to plastics and other materials.
Hot-MeltPlastic Repair: Hot-melt is a polymer adhesive applied in its molten state.
HSSVehicle Systems Knowledge: HSS is an abbreviation for high-strength steel.
Hydraulic LiftSafety Precautions: A hydraulic lift is a shop equipment system that uses pressurized fluid to raise a vehicle off the ground for undercarriage access, requiring proper vehicle positioning at designated lift points to prevent tipping or structural damage.
HydrocarbonLegal and Environmental Practices: A hydrocarbon is a compound that contains carbon and hydrogen.

I

Impact ToolVehicle Systems Knowledge: An impact tool is an electric or pneumatic hand tool used to tighten or loosen bolts and nuts.
Impact WrenchVehicle Systems Knowledge: An impact wrench is an electrically or pneumatically driven hand tool used for rapidly turning nuts and bolts to tighten or loosen them.
Impervious GlovesSafety Precautions: Impervious gloves are latex or synthetic rubber gloves worn to prevent skin exposure when working with harmful chemicals.
ImpuritiesWelding, Cutting and Removal: Impurities are foreign materials such as paint, rust, or other contaminants that can substantially weaken a weld joint.
Induction HeatingMetal Finishing and Body Filling: Induction heating is the generation of heat within a substrate by the application of an electromagnetic field.
Inert GasWelding, Cutting and Removal: An inert gas is a non-reactive, non-combining gas such as argon or helium, used to shield a weld from the surrounding air.
InsertWelding, Cutting and Removal: A weld insert (backing strip) is a piece of the same base metal placed behind a butt weld joint to improve fit-up, support the weld puddle, prevent burn-through, and restore the full structural strength and rigidity of the original panel.
InstallOuter Body Panel Repairs and Replacements: To install is to attach or insert a part, component, or assembly onto a vehicle.
Insurance Institute for Highway Safety (IIHS)Legal and Environmental Practices: An independent vehicle safety rating organization whose testing standards (such as for roof strength) are separate from and different than NHTSA's.
Interior Door Trim AssemblyGlass and Hardware: The interior door trim assembly is the coverings and hardware on the cabin surface of a door -- the upholstery and moldings on the inside of the vehicle.
Interior LockGlass and Hardware: An interior lock is a mechanical lever, knob, or button attached by a rod to the lock portion of the latch assembly.
Interior TrimOuter Body Panel Repairs and Replacements: Interior trim refers to all upholstery and moldings on the inside of the vehicle.
Interior Trim PanelsGlass and Hardware: Interior trim panels are the decorative and functional plastic, cloth, and vinyl covers installed in the passenger compartment over structural pillars, door interiors, and floor and roof areas, attached primarily with snap-in plastic clips and screws.
International Autobody Congress And Exposition (NACE)Legal and Environmental Practices: NACE is the International Autobody Congress and Exposition, the collision repair industry's trade event, named in the source material alongside I-CAR and the industry trade associations.
International System Of Units (SI)Vehicle Systems Knowledge: SI stands for the International System of Units, and the letters SI are the marking that identifies metric threads, which come in both coarse and fine.
IronVehicle Systems Knowledge: Iron is a basic element.

J

JackSafety Precautions: A jack is a device used for heavy lifting, such as lifting a vehicle.
Joint Fit-UpWelding, Cutting and Removal: Joint fit-up is holding work pieces in alignment before welding.

K

KerfWelding, Cutting and Removal: A kerf is the space left after metal has been removed by cutting with a saw or torch.
Keyless EntryGlass and Hardware: Keyless entry systems use a keypad panel on the outside of the driver's door; a preset series of numbers is punched in and the door unlocks.
Kick OverMetal Finishing and Body Filling: Kick over is a term used to indicate that a plastic filler has hardened.
Kick PadGlass and Hardware: A kick pad is the panel that fits between the cowl and the front door opening.
KinkMetal Finishing and Body Filling: A sharp, angular metal deformation with a fold angle exceeding 90 degrees - distinct from a gradual bend - in which the metal has been folded so sharply that the inner radius has been severely compressed and work-hardened, making full recovery to the original shape impossible and typically requiring panel replacement rather than repair.

L

LaminationPlastic Repair: Lamination is a process in which layers of materials are bonded together.
Lap WeldWelding, Cutting and Removal: A lap weld is a weld made along the top edge of an overlapping piece.
LatchGlass and Hardware: A latch is a mechanism that grasps and holds doors, hoods, and trunk lids closed.
Liability InsuranceLegal and Environmental Practices: Liability insurance is insurance that covers the policyholder for damages to the personal property of others.
LiftSafety Precautions: A lift is a hydraulic mechanism used to raise a vehicle off the floor.
Light Body FillerMetal Finishing and Body Filling: Light body filler is a low-density, fine-grained polyester body filler formulated for easy sanding and quick final leveling of repaired metal panels, applied in thin skim coats over the primary filler layer to achieve a smooth, block-sand-ready surface.
Liquid VinylPlastic Repair: Liquid vinyl is a paint consisting of vinyl in an organic solvent.
Liquid Vinyl Patching CompoundPlastic Repair: Liquid vinyl patching compound is a thick material used to repair severely damaged areas of vinyl, including holes and tears in vinyl upholstery and similar applications.
LockGlass and Hardware: A lock is a mechanism that prevents a latch assembly from operating.
Lock CylinderGlass and Hardware: The lock cylinder is the mechanism operated with a key in a mechanical lock system.
Lock-Out ToolGlass and Hardware: A lock-out tool is a device used to open a door when the latch is inoperative or the keys are lost or locked inside.
Lockout/Tagout (LOTO)Safety Precautions: A safety procedure that physically disables and labels energized equipment (from a high-voltage vehicle system to shop machinery or an electrical breaker) to prevent it from being energized while a technician is servicing it.
Long-Hair Fiberglass FillerMetal Finishing and Body Filling: Long-hair fiberglass filler is a reinforced polyester body filler containing long fiberglass strand reinforcements that provide superior strength and waterproof properties for repairing rusted-through panels, large holes, and plastic substrates, though its difficulty to sand limits it to rough-filling applications.
Low CrownMetal Finishing and Body Filling: A low crown is a damage area with a slightly convex curve -- a panel area with very little outward curvature.
Lower Glass SupportGlass and Hardware: A lower glass support is a support placed at the bottom edge of the window opening.

