What Grit Sandpaper Should You Use to Prep for Paint?

Choosing the right sandpaper grit for paint prep depends on both the starting surface condition and which stage of the prep process you're at — using the right grit at each stage genuinely affects both efficiency and final finish quality.

1. Coarse grits (40-80) for heavy material removal

Coarse grits are appropriate for removing thick paint buildup, leveling significant surface irregularities, or stripping down to bare wood or metal — these grits work fast but leave a rough surface that needs further refinement before painting.

2. Medium grits (100-150) for general surface prep

Medium grits smooth out the rougher marks left by coarse grit sanding and handle general surface prep on wood, metal, or drywall that doesn't need heavy material removal — this is often the starting point for surfaces already in reasonably good condition.

3. Fine grits (180-220) for deglossing and final smoothing

Fine grits are the standard choice for deglossing an existing painted or varnished surface before repainting (following the deglossing principle covered throughout this site) and for final smoothing before primer or topcoat application on most surfaces.

4. Very fine grits (320+) for between-coat sanding

Very fine grits are used for light sanding between coats of paint or finish (as covered elsewhere on this site), knocking down raised grain and dust nibs without removing meaningful material or leaving visible scratches under the next coat.

5. Matching grit progression to the project

For a surface needing significant paint removal, working through a grit progression (coarse to remove bulk material, then progressively finer grits to smooth) gives a better final result than jumping straight to a fine grit, which would take far longer to remove the same material and wouldn't address deeper surface irregularities.

6. Matching grit to the specific material

Softer materials (like pine or MDF) generally need less aggressive grits to avoid over-sanding or damaging the surface, while harder materials (dense hardwoods, metal) can tolerate more aggressive coarse grits without the same risk of gouging — adjusting grit choice to material hardness avoids over- or under-sanding.

7. When in doubt, start with a finer grit and escalate if needed

For an unfamiliar surface or material, starting with a finer grit and only moving to something coarser if it proves inadequate is a safer approach than starting aggressive and risking unnecessary damage — it's easier to escalate to a coarser grit than to undo damage from starting too aggressively.