Sandpaper grit
9 materials and what works on each.
| For | Use | First alternative |
|---|---|---|
| Bare wood | 80 to 120 to 150 on softwood, finishing at 180 or 220 on hardwood — and stop there, because over-sanding ruins stain. | 120-150 grit |
| Stripping paint | 40 to 80 grit open-coat aluminium oxide or ceramic — but test for lead paint before sanding anything painted before the 1990s. | 80 grit |
| Rusty metal | 60 to 80 grit to strip scale, 120 to 180 to blend — then prime the same day, because bare steel flash rusts within hours. | 120-180 grit |
| Between coats | 220 to 320 grit with almost no pressure — you are knocking off dust nibs, not removing the coat. | Stearated (non-loading) paper |
| Plasterboard filler | 120 to 150 grit to level joint compound and 220 for the final pass, ideally on a mesh with a vacuum attached. | 220 grit |
| Plastic | Start at 320-600 wet for scratches, work up to 2000, then finish with a plastic polish — and keep it cool. | 800-2000 wet |
| Car body filler | 80 grit to shape, 180 to refine, 320 before primer and 400-600 on the primer before paint. | 180 grit |
| Final finish | 400 to 600 dry, or 800 to 2000 wet on a fully cured film, followed by a polishing compound. | 800-2000 wet with silicon carbide |
| Wet sanding | Silicon carbide wet-or-dry paper, water with a drop of detergent, a rigid block, and 800 grit upwards. | Aluminium oxide paper |
- Which sandpaper grit for bare wood before finishing? 80 to 120 to 150 on softwood, finishing at 180 or 220 on hardwood — and stop there, because over-sanding ruins stain.
- Which sandpaper grit removes paint? 40 to 80 grit open-coat aluminium oxide or ceramic — but test for lead paint before sanding anything painted before the 1990s.
- Which sandpaper grit removes rust? 60 to 80 grit to strip scale, 120 to 180 to blend — then prime the same day, because bare steel flash rusts within hours.
- Which sandpaper grit between coats of paint or varnish? 220 to 320 grit with almost no pressure — you are knocking off dust nibs, not removing the coat.
- Which sandpaper grit for plasterboard and filler? 120 to 150 grit to level joint compound and 220 for the final pass, ideally on a mesh with a vacuum attached.
- Which sandpaper grit for plastic? Start at 320-600 wet for scratches, work up to 2000, then finish with a plastic polish — and keep it cool.
- Which sandpaper grit for car body filler? 80 grit to shape, 180 to refine, 320 before primer and 400-600 on the primer before paint.
- Which sandpaper grit for a final finish? 400 to 600 dry, or 800 to 2000 wet on a fully cured film, followed by a polishing compound.
- Which sandpaper should I use for wet sanding? Silicon carbide wet-or-dry paper, water with a drop of detergent, a rigid block, and 800 grit upwards.