To sand car paint, clean, mask, step through 80–400 grit dry, prime, wet-sand 600–1500, then polish or repaint as needed.
If you want a smooth, paint-ready surface, you need a clear plan, the right abrasives, and a steady pace. This walkthrough gives you the full process—from first scuff to final polish—so you can finish panels that lay flat, accept primer, and shine when cleared. You’ll see where each grit fits, when to switch from dry to wet, and how to avoid risky moves that chew through clear coat. This guide shows you how to sand car paint with shop-tested sequences and plain steps that anyone can follow.
How To Sand Car Paint: Clean, Prep, And Work In Stages
Start with safety, then move through staged sanding. Each pass removes the scratches from the last one. Skip a step and you chase deep marks later. Follow this order and you’ll save time and materials.
| Task | Typical Grit Range | Goal |
|---|---|---|
| Strip failing paint or heavy texture | 80–120 | Cut old layers fast without gouges |
| Shape body filler | 80–180 | Flatten highs, set panel contour |
| Feather old paint edges | 220–240 | Blend edges so steps disappear |
| Final filler refine | 220–240 | Knock down scratches before primer |
| Primer surface prep | 320–400 | Uniform tooth for adhesion |
| Wet-sand before basecoat (if sealing) | 600 | Smooth primer or sealer |
| Level clear coat runs or dust | 1000–1500 | Flatten defects with control |
| Final refining before polish | 2000–3000 | Leave fine haze that buffs out |
Sanding Car Paint The Right Way: Step-By-Step
Gear Up And Protect The Work Area
Wear eye protection, gloves, and a rated respirator for dust. A vacuum-ready sander or dust-extracting blocks keep the air cleaner and the paper cutting longer. Lay masking paper and plastic sheeting to stop grit from drifting onto fresh finishes. Good lighting helps you spot low spots and scratch patterns fast.
Wash, Degrease, And Mask
Grit sticks to clean panels better than dirty ones. Wash with car shampoo, rinse, then wipe with a wax-and-grease remover. Dry fully. Mask gaps, glass, trim, and panel edges you don’t want to touch. Pull weatherstrips back with tape to expose hidden edges.
Knock Down Old Layers Or Texture
Use 80–120 grit on a DA sander to remove thick peel, failing clear, or old repaints. Keep the pad flat. Work in cross-hatch passes. Don’t linger on crowns or edges; they burn through fast. Vacuum the surface between passes so the abrasive stays sharp.
Shape And Refine Body Filler
After filler cures, shape with 80–120 grit on a block until the contour matches the panel. Switch to 150–180 to refine. Keep strokes long and straight. Short, choppy motions will dish the area. Use a dry guide coat to reveal low spots and stray scratches.
Feather The Surrounding Paint
Feather sanding blends the edge where repaired area meets original paint. Sand the halo around the repair with 220–240. You’re aiming for a smooth transition that you can’t feel with a fingertip. If you can feel a step, the primer will reflect it later.
Prep For Primer
Extend your sanded zone with 320–400. The goal is a uniform scratch that gives primer grip. Blow off dust, wipe with solvent, and re-mask sharp. Spray high-build primer per the product sheet. Flash times matter; rushing traps solvents and can sink later.
Block Sand The Primer
Once cured, hit primer with 400 dry on a long block to level minor waves. Re-apply guide coat and sand until the color haze is gone. Deep scratches that survive this step need spot putty or a local re-prime. Don’t chase them with super fine paper yet; you’ll only round the area.
Safety, Dust Control, And Paint Thickness
Dust from sanding can travel far. A vacuum sander and local exhaust drop the cloud and keep your shop safer. A tight-fitting respirator filters what’s left. If you have a paint thickness gauge, take readings before you wet-sand clear. Factory finishes can be thin, and you only get so many correction cycles.
For deeper reading on safe shop setup, see the OSHA page for autobody hazards and solutions. For grit choices by task, 3M’s refinish article on proper grit selection gives helpful ranges.
When To Switch To Wet-Sanding
Wet sanding cuts slower and flatter, which is perfect for refining primer, sealer, and clear coat. Dry sanding builds dust but cuts fast and shows scratches clearly. Switch to wet once you’re out of the heavy-removal phase.
Set Up For Wet Work
Use fresh water with a splash of car shampoo in a spray bottle. Soak sheets of 600, 1000, 1500, and 2000 for ten minutes. Use a soft interface pad or a rubber block to keep pressure even. Paper folds or fingertip pressure will print lines you’ll chase later.