M

Manual Metal Arc Welding (MMA)Welding, Cutting and Removal: A welding process, commonly known as stick welding, where the electrode itself is consumed as filler metal, melted by the heat of an electric arc.
Manually Operated SeatGlass and Hardware: A manually operated seat is a seat system that is adjusted back and forth on a track by hand.
Manufacturer's InstructionsSafety Precautions: Manufacturer's instructions are the official product use, safety, and application procedures provided by a product manufacturer - printed on labels for paint and chemicals, and in manuals for equipment - that must be followed to ensure correct results and safe use.
Mechanical FastenerVehicle Systems Knowledge: A mechanical fastener is a device -- such as screws, nuts, bolts, rivets, and spring clips -- used for the adjustment and replacement of assemblies or components.
MechanismVehicle Systems Knowledge: A mechanism is the working parts of an assembly.
Melt-Flow Plastic WeldingPlastic Repair: Melt-flow plastic welding is an airless plastic repair method in which a heated shoe tip is pressed into a V-grooved plastic joint while a compatible welding rod is simultaneously melted and flowed into the groove, fusing the rod material to the base plastic.
Metal Inert Gas (MIG) WeldingWelding, Cutting and Removal: The arc welding process most widely used in automotive collision repair, in which a continuously fed wire electrode carries electrical current that creates an arc at the weld, melting and depositing the wire as filler metal, while a co-flowing shielding gas blankets the weld pool to prevent atmospheric oxygen and nitrogen contamination.
Metal SnipsWelding, Cutting and Removal: Metal snips are a hand-held scissor-like tool used to cut thin metal.
MetallurgyVehicle Systems Knowledge: Metallurgy is the study of metals and the technology of metals.
Metalworking AreasMetal Finishing and Body Filling: Metalworking areas are the designated shop zones where structural and body panel repair operations - including metal straightening, grinding, welding, and body filling - are performed, separate from surface preparation and painting areas to prevent metal dust and grinding particles from contaminating paint work.
Methyl Ethyl Ketone Peroxide (MEKP)Safety Precautions: An organic peroxide catalyst used to cure fiberglass resin; it is extremely irritating to skin and can cause chemical burns if not washed off immediately.
MIG BrazingWelding, Cutting and Removal: MIG brazing is a joining process using standard MIG welding equipment with a plug weld setup, required by some manufacturers for high-strength steel repairs where a full fusion weld would compromise the steel's strength.
MIG BronzeWelding, Cutting and Removal: MIG bronze is a brazing process that uses a MIG welder with bronze filler wire to join panels with less heat distortion than a standard steel MIG weld.
MIG Spot WeldingWelding, Cutting and Removal: MIG spot welding is the process of making spot welds with the heat of an arc, often used to tack panels in place before welding with continuous MIG welds or compression resistance spot welding, and used primarily where resistance spot welding equipment cannot reach.
Mill and Drill PadsOuter Body Panel Repairs and Replacements: Mill and drill pads are factory-applied bonded reinforcement pads on space-frame plastic panels that serve as attachment and alignment reference points during both manufacturing and collision repair replacement of structural plastic body panels.
Mirror Bracket AdhesiveGlass and Hardware: Mirror bracket adhesive is a strong bonding material used to mount a rear-view mirror bracket to the inside of a windshield.
MisalignedOuter Body Panel Repairs and Replacements: Misaligned describes uneven spacing, as between body panels.
Mixing BoardMetal Finishing and Body Filling: A mixing board is a flat surface used for mixing body filler and hardener.
Mold Core MethodPlastic Repair: The mold core method is a procedure used to repair curved or irregularly shaped sections.
Molded CorePlastic Repair: A curved body repair part made by applying plastic repair material over a form or pattern and then removing the cured material to use as a matching contour piece.
Molding ClipGlass and Hardware: A molding clip is a mechanical fastener used to secure trim.
Molding ToolOuter Body Panel Repairs and Replacements: A molding tool (power knife) is a thin-bladed hand tool used to cut through the adhesive bond of adhesive-held body moldings, allowing them to be removed without damage to the molding or the underlying painted panel surface.
Movable GlassGlass and Hardware: Movable glass is a window designed to be moved up and down or side to side for opening and closing.
Movable SectionVehicle Systems Knowledge: A movable section is a component held in position by a mechanical fastener.
MudMetal Finishing and Body Filling: Mud is a slang term for ready-to-use plastic filler.

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National Automotive Technicians Education Foundation (NATEF)Legal and Environmental Practices: NATEF is the nonprofit foundation created to evaluate automotive training programs and formally recognize the ones that meet its standards.
National Emission Standards for Hazardous Air Pollutants (NESHAP)Legal and Environmental Practices: The federal National Rule that sets the minimum VOC and application-technique requirements every automotive refinishing facility in the U.S. must meet.
National Fire Protection Association (NFPA)Safety Precautions: The organization behind the NFPA 704 hazard diamond, which uses color-coded quadrants to rate a material's health, flammability, and reactivity hazards on a 0-4 scale.
National Highway Traffic Safety Administration (NHTSA)Legal and Environmental Practices: The federal agency that sets and regulates motor vehicle safety standards.
National Institute For Automotive Service Excellence (NIASE)Legal and Environmental Practices: NIASE is the original name of the certifying body that later shortened its name to ASE -- the organization that writes and administers the automotive technician certification tests.
National Institute for Occupational Safety and Health (NIOSH)Safety Precautions: The National Institute for Occupational Safety and Health (NIOSH) is the U.S. federal research agency within the CDC that conducts research and makes recommendations to prevent work-related illnesses and injuries - most relevant to collision repair through its approval and testing of respiratory protection equipment.
Needle Nose PliersOuter Body Panel Repairs and Replacements: Needle nose pliers are hand tools with long, tapered jaws used to grasp small parts, reach into tight spaces, and perform electrical tasks, often incorporating wire cutting edges and wire strippers in the same tool.
NegligentLegal and Environmental Practices: Negligent means careless or irresponsible.
Neutral FlameWelding, Cutting and Removal: A neutral flame is an oxyacetylene torch flame adjusted to eliminate the inner cone acetylene feather, achieved by mixing acetylene and oxygen in a 1:1 ratio by volume.
NibblerWelding, Cutting and Removal: A nibbler is a power hand tool used to cut small bites out of sheet metal.
Nitrile GloveSafety Precautions: Nitrile gloves are gloves used for protection when working with paints, solvents, catalysts, and fillers.
Nondestructive TestWelding, Cutting and Removal: A nondestructive test is a spot weld quality verification method in which a chisel is driven between the welded panels to create a small gap, confirming weld strength without fully separating the joint, allowing the repair to continue if the weld passes.
Nonferrous MetalVehicle Systems Knowledge: A nonferrous metal is a metal that contains no iron -- such as aluminum, brass, bronze, copper, lead, nickel, and titanium.
Nonparallel Body GapsOuter Body Panel Repairs and Replacements: Nonparallel body gaps are uneven or tapered openings between adjacent panels (doors, hood, trunk lid, fenders) that indicate misalignment caused by structural damage, shifted mounting hardware, or worn hinges and latches.

