Sand Plaster Patches: 120?180?220 Grit

Plaster wall patches often stand out if not blended smoothly. The key to seamless repairs is sanding with 120 ? 180 ? 220 grit. This sequence removes ridges, feathers edges, and creates a paint-ready finish that hides the patch completely.

Why Sand Plaster Patches

Fresh plaster dries unevenly, leaving bumps and trowel marks. Without sanding, these show through paint. Progressive sanding ensures edges taper into surrounding wall, making the patch invisible after painting.

Tools & Materials

• 9×11 in sandpaper sheets: 120, 180, 220 grit
• Sanding block or pole sander
• Vacuum with HEPA filter
• Tack cloths or microfiber rags
• Primer and paint
• PPE: respirator, goggles, gloves

Recommended Grit Sequence

• 120 grit — Levels ridges and high spots.
• 180 grit — Refines surface, feathers edges.
• 220 grit — Final smoothing for paint-ready finish.

Step-by-Step: Sanding Patches

1. Inspect patch. Shine light at angle to reveal bumps.
2. Sand with 120 grit. Start with 120 grit (25-pack) to knock down rough spots.
3. Step to 180 grit. Switch to 180 grit (50-pack) for smoother blending.
4. Final sanding at 220 grit. With 220 grit (100-pack), achieve paint-ready surface.
5. Clean surface. Vacuum thoroughly and wipe with tack cloth.
6. Prime & paint. Apply primer to seal patch, then paint entire area.

Special Cases

Large patches: Feather sanding wider for seamless blending.
Thin skim coats: May need only 180 ? 220 grits.
Old walls: Watch for brittle plaster—sand lightly to avoid crumbling.

Pro Tips

• Sand with light pressure—plaster scratches easily.
• Alternate directions for even blending.
• Don’t oversand edges—avoid depressions around patch.
• Replace paper often—plaster clogs grit quickly.
• Always prime—paint alone doesn’t seal patch well.

Aftercare

• Inspect patches periodically—repair small cracks early.
• Touch up with 220 grit before repainting.
• Keep walls clean with gentle dusting.

FAQs

• Can I skip to 220 grit? Not recommended—120 removes ridges faster.
• Do I need primer? Yes—primer prevents patch from flashing under paint.
• What if patch crumbles? Apply more plaster and sand again.
• Can I wet sand? Yes—controls dust but slower drying.

Video: Sanding Wall Patches

Closing: With 120 ? 180 ? 220 grit sanding, plaster patches blend seamlessly into surrounding walls, leaving a smooth, paint-ready finish.