Will your compressor keep up?
Spraying is the most air-hungry thing in the shop. Pick your gun and compressor to see if the air supply can feed it through a full coat.
Flash-off time calculator
Your product data sheet (TDS) lists a flash-off time at a standard temperature. A cold, hot, or humid booth changes how fast the paint actually flashes. Enter your booth conditions and the TDS time (a single time like 10, or a range like 5-10) for an adjusted estimate.
Spray gun types
The gun cap technology decides transfer efficiency (how much paint lands on the panel) and how much air it drinks. HVLP and RP are the modern, VOC-compliant choices.
| Type | Air demand | Best for |
|---|
Feed style: gravity (cup on top, most common today), pressure (remote pot, for production), or siphon (cup below, older). Dedicate guns when you can: one for base, one for clear, one for primer, plus a small detail/jamb gun. Mixing clear residue into base is a common defect cause.
Air compressors
The spec that matters is CFM at 90 PSI (continuous air delivery), not horsepower. Two-stage piston is the body-shop standard; rotary screw runs 100% duty for booths. Most real shop units need 220V.
| Compressor | CFM @ 90 PSI | Notes |
|---|
Rule of thumb: a piston compressor should deliver about 1.5 times your gun's CFM so it is not running nonstop (that headroom covers the duty cycle plus a blow gun or sander running at the same time). A rotary screw makes air continuously, so it can run closer to the gun's number.
Air tools (and why size matters)
These run off the same compressor as the gun. In a busy shop several run at once, so size the air supply for everything running together, not just the gun. A single 6 inch DA sander can out-drink a spray gun.
| Air tool | Air demand | Notes |
|---|
Why it adds up: if a painter sprays an HVLP gun (about 13 CFM) while someone else runs a 6 inch DA sander (about 15 CFM) on the next car, the compressor has to deliver roughly 28 CFM at once. Size for the busiest moment, not the average. Use the toggles in the calculator above to add tools and watch the air demand climb.
The air system between the two
Clean, dry air is the difference between a glass-smooth clear and a panel full of fisheyes. The compressor is only half the job.
Air dryer / desiccant
Moisture and oil cause fisheyes and blush. A refrigerated dryer or desiccant column plus a coalescing filter at the gun is essential for paint.
Filters & regulator
A wall-mount filter/regulator plus a small inline desiccant and gauge right at the gun. Set the gun inlet pressure with the trigger pulled.
Air line sizing
Undersized line starves the gun. Use larger main lines (loop the shop if you can), slope to drain legs, and keep hose runs short and at least 3/8 inch ID.
Tank & drain
A bigger tank smooths demand spikes. Drain condensate daily (or add an auto-drain) so water never reaches the gun.
The rest of the shop
Round out the setup so you can actually turn out clean work.
PPE & respirator
Pick the right respirator and cartridges for your work with the PPE Selector. Spraying 2K clear needs supplied air.
Prep & booth
A prep station or booth with good airflow and filtration, plus a way to bake or force-dry. Even a curtained area beats open-shop spraying.
Color-match lighting
Daylight-balanced (5000K) color-matching lights. You cannot judge a blend under yellow shop lights.
Mixing bench
A clean mixing area with a gram scale, mixing cups/sticks, and your paint maker's ratios. Accuracy here prevents most defects.
Sanding & abrasives
A DA sander with vacuum, a range of grits, blocks, and a tack/prep system. Dust control protects the finish and your lungs.
Hand tools & PPE gear
See the Pro Gear page for the guns, sanders, PPE, and supplies your instructor recommends.