O

Occupational Safety and Health Administration (OSHA)Safety Precautions: The Occupational Safety and Health Administration (OSHA) is the U.S. federal agency within the Department of Labor that sets and enforces mandatory workplace safety and health standards, conducts inspections, and imposes penalties for non-compliance - governing the working conditions of every collision repair shop in the United States.
OEM Repair ProceduresOuter Body Panel Repairs and Replacements: OEM repair procedures are the vehicle manufacturer's official step-by-step instructions for repairing or replacing structural and body components on a specific make and model vehicle.
OEM Replacement PanelsOuter Body Panel Repairs and Replacements: OEM replacement panels are body and structural panels manufactured by the same company that built the vehicle, purchased through the manufacturer's dealer network, and guaranteed to match original factory fit, finish, and structural specifications.
Off-The-Dolly DingingMetal Finishing and Body Filling: Off-the-dolly dinging is a technique of holding the dolly away from the raised areas being struck by the hammer.
One-Part Spot PuttiesMetal Finishing and Body Filling: One-part spot putties are single-component pre-mixed fillers applied directly from the tube to fill very small surface imperfections (pinholes, small sand scratches) over primer, curing slowly through solvent evaporation rather than chemical reaction.
One-Time Use FastenersOuter Body Panel Repairs and Replacements: One-time use fasteners are specific bolts or fasteners, such as certain stretch bolts, that a manufacturer designates as single-use because their clamping properties are compromised once removed.
Open-End WrenchOuter Body Panel Repairs and Replacements: An open-end wrench is a hand tool with two open, C-shaped jaws used to loosen and tighten fasteners in locations where insufficient clearance prevents the use of a box-end wrench, gripping only two faces of the fastener head.
Outer Body PanelsOuter Body Panel Repairs and Replacements: The exterior panels forming the vehicle's visible surface, classified as bolt-on (fenders, hoods, deck lids) or weld-on/bonded (quarter panels, door skins) - each requiring a distinct repair or replacement procedure.
Outer-Belt Weather StripGlass and Hardware: The outer-belt weather strip is the material located between the door panel and the window glass that prevents dirt, air, and moisture from entering.
Over CatalyzingMetal Finishing and Body Filling: Over catalyzing is a body filler defect caused by mixing too much hardener into the filler, leading to rapid curing, cracking, or shrinkage problems.
Overhead WeldingWelding, Cutting and Removal: Overhead welding is welding performed with the workpiece upside down or over the welder's head, considered the most difficult welding position.
OverlayPlastic Repair: Overlay is a term used for a surfacing mat.
Oxidizing FlameWelding, Cutting and Removal: An oxidizing flame is a welding flame obtained by mixing slightly more oxygen than acetylene, used for welding brass and bronze.