Refine Primer Or Sealer
After primer blocks flat with 400 dry, move to 600 wet. Sand in straight passes with light pressure. Keep the surface wet and wipe sludge often. When the panel feels smooth and looks uniform, you’re ready for basecoat or sealer.
Level Runs, Nibs, And Texture In Clear
Knock the peak off a run with a nib file or a crisp, hard block backed with 1000. Then step to 1500 and 2000 until the defect blends into the field. Stay off body lines and edges, or tape them for protection. Those areas lose clear fastest.
How To Sand Car Paint Without Burn-Through
Edges are thin. So are panel crowns and body lines. Tape these spots or float the block past them. Keep fresh paper on the tool; dull grit needs more pressure and that triggers burn-through. If you hit color while leveling clear, stop and plan a spot repair.
Common Sequences That Work
The exact flow depends on the starting point. Here are sample paths you can tailor to your panel and product sheet.
| Starting Point | Grit Path | Finish Before Next Step |
|---|---|---|
| Old clear with peel | 120 → 180 → 240 → 320 → 400 | Prime |
| Fresh body filler area | 80 → 120 → 180 → 240 → 320 | Prime |
| Primed repair | 400 dry → 600 wet | Basecoat/sealer |
| Dust nibs in clear | 1500 → 2000 → compound | Polish |
| Run in clear | 1000 block → 1500 → 2000 | Polish |
| Blend edge prep | 240 feather → 320 | Prime |
| Orange peel after respray | 1500 → 2000 → 3000 | Compound |
Block Choice, Motion, And Pressure
Use a long block on broad, flat doors and quarters. Use a curved block on profiles. Soft foam helps on bumpers and plastic. Keep passes straight and overlapping. Let the abrasive do the work. If the paper quits cutting, swap it—heat and pressure distort panels and smudge primer.
Guide Coat: Your Scratch Map
Dry guide coat is cheap feedback. Dust it on, sand, and watch the highs and lows appear. If black specks linger in low spots, you’re not flat yet. Re-coat and go again. Don’t jump to finer grit until the guide coat clears; fine paper won’t fix deep marks.
Dealing With Thin Paint
Factory finishes vary, but many sit near 100–125 microns total. Repaints can be thicker. If readings are low, skip aggressive steps on edges and shift more work to compounds and pads. You can’t add clear with sandpaper, so treat thin spots with care.
Polish And Protect
After 2000–3000 wet, move to a cutting compound on a foam pad. Work a small test area to confirm you’re removing the haze. Then refine with a finishing polish. Wipe with soft towels and inspect in sun or under LEDs. Top with wax or a coating once the surface is defect-free.
Quick Troubleshooting
Scratch Marks Keep Showing
You probably jumped grits. Go back one step, clear the pattern, then move up.
Panel Still Looks Wavy
The block is too short or too soft. Swap to a longer block and sand in long strokes with a guide coat.
Paper Loads Fast
There’s residue on the panel or you need dust extraction. Clean more often and try net abrasives for better airflow.
Burn-Through On An Edge
Stop. Mask the edge, spot base and clear, then blend as your system allows.
Supplies And Setup Checklist
- DA sander with dust extraction and assorted discs (80–400)
- Blocks: long, soft, and curve-friendly options
- Wet-sanding sheets: 600, 1000, 1500, 2000, 3000
- Guide coat, wax-and-grease remover, tack cloths
- High-build primer, sealer (per paint system)
- Compound, polish, foam pads, and clean towels
- Masking paper, plastic, fine-line tape
- Respirator, safety glasses, gloves, shop vacuum
Time And Materials Planning
Budget time by panel. A small bumper scuff needs an hour to sand, prime, and refine. A door with filler and primer can take half a day once you include cure windows. Fresh discs cut faster and save hours, so don’t stretch them. Keep two spray bottles on hand for wet work so the surface never dries. Track what you used per job in a simple log. Next time you’ll know how many sheets and pads to grab and how long the bay will be tied up. That keeps the work moving and helps you quote with confidence.
Method Notes And Constraints
Always match your grit path to the product sheet for your primer, base, and clear. Some systems want 600 wet before base; others want 800. Test a small area before you commit to a full panel. Work cool and clean. Heat, dust, and solvent traps are the enemies of flat paint.
Final Pass: Make It Paint-Ready
Wipe the panel with solvent and a tack cloth. Check every angle under strong light. If you see any leftover guide coat or shiny pits, keep sanding. When the surface shows a tight, even scratch across the whole repair, you’re ready to spray—or ready to polish, if you’re correcting clear only. This is the repeatable path for anyone asking how to sand car paint with confidence and control.