What Tesla Requires for Rivets and Structural Adhesive, and Why Ford, GM and Stellantis Answer It Differently

A clip went around the shops this month worth stopping on. A technician is setting flow form rivets into a quarter panel on a Tesla, and the top comment underneath it is not praise. It is another technician saying, roughly, I hope you are not the one who leaves panel bond smeared all over the rivet gun, because we have a guy like that and the gun has never worked right since.

That is the modern panel attachment problem. The rivet is not the hard part and the adhesive is not the hard part. The hard part is that the two go together in a specific order, with a specific tool and a specific fastener, and almost nobody learned it the way they learned to run a spot welder.

I teach this at Sheridan Technical College, and Tesla exposes the gap faster than any other brand. It publishes more hard numbers about fastening than most shops are used to reading, and very few of them match what a technician picked up on a Ford.

Why the Spot Weld Went Away

Twenty years ago a unibody was mostly mild steel and you attached lapped panels with resistance spot welds. Then material strength went up, aluminum arrived on volume vehicles, and mixed-material bodies put aluminum panels on steel structures that cannot be welded together. Heat became the enemy of the metal you were trying to save.

The answer was mechanical fasteners plus structural adhesive. Ford says it plainly: adhesives and mechanical fasteners are used in all areas of the body structure in place of welding, and besides bonding the components they help prevent wind noise, water leaks, exhaust fumes and dust from entering the vehicle and provide an anti-corrosion barrier. Scrape that off a flange and fail to replace it, and four functions leave the car at once.

Tesla's Fastener Menu Is a Closed List

Tesla names eleven categories approved for structural repair: standard rivets, countersunk rivets, the structural bulb rivet, the structural flange rivet, Self-Piercing Rivets (SPRs), flow form rivets, blind oversize mechanically locked fasteners (BOMs) and 8 mm structural rivets, NeoBolts with AVBolts and Huck Bobtail fasteners, pin and collars, bolts and nuts, and rivet nuts and studs. Each has a part number and a symbol printed on the repair illustration.

The warning attached is worth reading twice. Tesla says using non-approved fasteners might compromise the integrity of the repair and vehicle safety, and might also affect whether Tesla supports the vehicle. That is a maker telling a shop the car's standing depends on what came out of the fastener drawer.

Some rules are ones a technician will not guess. SPRs are designed for stacks of three panels or fewer, and wherever possible the SPR goes through the thinner panel first. Even the gun has a floor: rivet guns used in Tesla repair procedures must have a pulling force of at least 14,000 newtons (3,000 pounds force). Source: Tesla, 2025+ Model Y L Collision Repair Procedures, Approved Fasteners and Fastener Tools for Structural Repairs.

Flow Form Rivets: The Procedure in Full

This is the fastener Tesla leans on hardest, and the clearest example of how specific the work has become. Tesla allows flow form rivets as an alternative to SPRs in any Tesla structural repair procedure that specifies SPRs, including where there is no longer enough room for an SPR because panels have been previously replaced. For areas likely to see repeat repairs, flow form rivets also avoid creating additional holes in the body panel.

Selection is a measurement, not a judgment call. Every approved flow form rivet has an 8 mm body diameter and only the length changes. Measure the panel stack with a caliper and find the rivet whose grip range contains that number. Tesla publishes seven: S08 at 1.3 to 2.5 mm, S18 at 2.3 to 3.5 mm, S28 at 3.35 to 4.10 mm, S38 at 4.0 to 5.15 mm, S48 at 5.0 to 6.1 mm, S58 at 6.0 to 7.2 mm and S68 at 7.1 to 8.3 mm. Those ranges deliberately overlap, and Tesla answers that too: when the stack falls inside two of them, use the longer rivet.

The hole is 8 mm, punched with a riveter built for it or drilled with an 8 mm bit, and a drilled hole must be deburred before the rivet goes in. That is the line I see skipped most often, and a burr under a flow form rivet is a gap in a joint meant to be metal to metal.