P

Paint Flexibility AdditivePlastic Repair: Paint flexibility additive (flex agent) is an additive mixed into primer or paint to keep the finish flexible after curing, preventing it from cracking on flexible plastic parts.
Paintless Dent Repair (PDR)Outer Body Panel Repairs and Replacements: A metalworking technique that removes minor dents, dings, and hail damage from body panels by pushing or massaging the metal back to its original shape from behind the panel using specialized rods and tabs - without disturbing the existing paint finish, eliminating the need for filler, priming, or repainting.
Panel AdjustmentOuter Body Panel Repairs and Replacements: Panel adjustment is the process of shifting or repositioning an installed body panel - such as a hood, door, or fender - to bring its gaps and alignment into proper spec with the surrounding panels.
Panel Bonding AdhesivePlastic Repair: Panel bonding adhesive is a structural adhesive used for bonding panels to space frames.
Panel Clamping PliersOuter Body Panel Repairs and Replacements: Panel clamping pliers, commonly known as vise grips, are locking pliers used to temporarily hold a replacement body panel in its correct position while welding or panel bonding adhesive is applied.
Partial Replacement PanelsOuter Body Panel Repairs and Replacements: Partial replacement panels are factory-made or aftermarket panel sections engineered to replace only a damaged or rusted portion of a larger body panel, making them a cost-efficient alternative to full panel replacement.
PathogensSafety Precautions: Pathogens are microorganisms that can cause illness and disease.
Peel-off FrontOuter Body Panel Repairs and Replacements: A type of salvage front-end assembly consisting of only the outer body panels (fenders, hood, grille surround, and outer fascia) stripped of all inner structure, radiator support, cooling system components, and hardware - used when the customer vehicle's inner structure is undamaged but the outer skin panels require replacement.
Permissible Exposure Limit (PEL)Safety Precautions: The maximum concentration of a substance a worker can be exposed to over a set time period (typically an 8-hour shift) without expected harm.
Personal Protective EquipmentSafety Precautions: Personal Protective Equipment (PPE) is the category of wearable safety gear - including eye protection, respiratory protection, hearing protection, gloves, and protective clothing - worn by collision repair technicians to protect against the specific chemical, mechanical, thermal, and noise hazards present in the shop.
Phillips ScrewdriverOuter Body Panel Repairs and Replacements: A Phillips screwdriver is a hand tool with a four-prong, X-shaped tip designed to drive Phillips-head (cross-head) screws, available in sizes #1 through #4 to match different screw sizes - the most common screwdriver type in automotive interior trim and accessory fasteners.
PickGlass and Hardware: A pick is a pointed hand tool used to reposition small retaining clips, fasteners, and trim components into their correct alignment without marring or damaging surrounding material.
Picking HammerMetal Finishing and Body Filling: A picking hammer is a body hammer with a pointed tip on one end and a flat face on the other, primarily used to raise small low spots in sheet metal from the back side of the panel.
Pillar Trim PanelsGlass and Hardware: Pillar trim panels are the interior plastic covers that fit over the structural A-, B-, and C-pillars, concealing the pillar metal and any wiring or safety components routed inside.
Pipe WrenchOuter Body Panel Repairs and Replacements: A pipe wrench is an adjustable wrench with angled, toothed jaws specifically designed to grip and rotate round or cylindrical objects such as pipes, pipe fittings, and round studs that flat-jaw wrenches cannot hold.
PlasmaWelding, Cutting and Removal: Plasma is a gas heated to a partially ionized condition, enabling it to conduct an electric current.
Plasma Arc CutterWelding, Cutting and Removal: A metal-cutting tool that generates a high-velocity, electrically conductive stream of superheated plasma gas that simultaneously melts and forcibly ejects metal from the cut line - producing a narrow, precise kerf through steel, aluminum, or any electrically conductive metal faster and with less heat distortion to adjacent metal than torch cutting.
Plasma Arc CuttingWelding, Cutting and Removal: Plasma arc cutting is a thermal cutting process that generates an intensely focused, superheated gas stream to melt and remove metal with clean, precise cuts and minimal heat distortion, making it well-suited for cutting thin automotive sheet metal.
PlasticPlastic Repair: Plastic is a broad category of synthetic polymer materials used extensively in automotive construction, divided into two main types: thermoplastics, which can be reheated and reshaped, and thermosetting plastics, which cure permanently and cannot be re-melted.
Plastic Flexibility TestPlastic Repair: A plastic flexibility test is used to help identify what type of plastic is used in a part.
Plastic MemoryPlastic Repair: Plastic memory is the inherent tendency of a thermoplastic part to return to its original molded shape when heat is applied after the part has been bent or deformed.
Plastic Speed WeldingPlastic Repair: Plastic speed welding uses a specially designed tip to produce a more uniform weld at a higher rate of speed.
Plastic Stitch-Tamp WeldingPlastic Repair: Plastic stitch-tamp welding is a hot-air plastic welding technique used on hard, rigid plastics, in which the welder alternately stitches (moves) and tamps (presses) the melted rod into the base plastic to ensure the two fully fuse together.
Plastic WeldingPlastic Repair: Plastic welding is the process of using heat to fuse a plastic filler rod into a damaged thermoplastic part, creating a permanent molecular bond to repair tears, cracks, and gouges.
PliersOuter Body Panel Repairs and Replacements: Pliers are versatile hand tools with hinged jaws used to grip, hold, bend, and cut wires, clips, pins, and other small components throughout the collision repair process.
Plug WeldWelding, Cutting and Removal: A plug weld is made by adding metal into a hole and fusing all the metal together.
Plug Weld HolesWelding, Cutting and Removal: Plug weld holes are circular openings drilled or punched through the top panel in a multi-panel joint, allowing the MIG welder to fuse the top panel to the backing panel by filling the hole with weld metal to replicate factory spot welds.
Pneumatic Flange ToolOuter Body Panel Repairs and Replacements: A pneumatic flange tool is an air-operated hand tool used to form an offset crimp along the joint edge of a panel.
PolyblendPlastic Repair: A polyblend is a plastic that has been modified by the addition of an elastomer.
PolyesterMetal Finishing and Body Filling: A two-part thermosetting synthetic resin used as the binder in automotive body filler and glazing putty - mixed with a peroxide hardener (cream hardener) that triggers a chemical cross-linking reaction causing the polyester to solidify from a pliable paste into a rigid, sandable compound.
Polyester Glazing PuttyMetal Finishing and Body Filling: Polyester glazing putty is a high-solids filler material applied over primer coats to fill small surface imperfections such as pinholes, sand scratches, and minor low spots before the topcoat is applied.
PolyethylenePlastic Repair: Polyethylene is a thermoplastic material used for interior and some underhood applications.
PolypropylenePlastic Repair: Polypropylene is a thermoplastic material used for interior and some underhood applications.
Polyvinyl Butyral (PVB)Glass and Hardware: The plastic interlayer bonded between two sheets of glass in laminated safety glass, which holds broken fragments together.
Polyvinyl ChloridePlastic Repair: Polyvinyl chloride is a thermoplastic material used in pipes, fabrics, and other upholstery materials.
PoolWelding, Cutting and Removal: A pool is the area of molten metal created by the heat of the welding process.
Pop Rivet GunVehicle Systems Knowledge: A pop rivet gun is a hand-held tool designed to place and secure rivets into a blind hole.
PorosityWelding, Cutting and Removal: Porosity is voids or gas pockets in a material.
Power ToolMetal Finishing and Body Filling: A power tool is a tool that operates on electrical, hydraulic, or pneumatic power -- using air pressure, oil pressure, or electrical energy to help make repairs.
PPMLegal and Environmental Practices: PPM is an abbreviation for parts per million.
Press FitVehicle Systems Knowledge: A press fit is a joining technique in which one part is forced into another.
Pressure WeldingWelding, Cutting and Removal: Pressure welding is a category of welding in which metal is heated to a softened or plastic state by electrodes and then fused by applying mechanical pressure, with electric resistance spot welding being the most common form used in automotive manufacturing.
Pull RodMetal Finishing and Body Filling: A pull rod is a tool that allows repairs to be performed from the outside of a damaged panel.
Pull TabMetal Finishing and Body Filling: A pull tab is a metal tab welded to a damaged panel that allows the use of a slide hammer.
Push-Pull TorchWelding, Cutting and Removal: A push-pull torch is an aluminum MIG welding torch with a secondary wire feeder that pulls wire toward the torch while the main feeder pushes it, preventing the soft aluminum wire from tangling or jamming.
PuttyMetal Finishing and Body Filling: Putty is a material used to fill flaws.
PVCPlastic Repair: PVC is an abbreviation with two meanings: polyvinyl chloride, a type of plastic, and pigment volume content, the percentage of pigment material in a paint.

Q

Quarter PanelOuter Body Panel Repairs and Replacements: A quarter panel is the side panel extending from the rear door to the end of the vehicle.

