What Grit Sandpaper to Use on Wood Filler?

Choosing the right grit sandpaper for wood filler depends on the filler’s cure stage, desired smoothness, and surrounding wood surface. The process typically involves two key grit ranges to balance efficiency and finish.

For initial sanding (once the filler is fully cured but still slightly raised), use 120–150 grit sandpaper. This medium grit efficiently trims excess filler without digging into the wood or leaving deep scratches. It works for both water-based and solvent-based fillers, leveling the surface to match the wood’s contour.

For final sanding, switch to 220–320 grit sandpaper. This fine grit smooths out any remaining marks from the initial sanding, creating a seamless blend between the filler and wood. It’s ideal for preparing the surface for staining, painting, or finishing—ensuring the filler area doesn’t stand out.

Avoid ultra-coarse grits (below 100) as they can damage the wood and leave irreversible scratches. For delicate woods or fine finishes, opt for 320 grit for the final pass. Always sand with the wood grain and use light pressure to prevent unevenness or filler dislodgment.