How to Sand Drywall Patch to Remove Ridges

If you’re working on drywall patch and want to remove ridges, the difference between a patchy result and an invisible finish is the grit sequence and pressure control. These silicon carbide sheets work for wet or dry use, so you can reduce dust when needed.

Why Sanding Matters

Sanding levels ridges, removes nibs, and creates a uniform scratch pattern so primer/paint (or clear coat) bonds evenly. Jumping to a fine grit too soon leaves high spots; staying too coarse too long leaves scratches that show through.

Tools

• Sanding block or hand pad (keeps pressure even)
• Dust mask/respirator and safety glasses
• Tack cloth or microfiber
• Vacuum or brush attachment for cleanup
• Optional: spray bottle for wet sanding

Recommended Grit Sequence

• 150 grit
• 220 grit
• 320 grit
• 400 grit

Step-by-Step

1. Clean and inspect. Remove dust/grease so you don’t grind contaminants into the surface.
2. Start leveling. Use 150 Grit (50) to knock down ridges and blend transitions with light, even strokes.
3. Refine the scratch pattern. Move to 220 Grit (50) and overlap your passes to erase the previous grit lines.
4. Finish for coating. Use 320 Grit (50) to get a smooth, uniform surface that’s ready for primer/paint (or the next finish step).
5. Check with angled light. Shine a light across the surface—high spots and scratches show immediately.
6. Final cleanup. Vacuum, then wipe with a clean cloth (slightly damp for wet sanding) before coating.

Special Cases

Edges and corners: Switch to a sanding block and reduce pressure—edges cut faster than flat fields.
Curves: Wrap the sheet around a flexible pad so the grit stays in full contact.
Between coats: Use the finest grit in your sequence and sand just enough to dull the sheen.

Pro Tips

• Don’t skip more than one grit step—each grit removes the scratches from the one before it.
• Let the abrasive do the work. Too much pressure creates swirls and uneven low spots.
• For wet sanding, keep the surface lightly lubricated and wipe slurry often to check progress.
• Replace sheets when they stop cutting; worn abrasive causes burnishing instead of smoothing.

Aftercare

• Remove all dust before coating—leftover grit can telegraph through paint or clear coat.
• Store sheets flat and dry so edges don’t curl.
• If you wet sanded, let the surface fully dry before primer/paint.

FAQs

• Can I use these sheets wet? Yes—silicon carbide sheets are designed for wet or dry use; wet sanding helps control dust and clogging.
• How do I know when to move up a grit? When the previous grit scratches are uniformly replaced by the new, finer pattern.
• Should I sand in circles? Usually no—use straight passes and change direction slightly with each grit for even coverage.

Watch & Learn

Tip: watch for how the scratch pattern changes as grit increases—when the surface looks uniform under angled light, you’re ready to move on.

If you want to match this exact sequence, start with 150 Grit (50) and work up through the next grits for a clean, even finish.