R

RatchetMetal Finishing and Body Filling: A hand tool with a reversible ratcheting mechanism that turns a socket onto or off a fastener in one direction while allowing the handle to swing back and forth without lifting the socket off the fastener.
Ratchet HandleOuter Body Panel Repairs and Replacements: A ratchet handle is a socket wrench drive tool with an internal ratcheting mechanism that allows the socket to turn the fastener in one direction while slipping freely in the reverse direction, so the socket never needs to be removed from the fastener during use.
Reaction Injection MoldingPlastic Repair: Reaction injection molding is a process that injects reactive polyurethane, polyurea, or dicyclopentadiene resin into a mold, where the resin reacts and cures into the finished part.
Rear Compartment LidOuter Body Panel Repairs and Replacements: The rear compartment lid is the trunk lid -- the panel and reinforcement that covers the luggage compartment.
RegulatorGlass and Hardware: A regulator is the door-mounted gear and arm mechanism used to raise and lower window glass -- the term also names a device used to control pressure.
Regulatory ObligationsLegal and Environmental Practices: Regulatory obligations are the federal, state, and local legal requirements a collision repair facility must recognize and follow in the course of doing repair work.
Reinforced PlasticPlastic Repair: Reinforced plastic is a category of structural composite materials used for automotive body panels, including sheet-molded compound (SMC), fiber-reinforced plastic (FRP), and reinforced reaction injection-molded polyurethane (RRIM), which combine plastic resin with reinforcing fibers for added strength.
Replacement PanelsOuter Body Panel Repairs and Replacements: Replacement panels are full, unsectioned body panels supplied by the OEM, aftermarket manufacturers, or salvage yards, installed by welding or bonding in place of a severely damaged original panel to restore the vehicle to pre-accident structure and appearance.
ResinPlastic Repair: Resin is a term used for polyester or epoxy resin.
Resistance Spot Welding (RSW)Welding, Cutting and Removal: A welding process that joins metal by applying electrodes to each side of the workpieces and passing current through them, without a filler wire or shielding gas.
Resource Conservation and Recovery Act (RCRA)Safety Precautions: The federal law that regulates hazardous waste generation and disposal, including reduced requirements for shops that qualify as small-quantity generators.
Respirator Fit TestSafety Precautions: A respirator fit test is a pre-use procedure that verifies an air-purifying or half-mask respirator seals correctly against the wearer's face, preventing contaminated air from bypassing the filter cartridges.
Retaining ClipVehicle Systems Knowledge: A retaining clip is a spring-type device used to secure one component to another.
Reveal FileMetal Finishing and Body Filling: A reveal file is a curved file used to shape tight curves or rounded panels.
Reveal MoldingsGlass and Hardware: Reveal moldings are the exterior moldings around a vehicle's glass, sometimes secured by clips attached to the body with welded-on studs, bolts, or screws.
Rivet BondingWelding, Cutting and Removal: Rivet bonding is a structural joining method that combines mechanical rivets with structural adhesive for a joint stronger and more corrosion-resistant than either method alone.
Roloc Grinding DiscsSurface Preparation: Roloc grinding discs are small, round abrasive discs with a quick-change twist-lock mandrel that mount on a right-angle die grinder, used to rapidly strip paint, rust, and old body filler from weld joints, spot-weld locations, repair areas, and hard-to-reach spots before panel repair or welding.
Rough-outOuter Body Panel Repairs and Replacements: A preliminary pulling and straightening operation performed on a replacement panel before final installation - using controlled body shop pulls to adjust the panel's shape so that it aligns correctly with adjacent structure and panels, correcting any dimensional differences or distortion in the replacement panel that would otherwise require shimming or forced fit.
Rubber StopOuter Body Panel Repairs and Replacements: A rubber stop is an adjustable hood bumper used to make minor alignment adjustments.
RustoutOuter Body Panel Repairs and Replacements: Rustout is through-metal corrosion in which rust has completely penetrated the steel panel, creating actual holes or perforations rather than surface oxidation, most commonly occurring on lower body panels exposed to road moisture, salt, and debris.