Then the tool. Tesla names the approved riveters and the pressure each sets at: the Wieländer and Schill XPress 800 at 60 kilonewtons, the TKR PNP 90 UN 2.0 and PNP 90 XT squared at 60 kilonewtons, the ProSpot PR-5 at 50 kilonewtons and the Böllhoff HTF 50 SPR Tool at 50 kilonewtons. Dies are paired to rivet size, not chosen by feel: on the XPress and TKR tools an S08 or S18 uses a C5 holding die with a C4 forming die, while an S28 through S68 uses a C3 holding die with the same C4. The same table and hole size appear in the 2020 to 2024 Model Y Structural Pack manual, so this is platform-wide, not one car's quirk. Source: Tesla, Using Flow Form Rivets, both manuals.

Tesla's Hole Sizes, and the SPR Die Nobody Should Guess

Tesla publishes a hole size for every fastener it approves, and the numbers are not round. A 4.8 mm blind rivet gets a 4.9 mm hole, a 6.5 mm blind rivet gets 6.7 mm, a flow form rivet gets 8 mm. An aluminum plug weld hole is 9 mm and only for panels up to 1.6 mm thick, while a steel plug weld hole is 6 mm and only for panels up to 1 mm thick.

On SPRs, Tesla is blunt: use the die indicated in the repair procedure, because an incorrect die might result in premature component separation. The procedure names a Böllhoff die, and Tesla publishes a conversion table so a shop running another approved tool finds the matching die rather than improvising. Removal has rules too: when drilling completely through an SPR, Tesla says not to use a bit larger than the hole size specified for the replacement fastener.

Tesla's Approved Chemicals Are a List of Three

For structural repair on a Tesla, three structural adhesives are approved: DuPont BETAMATE 2098 Crash Durable Structural Adhesive, Parker LORD Fusor 2098 in the slow version for North America, and 3M Impact Resistant Structural Adhesive 07333. That is the whole list. Source: Tesla, 2025+ Model Y L Collision Repair Procedures, Approved Chemicals.

Three warnings sit around it. Do not use a non-approved structural adhesive. Never use expired adhesive. And do not use structural adhesive as a substitute for welds, rivets or any other fastening method listed in a Tesla body repair procedure unless that procedure directs it. The counterweight is that, unless the procedure says otherwise, adhesive goes on all non-welded mating surfaces and all panels being replaced. It is everywhere on the joint and is never the joint by itself.

The Surface Prep Step That Will Trip a Ford Technician

Here is the biggest habit break in this article. On a Ford rivet-bonded joint you remove the old adhesive and the electrodeposition primer from the mating surfaces of both the original part and the replacement, 25 mm on each, at 80 to 125 grit, the range Ford names as giving the best adhesion. You take it to clean metal.

On a Tesla non-welded bonded joint, you do not. Tesla says to abrade the electrodeposition coating with a red abrasive pad or equivalent, and that it is not necessary to remove the coating completely, only to roughen it so the adhesive can grip. It pushes the other way as well: to avoid galvanic corrosion, do not remove the coating anywhere steel and aluminum will be in contact. Two makers, two opposite instructions, both correct for their own vehicle. A technician who sands a Tesla bond flange to bare metal out of Ford habit has removed the corrosion barrier the engineer counted on.

The cleaning rule is equally particular. Clean every mating surface with isopropyl alcohol, then wipe the remainder off immediately with a clean dry towel, because letting it air dry can compromise the bond. Bare metal exposed two hours or longer is abraded and cleaned again.

The bead technique is spelled out too, and it is not the single fat bead most people run. Apply a bead on the vehicle and smear it. Apply a bead on the replacement component and smear it. Then apply one new bead on top of the smeared adhesive of either the vehicle or the component, and Tesla is explicit that you do not put it on both.

Tesla's Heat, Clamp and Weld Limits

A bonded panel on a Tesla must not be heated above 212 degrees Fahrenheit (100 degrees Celsius) unless that panel is being removed, because heating the adhesive past that point can weaken the bond and compromise crash integrity. Ford allows heat not exceeding 425 degrees Fahrenheit (218.3 degrees Celsius) to loosen a rivet-bonded panel, and only when every panel in that joint is being replaced or separated. Stellantis, in the Ram 1500 collision information, accepts up to 400 degrees Fahrenheit (204 degrees Celsius) from a non-open-flame source such as a heat gun. Three makers, three ceilings, the lowest less than half the highest.

