Painting a Car Is a Process

Painting a car is a process, and every step matters. Rushing prep work is the #1 reason paint jobs fail. Follow these seven steps for a professional result — and keep the cheat sheet and the technical data sheets handy while you work.

Step-by-Step: How to Paint Your Car

Strip or Sand the Existing Finish
Remove loose paint, rust, and imperfections. If the existing finish is in good shape, scuff it with 320–400 grit sandpaper to give the new primer something to grip.
Shop OptiGrit abrasives →
Body Work
Fill dents, dings, and imperfections with polyester body filler. We recommend TrueFill Polyester Filler — mix with 2% hardener by weight, and you'll have about 6–7 minutes of working time. Shape with P80–P120 grit, then finish-sand with P120–P280.
Shop TrueFill body filler →
Block Sanding
This is where the magic happens. Block sanding creates a perfectly smooth surface. Use our Linear Blocking Boards:
- Rigid — for flat panels (doors, hoods, roofs)
- Semi-Flex — for slight contours (fenders, quarter panels)
- Ultra-Flex — for complex curves (bumpers, body lines)
Use a cross-hatch sanding pattern for the most even results.
💡 Not sure which block size you need? Watch the short sizing guide below.
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Primer / Sealer
Primer creates the foundation your paint sits on. You have three great options:
Epoxy Primer AP-5021 (NEW) — Primer filler mode: mix 2:1 with AH-5100 activator (no reducer). Sealer mode: mix 2:1 + 25% urethane reducer. Primer filler: 2–3 full coats, dry to sand in 8 hours. Sealer: 1 wet coat, topcoat after 45 minutes. Best for bare metal, galvanized steel, aluminum, fiberglass, rigid plastics — a versatile 2-in-1.
HS Epoxy Primer/Sealer (AP-5511) — Mix 1:1 with AH-5200 hardener. Apply, then topcoat wet-on-wet after 30–45 minutes at 68°F. Best for bare metal, full restorations, maximum adhesion.
DTM Primer-Sealer (AP-7541) — Primer mode: mix 4:1:1 (primer : activator : reducer) for high-build. Sealer mode: mix 4:1:2 for a thinner sealing coat. Topcoat wet-on-wet after 15–20 minutes. Best for over existing finishes and quick panel repairs.
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Basecoat
This is your color. Most Alpha Automotive Basecoat is sold ready to spray (pre-reduced) — no reducer or mixing needed, spray it as supplied. If you bought it unreduced, mix 1:1 with Alpha Urethane Reducer.
Apply 2–3 medium wet coats with 5–15 minutes of flash time between coats at 68°F. If you need to recoat after 8+ hours, lightly sand with 600–800 grit first.
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Clearcoat
Clear protects your color and gives it that deep, glossy shine. Apply 2 full coats with 8–10 minutes flash time between coats. Not sure which clear to use? See the clearcoat guide.
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Wet Sand & Polish
After the clear has fully cured, wet sand with 1500–2000 grit, then polish with compound and finishing polish for a mirror-like showroom finish.
Deep dive: See our full Wet Sanding & Polishing Guide for the complete step-by-step process, grit progression, and common mistakes to avoid.
Wet sanding & polishing guide →