S

Saddle JointWelding, Cutting and Removal: A saddle joint is a joint between round tubes in which one tube is cut to fit around the contour of the other.
Safety Data Sheets (SDS)Safety Precautions: Safety Data Sheets (SDS) are standardized technical documents provided by chemical product manufacturers that describe hazardous ingredients, health risks, PPE requirements, safe handling procedures, and emergency response information for potentially dangerous materials.
Safety GlassesSafety Precautions: Safety glasses are protective eyewear.
Safety ProgramSafety Precautions: A safety program is a shop's written policy setting rules for equipment use and chemical disposal, designed to protect the health and welfare of all employees.
Sander PadMetal Finishing and Body Filling: A sander pad is the soft rubber or foam backing disc or block that mounts to a power sander and provides a compliant surface to hold sandpaper and distribute sanding pressure evenly across the work surface.
ScrewdriverVehicle Systems Knowledge: A screwdriver is a hand-held tool, sometimes pneumatically or electrically powered, used to tighten or loosen screw-type fasteners.
Sealing StripGlass and Hardware: A sealing strip is a strip inside the door that prevents dust from entering while still allowing water to drain through the drain holes.
Seam SealersPreparation: Factory-matched materials applied to body panel seams, hem flanges, and structural joints to block water, prevent corrosion, and reduce noise - every seam disturbed during repair must be resealed with the OEM-specified material type.
Seat AssemblyGlass and Hardware: A seat assembly is the complete seating unit in a vehicle, comprising the seat cushion, seat back, headrest, seat tracks, and any integrated electrical accessories such as power adjustment motors, heating elements, and position sensors.
Seat BackGlass and Hardware: The seat back is the upright rear section of a vehicle seat that supports the occupant's back, consisting of a metal frame, foam padding, and a cloth, vinyl, or leather cover.
Seat CushionGlass and Hardware: The seat cushion is the horizontal lower section of a vehicle seat that the occupant sits on, consisting of a metal or plastic frame, foam padding, and an upholstery cover.
Seat TrackGlass and Hardware: A seat track is the sliding rail assembly that mounts the seat assembly to the vehicle floor pan and allows the seat to be adjusted forward and backward to accommodate occupants of different sizes.
SectioningWelding, Cutting and Removal: A structural repair technique in which only the damaged portion of a panel or structural member is cut out and replaced - either at a location-specific section joint (partial panel replacement) or at a factory body seam (full section replacement, also called clipping) - requiring precise cutting, fitting, and welding to restore structural integrity and geometry.
Self-Piercing Rivet (SPR)Vehicle Systems Knowledge: A rivet that pierces and joins metal panels without a pre-drilled hole, leaving a backside hole that must be filled with structural adhesive to prevent corrosion.
Sheet Molding CompoundPlastic Repair: Sheet molding compound is a thermoset, fiber-reinforced composite plastic that can be formed into strong and stiff body components.
Sheet-Molded Compound (SMC)Plastic Repair: Sheet-molded compound (SMC) is a fiberglass-reinforced thermoset polyester composite material used to manufacture body panels such as hoods, fenders, and doors, valued for its light weight, corrosion resistance, and ability to be molded into complex shapes.
ShimOuter Body Panel Repairs and Replacements: A shim is a thin metal piece used behind panels to bring them into alignment.
Shipping CoatOuter Body Panel Repairs and Replacements: A thin, temporary protective coating applied by the manufacturer to new sheet metal parts to protect the metal from corrosion during shipping and storage.
Shop LayoutSafety Precautions: Shop layout is the arrangement of work areas, storage, aisles, office, and other spaces in a shop.
Shop ToolMetal Finishing and Body Filling: A shop tool is a major tool that the shop owner usually provides, rather than one supplied by the individual technician.
Short-Hair Fiberglass FillerMetal Finishing and Body Filling: Short-hair fiberglass filler is a body filler reinforced with short chopped fiberglass strands that provides significantly greater strength and flexibility than conventional talc-filled polyester body filler, used for repairs in areas subject to vibration or stress.
Shrinking HammerMetal Finishing and Body Filling: A body hammer with a cross-grooved face used to compress stretched or work-hardened sheet metal back toward its original surface area by creating multiple simultaneous compression points.
Shrinking MetalMetal Finishing and Body Filling: Shrinking metal is the metalworking technique of reducing excess material in stretched or work-hardened sheet metal to restore the proper surface contour and eliminate the internal stress that causes panels to pop or flex after straightening.
Silicone-Treated Graining PaperPlastic Repair: Silicone-treated graining paper is a special paper used to create the final grain pattern in vinyl during upholstery repair.
Sill PlatesOuter Body Panel Repairs and Replacements: Sill plates cover the rocker panels and hold the edges of the carpeting -- also called scuff plates.
SledgehammerOuter Body Panel Repairs and Replacements: A sledgehammer is a heavy, long-handled hammer used in the early stages of collision repair to reform severely deformed thick-gauge metal parts, clear damaged metal during panel replacement, and apply heavy straightening force where lighter body hammers are insufficient.
Snap FitVehicle Systems Knowledge: A snap fit is a joining technique in which parts are forced over a lip or into an undercut retaining ring.
SnipMetal Finishing and Body Filling: A hand shearing tool used to cut sheet metal and other thin materials during collision repair.
Society Of Collision Repair Specialists (SCRS)Legal and Environmental Practices: SCRS is a collision repair industry trade association, named in the source material alongside other national organizations that serve the collision repair industry.
Socket WrenchOuter Body Panel Repairs and Replacements: A socket wrench is a tool system consisting of interchangeable sockets driven by a common handle (ratchet, breaker bar, or extension), allowing one handle to turn fasteners of many different sizes with speed and accessibility advantages over fixed-jaw wrenches.
Solder PaddleMetal Finishing and Body Filling: A solder paddle is a wooden spatula-type tool used for applying and spreading body solder.
SolderingMetal Finishing and Body Filling: Soldering is a joining process in which the base metal is heated enough to allow the solder to melt and form an adhesive bond.
Spanner SocketVehicle Systems Knowledge: A spanner socket is a specialty tool used for special applications, such as removing antennas, mirrors, and radio trim nuts.
Speed FileMetal Finishing and Body Filling: A speed file is a long holder used with strips of coarse sandpaper to smooth a work area.
Spontaneous CombustionSafety Precautions: Spontaneous combustion is a process in which material ignites by itself, without an external ignition source.
SpoonMetal Finishing and Body Filling: A spoon is a tool used in the same manner as a dolly, designed for use in confined areas and to pry panels back into position.
Spot Cutter BitWelding, Cutting and Removal: A spot cutter bit is a tool used to cut through the welds on a panel.
Spot WeldWelding, Cutting and Removal: A spot weld is a discrete weld joint produced by electric resistance welding, in which two overlapping metal panels are fused at a specific point by passing high current through electrodes that clamp and heat the metal at the contact area.
Spot Weld DrillWelding, Cutting and Removal: A spot weld drill is a specialized cutting bit designed to drill out factory resistance spot welds by removing the weld nugget from the top panel only, leaving the underlying panel intact for panel replacement procedures.
SpreadersMetal Finishing and Body Filling: Spreaders are flat, flexible or rigid plastic tools used to apply body filler, glazing putty, and similar compounds to damaged panel surfaces, spreading and shaping the material into a contoured coat before it hardens.
Spring-BackMetal Finishing and Body Filling: Spring-back is the tendency of metal to return to its original shape after deformation.
SqueegeeMetal Finishing and Body Filling: A squeegee is a flexible rubber pad or block used to apply glazing putty and light coats of body filler.
Squeeze-Type Resistance Inverter Spot WelderWelding, Cutting and Removal: A squeeze-type resistance inverter spot welder is the equipment type most manufacturers recommend for repairing high-strength steel, clamping and resistance-welding a spot joint with inverter-controlled current for the precision these steels require.
Squeeze-Type Resistance Spot Welding (STRSW)Welding, Cutting and Removal: The collision repair shop's equivalent of the factory spot welding process - an electric resistance welding technique in which high current is pulsed through layered metal panels held between the welder's electrode tips under controlled squeeze pressure, generating localized resistance heat that fuses the panels together at a discrete weld nugget without filler metal.
Standard ScrewdriverOuter Body Panel Repairs and Replacements: A standard screwdriver is a hand tool with a flat, single-blade tip designed to drive slotted (flat-head) screws, available in a range of blade widths and shank lengths to match specific fastener sizes.
Steering Column AssemblyGlass and Hardware: A steering column assembly is the tubular shaft and housing assembly connecting the steering wheel to the steering gear, incorporating the steering wheel, turn signal and wiper controls, horn and cruise control switches, and often the SRS air bag module.
Stitch WeldWelding, Cutting and Removal: A welding technique where short weld segments are placed at intervals along a joint and the gaps filled in after cooling, preventing heat buildup and metal distortion during long welds.
Stitch WeldingWelding, Cutting and Removal: Stitch welding is the use of intermittent welds to join two or more parts.
StoolsSafety Precautions: A stool is a low seat equipped with wheels.
Stretched MetalMetal Finishing and Body Filling: Stretched metal is sheet metal that has been deformed by impact forces so that its surface area has increased and its thickness has decreased, creating excess material that prevents the panel from returning to its original contour even after straightening.
Striker PinGlass and Hardware: A striker pin is the portion of the door lock mounted on the body pillar -- a bolt that can be adjusted laterally, vertically, fore and aft to achieve door clearance and alignment.
Stringer BeadWelding, Cutting and Removal: A stringer bead is a weld made by moving the electrode in a straight, continuous line.
StudVehicle Systems Knowledge: A stud is a headless bolt having threads on one or both ends.
SunroofGlass and Hardware: A sunroof is a vehicle roof having a panel that slides back and forth on guide tracks, or a transparent roof section that can be removed or slid into a recess.
Sunroof AssemblyGlass and Hardware: A sunroof assembly is the complete unit of glass panel, frame, drain system, motor and drive mechanism, seals, and related hardware that is factory-installed in the roof panel to provide an openable glass panel above the passenger compartment.
Supplied Air RespiratorSafety Precautions: A supplied air respirator is a respirator system that pumps clean, uncontaminated air from an external source into the mask, required for painters working with catalyzed paint containing isocyanates.
Support RodGlass and Hardware: A support rod is a metal rod that supports the head liner in a vehicle.
Surface RustOuter Body Panel Repairs and Replacements: Surface rust is the early stage of steel panel corrosion in which iron oxide (rust) forms on the outer surface of the metal without penetrating all the way through, leaving pits and reddish deposits that must be removed and treated before they progress to rustout.
Surface-Scratching MethodWelding, Cutting and Removal: The surface-scratching method is the technique of scratching an arc welding electrode across the work to form the starting arc.
Surfacing MatPlastic Repair: A surfacing mat is a thin fiberglass mat used as the outer layer when making repairs.
SurformMetal Finishing and Body Filling: A surform is a surface-forming grater file with open, rasp-like teeth.
Surform FileMetal Finishing and Body Filling: A Surform file is a tool used to shape body filler while it is semihard.
Synergic Pulsed TechnologyWelding, Cutting and Removal: Synergic pulsed technology is a welder feature that automatically presets and coordinates weld parameters using synergic curves, allowing aluminum welding with minimal setup or specialized training.
Syntactic FoamMetal Finishing and Body Filling: Syntactic foam is a resin and catalyst system containing glass or plastic spheres, used to fill rusted areas in door sills and rocker panels.

