How to Sand Plaster Wall Repair to prep for repaint

Plaster Wall Repair sanding works best when you move up in measured steps. Use the progression below to prep for repaint while keeping scratches predictable and easy to refine.

Why Sanding Matters

On glass, ceramic, and stone surfaces, skipping grits often leaves a scratch pattern that becomes more visible after cleaning or polishing. A steady grit progression removes the previous grit’s scratches and makes the finish more uniform.

Tools

• Sanding block (for edges) or flat backing (for small flats)
• Spray bottle with water (wet sanding helps control dust and scratch consistency)
• Microfiber cloths
• Masking tape (protect adjacent surfaces)
• Raking light to check haze and leftover scratches

Recommended Grit Sequence

• 120 grit – Defect removal / first cut
• 150 grit – Remove the first grit’s scratches
• 180 grit – Refine for smoother finish
• 220 grit – Final refinement before polishing/sealing

Step-by-Step

1. Clean and protect. Remove residue and tape off nearby finished surfaces so you only work where needed.
2. Start with the first grit and keep pressure even. Use 120 Grit (25 Pack). Work until the defect is replaced by a uniform scratch pattern.
3. Use wet sanding to control heat and scratch consistency. A light mist of water helps reduce loading and keeps scratches more even.
4. Move up and erase the previous scratches. Use 150 Grit (25 Pack) and don’t advance until deeper lines are gone under raking light.
5. Finish with the final grit for your goal. Use 180 Grit (25 Pack) to refine the surface for polishing or sealing.
6. Final rinse and wipe. Remove slurry and let the surface dry so you can judge the true finish.

Special Cases

Edge shape: Use a backing block behind the paper so you don’t round edges unintentionally.

Small chips: Feather outward so the repair blends. Don’t stay in one spot too long or you’ll create a flat.

Pro Tips

• Use raking light often. It reveals haze and leftover scratches immediately.
• Don’t skip steps. Skipping grits often leaves scratches that reappear after cleaning.
• Keep it wet (when appropriate). Wet sanding reduces dust and helps keep scratches consistent.
• Change sheets early. Fresh abrasive cuts cleaner and reduces random scratches.

Aftercare

• Rinse away slurry completely and let the surface dry.
• If polishing, proceed only after the scratch pattern is uniform.
• For higher gloss, continue to higher grits and then polish.
• Store sheets flat and dry to prevent curling.

FAQs

• Wet or dry sanding? Wet sanding is often preferred on hard surfaces to control dust and improve scratch consistency.
• Why do I still see haze? Usually leftover scratches from a lower grit. Step back one grit, remove them fully, then continue.
• Can I stop at the recommended final grit? Yes for prep. For a higher gloss, continue to higher grits and polish.
• How do I avoid visible sanding marks? Don’t skip steps and confirm each grit has fully removed the previous scratches.

Watch & Learn

To repeat the same step-by-step refinement you just watched, keep these grits ready and move up in order: 120 Grit (25 Pack), 150 Grit (25 Pack), 180 Grit (25 Pack).

Once the surface looks uniform under good light, polishing or sealing becomes much more predictable. The main time-saver is simply not skipping grit steps.