Grit numbers range from 24 (extra-coarse) all the way up to over 1000—though most home improvement projects use sandpaper in ...

The higher the number, the finer the grit. Coarse grits progress from 24 to 30 to 36, while fine ones rise from 600 to 800 to 1,000 and beyond. Because coarse and fine sandpaper grits are used ...

Wet-sand the damaged areas "in a cross-hatch pattern," Haas says, starting with 220-grit sandpaper. Sand the areas again using 400, 600 then 800-grit sandpaper. Rinse the surface with water.