T

T-JointWelding, Cutting and Removal: A T-joint is a joint between workpieces meeting at right angles to form a T shape, with one piece meeting the face of the other.
Tab RepairPlastic Repair: A tab repair is an adhesively bonded or welded repair to a broken mounting tab on a plastic part, restoring the part's attachment point without replacing the entire component.
Tack WeldWelding, Cutting and Removal: A tack weld is a temporary weld used to hold parts in place during final welding operations, taking the place of a clamp or metal screw.
TapVehicle Systems Knowledge: A tap is a device used to cut internal threads, and to clean and rethread existing holes.
Tap And Die SetVehicle Systems Knowledge: A tap and die set is a set of tools used to restore damaged threads or to cut new threads -- taps for internal threads, dies for external ones.
Tapping TechniqueWelding, Cutting and Removal: The tapping technique is the momentary touching of an arc welding electrode to the work as a means of striking an arc.
Technical Service Bulletin (TSB)Preparation: A manufacturer-issued publication describing a known problem on a specific vehicle model/year along with the recommended fix, distinct from the general procedures in a service manual.
Temperature-Indicating CrayonWelding, Cutting and Removal: A temperature-indicating crayon is a temperature-sensitive crayon used to mark across a weld area to monitor its temperature.
Tensile StrengthVehicle Systems Knowledge: Tensile strength is the maximum force per unit of area a material can withstand before it fractures or breaks -- its resistance to being pulled apart.
Test WeldWelding, Cutting and Removal: A test weld is a practice weld made on scrap metal pieces that match the thickness and type of metal in the vehicle being repaired, used to verify and fine-tune welder settings and technique before welding on the actual vehicle.
Thermoplastic Polyurethane (TPU/TPUR)Plastic Repair: TPU, also written TPUR, is one of the plastic identification codes listed in the automotive plastics identification table, standing for thermoplastic polyurethane.
ThermoplasticsPlastic Repair: Plastics whose linear molecular chains soften and become workable when heated, then re-harden upon cooling - making them the most repairable class of automotive plastic, used in bumper covers, interior panels, and many exterior components.
Thermosetting PlasticsPlastic Repair: Plastics that are permanently cross-linked during manufacturing under heat and pressure; once cured they cannot be resoftened or reshaped by heat, and significant damage requires panel replacement rather than heat reforming.
Threshold Limit Value (TLV)Safety Precautions: An exposure guideline, similar to a PEL, representing the maximum airborne concentration of a substance a worker can be exposed to without expected harm.
TIGWelding, Cutting and Removal: TIG is an abbreviation for tungsten inert gas arc welding.
Tool ChestOuter Body Panel Repairs and Replacements: A tool chest is a large, roll-around cabinet used to store larger tools, typically with taller bottom drawers sized for bulky items like power tools.
Torque PatternVehicle Systems Knowledge: A prescribed crisscross or alternating tightening sequence for multiple fasteners that ensures a part is clamped evenly and prevents warpage from uneven loading.
Torque SpecificationsVehicle Systems Knowledge: Manufacturer-specified tightening values for individual fasteners that ensure correct clamp load without over-stressing the bolt or the assembled component.
Torque-to-Yield (TTY)Vehicle Systems Knowledge: A fastener design, often called a stretch bolt, that is intentionally tightened past its elastic limit during installation and must never be reused once removed.
Torx FastenerVehicle Systems Knowledge: A Torx fastener (also called a star fastener) is a six-point fastener that grips and drives without slippage, commonly used on late-model vehicles for luggage racks, headlights, taillight assemblies, mirror mountings, door strikers, seat belts, and exterior trim.
ToxicSafety Precautions: An EPA hazardous waste classification describing a material that leaches heavy metals at concentrations exceeding 100 times drinking water standards, requiring lawful disposal as hazardous waste.
Toxicity Characteristic Leaching Procedure (TCLP)Safety Precautions: An EPA test that determines whether a waste material will leach toxic chemicals into groundwater, which can reclassify borderline waste from hazardous to non-hazardous and reduce disposal costs.
Transmitter/Receiver Lock SystemGlass and Hardware: A transmitter/receiver lock system is a system in which a signal is transmitted from a small key ring transmitter to a receiver located in the vehicle to operate the locks.
Tungsten Inert Gas (TIG)Welding, Cutting and Removal: Gas-shielded tungsten electrode arc welding -- a precision welding process (also called GTAW) that uses a non-consumable tungsten electrode and an inert shielding gas to protect and control the weld.
Two-Part Adhesive SystemsPlastic Repair: Two-part adhesive systems are repair and bonding materials consisting of a base resin and a separate hardener that must be mixed at application to initiate a chemical cure, providing strong, durable bonds for plastic repair, panel bonding, and structural adhesive applications.
Two-Sided Tape AdhesiveOuter Body Panel Repairs and Replacements: Two-sided tape adhesive (double-sided tape adhesive) is a carrier tape coated with high-strength acrylic pressure-sensitive adhesive on both faces, used to permanently bond emblems, body side moldings, trim strips, and decorative components to painted vehicle surfaces.

U

Ultrasonic Plastic WeldingPlastic Repair: Ultrasonic plastic welding is a technique for repairing rigid automotive plastics in which welding time is controlled by a power supply -- the most commonly used airless welding method.
UndercutWelding, Cutting and Removal: An undercut is a groove melted into the base metal adjacent to a weld and left unfilled by weld metal.
UndercuttingWelding, Cutting and Removal: Undercutting is a MIG welding defect in which excessive travel speed causes the weld bead to be deposited in a narrow, low-profile bead that is lower than the surface of the surrounding base metal, creating a notch or groove along the weld edges that weakens the joint.
United States Customary System (USCS)Vehicle Systems Knowledge: The United States Customary System, or USCS, is the fractional measuring system in which fastener head size and wrench size are both expressed as fractions rather than as metric numbers.
UpholstererGlass and Hardware: An upholsterer is a specialist whose expertise is the repair or replacement of interior surface materials.
Upholstery Ring PliersGlass and Hardware: Upholstery ring pliers are pliers used to remove or install upholstery rings.
UpsettingMetal Finishing and Body Filling: Upsetting is the deformation of metal under compression.
Utility KnifeMetal Finishing and Body Filling: A utility knife is a hand-held cutting tool having a replaceable, retractable blade.

