Concrete Patch: Grit Sequence for A Smoother Surface For Coating

If you’re sanding concrete patch for a smoother surface for coating, the fastest way to get a predictable result is to use a short grit progression and keep the abrasive cutting cleanly (not loading up). This guide focuses on concrete patch to reach a smoother surface for coating with consistent scratches, less rework, and fewer surprise marks after coating.

Why Proper Sanding Matters

concrete patch often has mixed hardness (filler, coating, base material), so pressure and grit choice matter. Start coarse enough to level defects efficiently, then step up in grits so each stage removes the previous scratch pattern. This keeps the surface uniform, improves adhesion, and makes the final finish look smoother under angled light.

Tools/Recommended Tools

• Sanding block (flat) for even pressure on flat areas.
• Flexible hand pad for edges, profiles, and light contouring.
• Vacuum/brush to clear dust between passes and reduce clogging.
• Angled work light to reveal scratches, ridges, and low spots.
• Microfiber cloth (dry) for a final wipe before coating.

Recommended Grit Sequence

• 150 grit — Cut/Level: Remove high spots, runs, heavy defects.
• 220 grit — Refine: Erase coarse scratches and even out the surface.
• 320 grit — Finish: Reduce visible scratches before coating.

Step-by-Step

1. Prep the area. Clean off dust, oils, or residue so the paper cuts instead of skating and loading.
2. Set a light at a low angle. Mark ridges, chips, or transitions so you sand only what matters.
3. Level defects with the first grit. Use light pressure and overlapping strokes with 150 Grit (25). Stop as soon as the surface is flat—don’t keep sanding once the defect is gone.
4. Refine the scratch pattern. Switch to 220 Grit (25) and sand until the previous grit’s lines are no longer visible under the light. Clean the surface between grits.
5. Finish for coating. Use 320 Grit (25) with very light pressure to unify the surface. This reduces the chance of scratches showing through paint, clear coat, or polish.
6. Remove dust completely. Vacuum and wipe with a dry microfiber. Leftover dust can create bumps and adhesion problems.
7. Coat and re-check. After primer/finish cures, inspect under angled light. If needed, do a quick touch-up with the final grit and re-coat.

Special Cases

Edges and corners: Reduce pressure and use a flexible pad to avoid rounding. Deep gouges: Fill or repair first—sanding alone can’t remove a low spot without flattening the whole surrounding area.

Pro Tips

• Use light pressure. Pressing hard creates random deep scratches and clogs paper faster.
• Don’t skip big jumps. Smaller grit steps remove scratches faster and save time overall.
• Clean between grits. A single coarse particle can carve lines during finishing passes.
• Swap sheets early. If cutting slows, change paper before you start pushing harder.

Aftercare

• Wipe down before coating. Dust is the #1 cause of gritty finishes and bumps.
• Between coats: A very light final-grit scuff can improve bond and remove dust nibs.
• Store sheets flat and dry. Flat paper cuts more consistently and lasts longer.

FAQs

• When do I move to the next grit? When the previous scratch pattern is gone under angled light.
• Why do I get swirl marks? Usually too much pressure, clogged paper, or skipping a grit step.
• Wet or dry? These sheets support wet or dry use—wet sanding can reduce airborne dust and help keep the surface cleaner.
• What grit should I stop at? For this workflow, stopping at 320 grit is a solid baseline before coating.

Watch & Learn

Need more grits for your next project? Browse this collection: Medium Grit.