Level Wood Filler Patches: 120?180 Grit Before Topcoat

Wood filler makes repairs seamless—if it’s sanded right. Too coarse, and you’ll dish the patch; too fine, and you’ll polish it slick so the topcoat won’t blend. The sweet spot is a quick 120 ? 180 grit sequence. This guide shows you how to flatten patches flush, refine them for stain or paint, and avoid the halos that ruin otherwise perfect finishes.

Why Sanding Filler Matters

Wood filler dries harder than the surrounding wood. If you only sand with coarse paper, you’ll remove more of the soft wood and leave the filler proud. Sanding too fine burnishes the filler, creating shiny spots that resist stain. The balance is to level at 120, then refine at 180 for a surface that finishes evenly with the rest of the project.

Tools & Materials

• 9×11 in sandpaper sheets: 120 and 180 grit
• Hard sanding block for flats; small blocks or dowels for tight spots
• Random-orbit sander (optional) for large flat panels
• Pencil for guide-coat, raking light for inspection
• Vacuum and tack cloths

Recommended Grit Sequence

• 120 grit — Levels filler flush with surrounding wood.
• 180 grit — Refines scratches, sets up for stain or paint.

Step-by-Step: Smooth, Blended Patches

1. Overfill slightly. Apply filler proud of the surface. As it dries, it shrinks; overfilling ensures you don’t end up with a divot.
2. Map with pencil. Lightly pencil the patch and surrounding area. This guide shows when you’ve hit everything uniformly.
3. Level at 120 grit. With 120 grit (25-pack) on a hard block, sand the patch flush with the surface. Keep pressure even—avoid rocking, which can hollow soft wood around the patch.
4. Blend edges. Feather the edges lightly so the transition from filler to wood is invisible under finish.
5. Refine at 180 grit. Step to 180 grit (50-pack) and make a quick, even pass to erase 120 scratches. Don’t oversand—just unify the sheen.
6. Clean thoroughly. Vacuum and tack the area. Dust left behind mixes with finish and creates halos.
7. Finish coat. Apply stain or paint. The patch should now blend seamlessly with surrounding wood.

Special Cases

Stain-grade projects: Test filler color on a scrap first; some fillers absorb differently. Always stop at 180—higher grits can polish filler and cause mismatch.
Paint-grade projects: You can sand to 220 if needed, but 180 is usually plenty before primer.
Large patches: Spot-sand flush with 120, then blend wide with 180 so the repair doesn’t show as a flat “plateau.”

Pro Tips

• Always use a block—fingers dig trenches in soft wood.
• Let filler dry completely before sanding, or it will gum and tear.
• Replace paper early—dull paper polishes filler instead of cutting it.
• For deep gouges, build filler in layers; each layer sands flatter and bonds stronger.
• Use raking light to check for shadows or high spots before finishing.

Aftercare

• Inspect filled areas after the first coat; touch up with a light 180 scuff if needed.
• Store filler sealed tight—air-dried filler loses bond strength.
• For painted surfaces, spot prime patched areas to ensure even sheen.

FAQs

• Can I start with 80 grit? Too coarse—it cuts the wood around the filler faster than the filler itself.
• Why not stop at 220? On stain-grade projects, 220 can polish filler slick and cause blotches. 180 leaves the right scratch profile.
• Do I need a power sander? Not for small patches. A block gives more control and prevents hollowing.
• What if the patch looks shiny after sanding? You may have burnished it—reapply filler lightly, then sand again with fresh 120 ? 180.

Video: Leveling Filler Flush

Closing: For invisible patches, the recipe is simple: overfill, level at 120, refine at 180. Keep strokes flat, avoid over-sanding, and clean thoroughly before topcoat. Done right, the repair disappears under paint or stain.