V

Vacuum Cup PullerMetal Finishing and Body Filling: A vacuum cup puller is a large suction cup used as a dent puller.
Vehicle Lift PointsSafety Precautions: Vehicle lift points are the specific structural locations on the frame, subframe, or unibody pinch welds designated by the vehicle manufacturer as the only safe locations for positioning jack stands, floor jacks, or vehicle lift pads when raising a vehicle.
Vertical WeldingWelding, Cutting and Removal: Vertical welding is a welding position in which the weld joint runs vertically and the weld is deposited upward or downward along the joint, requiring adjusted technique to counteract the effect of gravity pulling the molten weld pool away from the joint.
VinylPlastic Repair: Vinyl is a class of material that can be combined to form vinyl polymers used to make chemical-resistant finishes -- and as a soft, flexible, thin plastic often applied over foam filler for dash pads and armrests.
Vinyl-Coated FabricsPlastic Repair: Vinyl-coated fabrics are materials with a plastic protective or decorative layer bonded to a fabric base that provides strength.
Vise-GripsOuter Body Panel Repairs and Replacements: Vise-Grips (locking pliers) are adjustable, self-locking pliers that clamp onto a workpiece and lock in place - used in collision repair to hold panel flanges together for welding, grip rounded fasteners, clamp damaged components during pulling operations, and maintain panel alignment during repairs.
VOCLegal and Environmental Practices: VOC is an abbreviation for volatile organic compound -- a material that vaporizes easily.

W

Water LeaksGlass and Hardware: Water leaks are intrusions of water into the vehicle interior through gaps, failed seals, or improper weatherstripping around doors, windows, glass, body seams, or body plugs, located by water spray testing, light leak inspection, or listening device methods.
WeatherstrippingGlass and Hardware: Weatherstripping is a flexible rubber or foam seal that runs around door openings, trunk lids, hood edges, and window frames to create an airtight and watertight seal when the panel is closed, preventing water leaks, air leaks, and wind noise.
Weave BeadWelding, Cutting and Removal: A weave bead is a wide weld bead made by moving the electrode back and forth in a weaving motion.
WeldWelding, Cutting and Removal: A weld is the joining of two metal or plastic pieces by bringing them to their melting points so they fuse together.
Weld BeadWelding, Cutting and Removal: A weld bead is the seam of deposited metal between workpieces that have been joined by welding.
Weld BondingWelding, Cutting and Removal: A hybrid joining process that combines structural adhesive with resistance spot welding (STRSW) or MIG plug welding, producing a joint that is stronger, stiffer, and more corrosion-resistant than either method alone.
Weld FaceWelding, Cutting and Removal: The weld face is the visible outer surface of a completed weld bead on the side from which the weld was made, including the face reinforcement (convex buildup above the base metal surface) and the toe (the line where the weld face meets the base metal).
Weld InsertsWelding, Cutting and Removal: Small metal backing pieces fitted behind or inside box sections and hollow structural areas to support the joint, improve alignment, and strengthen the weld during structural body repair.
Weld LegsWelding, Cutting and Removal: The width and height dimensions of a fillet weld bead, defining the size of the weld contact area on each of the two joined surfaces.
Weld PenetrationWelding, Cutting and Removal: Weld penetration is indicated by the height of the exposed surface of a weld on the back side of the joint.
Weld RootWelding, Cutting and Removal: The weld root is the depth of the triangular cross section of a weld, at the part of the joint where the electrode is directed.
Weld ThroatWelding, Cutting and Removal: The depth of the triangular cross-section of a fillet weld, measured from the root of the joint to the face of the bead, which determines the shear strength of the weld.
Weld-Through PrimerWelding, Cutting and Removal: A specialized primer applied to bare metal surfaces in weld zones before welding to provide corrosion protection at joint areas that will be permanently inaccessible after the repair is closed.
WeldingWelding, Cutting and Removal: A metal-joining process that uses extreme heat to fuse pieces of metal together, categorized as resistance spot welding, fusion welding, or braze welding in automotive body repair.
Welding BlanketSafety Precautions: A fire-resistant covering placed over vehicle interior components during welding and cutting operations to protect them from heat, sparks, and molten metal splatter.
Welding CurrentWelding, Cutting and Removal: The amperage setting on a MIG welder that controls arc penetration depth, wire melt rate, arc stability, and bead geometry, and must be matched to material thickness to avoid burn-through or cold lapping.
Welding Filter LensSafety Precautions: A shaded glass or polycarbonate insert in a welding helmet that blocks ultraviolet and infrared radiation from the arc, graded by shade number from 4 (lightest) to 12 (darkest).
Welding HelmetSafety Precautions: A full-head protective device with a shaded filter lens that shields the face, neck, and eyes from heat, molten metal spatter, and harmful radiation produced during all electric welding operations.
Welding RespiratorSafety Precautions: A respiratory protective device with specialized metal fume filter cartridges that remove toxic welding fumes from inhaled air, especially critical when welding zinc-coated steel.
Wind CordGlass and Hardware: Wind cord is a rope-like trim placed around door openings to help seal and decorate them.
Wind LaceGlass and Hardware: Wind lace is a rope-like trim placed around doors to help seal and decorate the openings -- another term for wind cord.
Wind NoisesOuter Body Panel Repairs and Replacements: Wind noises are high-frequency swishing sounds heard when the vehicle is being driven.
Window ChannelGlass and Hardware: A window channel is the grooves, guides, or slots in which the glass slides up and down or back and forth.
Window RegulatorGlass and Hardware: The mechanical assembly inside a door that raises and lowers the window glass, available in manual (hand-crank) and power (electric motor-driven) versions.
Window StopGlass and Hardware: A window stop is a device inside a door used to limit glass height and depth.
Wire-Feed SpeedWelding, Cutting and Removal: Wire-feed speed is the rate at which a GMAW welder feeds electrode wire into the weld, a core tuning setting that must match voltage, polarity, and flow rate for the substrate being welded.
Work HardeningMetal Finishing and Body Filling: Work hardening is metal becoming stiffer and harder in stretched or bent areas due to permanent stresses -- the upper limit of plastic deformation, causing the metal to become very hard in the worked area.
Workplace Hazardous Materials Information System (WHMIS)Safety Precautions: Canada's workplace hazard communication system, which (like its U.S. OSHA counterpart) requires mandatory hazard warnings on supplier product labels.
Wrench SizeMetal Finishing and Body Filling: Wrench size is determined by the width of the jaw opening of a wrench.

Z

Zoning OrdinanceLegal and Environmental Practices: A zoning ordinance is the law that limits the type of businesses allowed in a particular area or zone.

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