Acrylic Scratch Removal: Sand & Polish (600–3000 Grit Guide)

Acrylic (PMMA) and plexiglass scratch easily and turn cloudy, but the good news is most surface damage lives in the top microns and can be erased with a disciplined wet-sanding and polishing workflow. This guide shows you how to move from visible scuffs and haze to a crystal-clear finish using a tight grit sequence, plastic-safe technique, and simple shop tools.

Why Sanding Matters on Clear Plastics

All sanding is scratching—your job is to replace deep, random scratches with an orderly, progressively finer scratch field that disappears when light passes through. Clear plastics amplify mistakes: skip a grit and you’ll leave “ghost” lines; press too hard and you’ll gouge or generate heat that warps edges. A measured, wet approach with a sensible grit map restores optical clarity without risking distortion.

Tools You’ll Need

• 9×11 in silicon carbide sheets (wet/dry): 600, 800/1000, 1500, 2000, 3000. eQualle sheets support wet or dry use.
• Sanding block set: one firm cork/rubber for flats, one soft foam for curves and edges.
• Clean water in a spray bottle with a drop of dish soap (lubricant), plus a rinse bottle.
• Microfiber towels, paper shop towels, and masking tape for edge protection.
• Raking/inspection light (LED) and a black background to evaluate clarity.
• Plastic polish or finishing compound (Novus/PlastX-style) and soft applicator pad.
• Optional: drill/DA polisher with foam finishing pad for large panels (keep RPM low).

Recommended Grit Sequence

• 600 grit: Levels oxidation and blends moderate scratches without biting too deep.
• 1000–1500 grit: Refines the 600 lines and tightens the scratch field.
• 2000–3000 grit: Leaves a uniform haze that polishes to optical clarity quickly.

Tip: Start as fine as you can while still making progress. If 600 won’t move a defect in a reasonable time, step down to 400–500 for a few passes, then resume the sequence.

Step-by-Step: From Hazy to Crystal Clear

1. Clean and mask. Wash the panel with mild soap and water. Mask adjacent painted trim or soft seals. Put a dark sheet behind the plastic so you can see your scratch pattern clearly.
2. Set up for wet sanding. Mix water with a small drop of dish soap. Flood the surface and your sheet. Work on a padded, stable surface so the panel doesn’t flex under pressure.
3. Level at 600 grit, light pressure. Wrap the sheet around a firm block for flat areas; use a soft pad on curves. Sand in straight, overlapping strokes and change direction (↔ then ↕) to ensure even coverage. For a reliable starting point that keeps you safe, reach for 600 Grit (25-pack) — it removes oxidation quickly but stays controllable on plastics.
4. Rinse and read the haze. Wipe clean and inspect under raking light. A uniform, fine matte means you’ve erased the original defects. Shiny pits or lines are low spots—spot-sand them with 600 and recheck.
5. Refine at 1000–1500. Step to 1000, then 1500 with the same light pressure. Keep the panel and paper very wet to prevent loading. If you’re doing multiple windows or a fairing, stocking a bulk option like 1500 Grit (50-pack) ensures consistent scratch quality across pieces.
6. Finish-sand at 2000–3000. Make long, even passes until the surface has a silky, uniform haze with no coarser lines hiding underneath. For the last step, a large quantity like 3000 Grit (100-pack) is perfect for big panels and for keeping a fresh sheet on the pad—fresh paper cuts cleaner and cooler.
7. Polish to clarity. Apply plastic polish by hand with a soft pad using slow circles and light pressure, or use a DA at low speed. Work until the haze disappears and the panel turns transparent. Wipe clean and inspect from multiple angles.
8. Edge and hole care. Switch to a folded sheet and feather-light touch around screw holes and inside radii to avoid creating “soft edges.” Never let a power pad catch an edge—finish these areas by hand.
9. Final check. Backlight the panel and view against the dark background. If faint lines remain, jump back one grit (usually 1500 or 2000) just in the problem zone, then re-polish.
10. Protect. Apply a plastic sealant or UV protectant to slow future oxidation. For motorcycle windscreens or boat isinglass, periodic reapplication preserves clarity.

Special Cases & Adjustments

Deep gouges: Spot-level with 400–500 on a small block, stopping as soon as the bottom of the scratch disappears. Immediately move through 600 → 1000/1500 → 2000/3000 in that spot to keep the blend invisible.

Cast vs. extruded acrylic: Cast acrylic tends to scratch less and polishes faster; extruded is softer and heats quickly. Reduce pressure and add more water on extruded sheets to avoid warping.

Polycarbonate (Lexan): Much softer than acrylic and more heat-sensitive. Use extra lubrication, shorter strokes, and keep the finest possible starting grit. Expect more time in the 2000–3000 range before polish.

Coated lenses and windscreens: Many headlight lenses and aircraft canopies carry hard coatings. If the coating is failing (yellow, cracked), sanding will remove it—be prepared to recoat, or stop and consult the manufacturer.

CNC edges and saw marks: Vertical striations need a brief diagonal pass at 600 before switching to with-edge strokes; finish with 1500 → 3000 and a quick polish.

Pro Tips

• Pressure discipline: Let the grit do the work. Heavy pressure creates troughs you’ll chase for hours.
• Keep it cool: Heat is the enemy. Use plenty of water, refresh sheets often, and pause if the panel warms.
• One-direction finishing: End each grit with three light passes in one direction; it makes it easier to confirm you’ve fully erased the previous pattern.
• Fresh sheets cut cleaner: If the sheet starts to drag or squeal, it’s loaded—rinse or swap.
• Test first: Practice on a scrap or a corner. Different plastics respond differently to pressure and heat.

Aftercare

• Wash with a soft mitt and mild soap; avoid dry wiping dusty panels.
• Use a plastic-safe spray detailer and plush microfiber to prevent micro-marring.
• Apply UV protectant regularly on outdoor pieces (motorcycle screens, boat windows).
• Store portable panels with soft separators so they don’t rub in transit.

FAQs

• Can I start at 400? Only for deep damage. The coarser you start, the more work you’ll do refining the field.
• Do I need power tools? No. Hand sanding gives the best control. A DA can speed polishing on large flats if you keep speed low and pad cool.
• Why is it still cloudy after 3000? The uniform haze is expected—polish removes it. If you see isolated lines, revisit 1500–2000 just in those spots.
• Flame polishing? Risky. It can craze the surface, distort edges, and trap stresses. Mechanical polish is safer and more consistent.
• Headlights too? Yes, but many headlights have factory hardcoats; if you sand them off, apply a new UV-stable clear to prevent rapid re-yellowing.

Video: Watch the Process

Closing

Clarity comes from control: keep pressure light, grits in order, and lubrication plentiful. Move deliberately—600 → 1000/1500 → 2000/3000 → polish—and read the surface under a raking light. With a handful of silicon carbide sheets and good habits, scratched acrylic returns to a clear, glossy window in less time than you’d think.