How to Sand Joint Compound to Fix Sanding Marks (No Swirl Marks)

Jordan Avery
2026-02-23T14:26:36-06:00

To get the best result on joint compound while aiming to fix sanding marks, keep your grit jumps small and your pressure consistent. These silicon carbide sheets are suitable for wet or dry use, so you can choose faster dry sanding or cleaner wet sanding depending on the stage.

Why Sanding Matters

A consistent scratch pattern is what makes a finish look even. Proper sanding removes bumps, blends repairs, and prevents coarse scratches from telegraphing through paint, clear coat, or topcoat.

Tools

Sanding block (flat surfaces)

Foam hand pad (curves and contours)

Vacuum/brush for dust

Microfiber cloth

Optional: spray bottle for wet sanding

Recommended Grit Sequence

150 grit

220 grit

320 grit

400 grit

Step-by-Step

1. Clean the surface. Remove dirt and residue so you don’t sand contaminants into the material.

2. Level imperfections. Use 150 Grit (25) to flatten ridges and blend transitions.

3. Refine the surface. Switch to 220 Grit (25) and sand until the scratch pattern looks uniform.

4. Final smoothing. Use 320 Grit (25) to prepare for coating, polishing, or the next finish step.

5. Inspect under angled light. Look for leftover deep lines or shiny low spots.

6. Wipe down thoroughly. Remove dust (and let the surface dry if wet sanded) before applying any finish.

Special Cases

Soft materials: Use lighter pressure and a block to avoid gouges.
Edges: Feather strokes and avoid lingering—edges sand faster.
Clogging: Switch to wet sanding, rinse the sheet, and wipe slurry often.

Pro Tips

Sand in straight, overlapping passes; avoid tight circles that can create swirls.

Change direction slightly with each grit to reveal leftover scratches.

Use fresh sheets for the final grit—worn abrasive can leave inconsistent marks.

Stop as soon as the surface is uniform; over-sanding can round details.

Aftercare

Vacuum dust first, then wipe with microfiber for a clean surface.

Store unused sheets flat to prevent curling and creasing.

If you wet sand, allow full drying time before primer/paint.

FAQs

Wet vs dry—what’s better? Wet sanding reduces dust and helps keep the abrasive from loading; dry sanding can cut faster on raw material.

How do I know I’m done with a grit? When the scratch pattern is consistent and the previous grit scratches are gone.

Do I need to use every grit listed? Use the sequence as a guide—don’t skip large jumps if you want an even finish.

Watch & Learn

Pay attention to how the surface is cleaned between grits—removing dust and slurry is key to avoiding random deep scratches.

For a repeatable finish, follow the sequence and keep pressure light—start with 150 Grit (25), then progress upward for a smoother result.