Tesla sets limits most shops have never measured. After the component is secured there must be no structural adhesive within 25 mm of any gas metal arc weld location, because adhesive in the weld zone can cause weld failure, and the adhesive must be dry to the touch before welding starts. Within 200 mm (8 inches) of a resistance spot weld only insulated clamps may be used, and that welding must finish before the adhesive cures, so the clock on the adhesive is the clock on the job.

Two more are specific to an electric car. Do not weld on a Tesla before performing the vehicle electrical isolation procedure, and when force curing adhesive near the high voltage battery, do not let the battery exceed 74 degrees Celsius (165 degrees Fahrenheit). Only technicians who have completed Tesla's approved welding training may weld structural components.

What the Casting Changes About Repair Versus Replace

Tesla's cast underbody is why its attachment rules read differently from everyone else's. A casting is not a weldment you can section wherever you like, so Tesla maps the part by color, with a different answer in each zone.

On the cast front under body in the Model Y Structural Pack manual, broken tabs can be welded back into place and bent tabs straightened cold. In the green zones, welding damage up to 50 mm is allowed. In the yellow zones, welding up to 30 mm is allowed with no reinforcement and 30 mm to 50 mm only if reinforcement plates go in with it. In the orange zones a crack up to 30 mm can be welded but a reinforcement plate is required. In the red zones there is no repair at all, and damage crossing a zone boundary is not repaired without Tesla's prior approval.

The reinforcement plate ties this back to adhesive. Tesla states those plates are not installed by welding, only with structural adhesive, placed on both sides of cracked or straightened webbing and clamped. It also warns that because the plate increases panel stack thickness, a later repair putting fasteners through it may need different fasteners, which is the grip range problem showing up months later. Bent webbing is straightened cold only and restored to within 1.5 mm of its original position. Source: Tesla, Model Y Structural Pack Collision Repair Procedures, Cast Front Under Body Repair Guidelines.

Then the limit that catches body shops hardest: Tesla does not support pulling or pushing any component with frame straightening equipment, because it can damage a component or a joint, including fasteners and adhesive, in seemingly unrelated parts of the structure. Tension towers are allowed only on the exterior panel of the hood, trunk, door, fender and liftgate.

Where Tesla Simply Says No

A damaged part with a crash sensor attached is replaced, not repaired. If any factory adhesive bond is compromised, the panel is replaced. Ultra High-Strength Steel (UHSS) components are not repaired unless the part repairability guidelines explicitly allow it, and UHSS is not used as a backing plate unless the manual says so.

The materials table behind those rules is worth knowing for the ASE B4 as much as for the bay. Tesla puts 5xxx series aluminum at a yield strength of 100 to 150 megapascals and 6xxx at 230 to 280, mild steel under 270 megapascals tensile, High-Strength Steel at 300 to 700, and UHSS above 800. Maximum heat on any aluminum grade is 212 degrees Fahrenheit (100 degrees Celsius). On mild steel and High-Strength Steel it is 1200 degrees Fahrenheit (650 degrees Celsius), twice at most, under 90 seconds total. On UHSS, heat repairs are not approved.

The Other Four Makers, Side by Side

Ford. The replacement path is a number. If an SPR is installed during a repair it must be placed adjacent to the original, and if no adjacent area is available, a solid rivet or a blind rivet is used after enlarging the hole to 6.5 mm. A removed Flow Drill Screw, which Ford calls a manufacturing-only one-use fastener, leaves a hole that is also enlarged to 6.5 mm. Ford states all body fasteners are made of boron and carry a special coating against galvanic corrosion, does not authorize aftermarket structural rivets of any kind on vehicles with aluminum structural and cosmetic body components, and publishes the riveting systems it has validated.

General Motors. The use of adhesive to section steel panels is not recommended by General Motors, and bonding procedures in general apply only at factory joints. Adhesive-only joints exist only where there is no way to introduce a spot weld, a rivet or another mechanical fastener, and are always named in a specific procedure.

Stellantis. It does not approve or endorse structural adhesives alone to replace body panels, and says structural adhesive should not be used in a joint that did not originally contain it. Gas Metal Arc Welding (GMAW) is not recommended within 25 mm (1 inch) of adhesive because the heat destroys it, while Squeeze Type Resistance Spot Welding (STRSW) can weld through adhesive without destroying its properties. Stellantis also lists weld-through primers as not recommended. That contradicts Tesla directly: on a steel backing plate at a Tesla butt joint, Tesla tells you to apply weld-through primer to both sides, let it cure, then sand it off the outboard surfaces only at the weld locations.

Honda. The CR-V body repair information gives a bead size most makers do not publish: when adhesive is applied continuously, apply a bead with a diameter greater than 3 mm (0.12 inch), and apply the same number of spot welds as the mass production body. Honda also says not to apply adhesives near Metal Active Gas or Metal Inert Gas braze welding, because the adhesive may ignite and burn.

When two makers disagree they are not disagreeing about physics, they are disagreeing about their own vehicle, and only one of them is on your lift. That is the hierarchy we cover in recommended practices versus OEM procedures.

The Aluminum Isolation Requirement Nobody Budgets For

Galvanic corrosion happens when dissimilar metals stay in contact and the more reactive metal becomes a sacrificial anode, so working steel and aluminum in one space raises the risk for both. Ford calls for an isolation area dedicated to aluminum repair, with a wet mix vacuum and air filtration pulling the sanding dust and tools dedicated to aluminum. Tesla makes the same point from the other end, warning against using the same equipment to remove epoxy from aluminum and from steel, and limiting aluminum to 80 grit or finer because anything coarser can fracture it.

A legal floor sits underneath that. Under the Occupational Safety and Health Act of 1970, section 5(a)(2), 29 U.S.C. 654(a)(2), an employer must comply with the standards issued under the Act, and 29 CFR 1910.94(b) requires local exhaust ventilation wherever dry grinding, dry polishing or buffing is performed and employee exposure exceeds the limits in 29 CFR 1910.1000. That is an exposure-based ventilation requirement, and it does not by itself name aluminum dust or mandate a wet collector. Source: osha.gov.

What Actually Goes Wrong in the Bay

Adhesive on the rivet gun. That comment under the Tesla video was not a joke. Structural adhesive cures hard, and on a setting tool it changes how the dies seat. Tesla's install sequence ends by cleaning adhesive off the panel and off any equipment contaminated during installation.

The wrong mandrel. Ford says each SPR requires a specific mandrel, and the mandrel sets the depth and spread. A rivet driven to the wrong depth looks finished and is not.

Prepping the flange the way the last car wanted. Ford says bare metal at 80 to 125 grit across 25 mm. Tesla says roughen the coating and leave it. Same discipline as substrate prep after metalwork, and it fails the same way: slowly, invisibly, after the car leaves.

How This Shows Up on the ASE B-Series

The ASE B3, Non-Structural Analysis and Damage Repair, covers panel attachment methods, corrosion protection and restoring the factory joint. Expect questions that describe a removed fastener and ask what goes back. The ASE B3 study guide walks those content areas.

The ASE B4, Structural Analysis and Damage Repair, covers sectioning, joint selection and the authority question. Expect Technician A and Technician B items where one proposes a reasonable-sounding substitution and the other says to pull the procedure. The procedure answer wins, and the most-missed ASE B4 topics article covers the pattern.

A third connection catches people out, and the electric cars make it worse. Replacing a quarter panel, a bumper reinforcement or a pillar can move a radar or camera mounting position, which triggers a calibration requirement with its own line on the estimate. That is ASE B5 territory.

The Short Version

Rivets and adhesive did not replace welding because they are easier. They replaced it because the metal changed and heat became the enemy.

On a Tesla the chain is published and closed: approved fasteners, approved tools at a named pressure, dies paired to rivet length, three approved adhesives, a grip range measured with a caliper, an 8 mm deburred hole, coating roughened rather than removed, nothing adhesive within 25 mm of a gas metal arc weld, and no heat over 212 degrees Fahrenheit on a bond you keep. Ford, General Motors, Stellantis and Honda answer the same questions with different numbers, and each is right about its own car.

Pull the procedure, and read it before teardown rather than after you are committed. That habit is the difference between a repair that holds up and one that comes back, and it is the habit the ASE B3 and ASE B4 are built to reward.