---
title: "Which sandpaper grit for a final finish?"
description: "400 to 600 dry, or 800 to 2000 wet on a fully cured film, followed by a polishing compound. The ranked options, the technique that changes the outcome, and what goes"
url: https://atoneplace.net/which/sandpaper-final-finish/
site: "At One Place"
---

# Which sandpaper grit for a final finish?

**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.**

Rubbing out a finish is levelling rather than smoothing. The film has to be thick enough that you can cut its high points down to the level of its low points without breaking through, and cured enough that it powders under the abrasive rather than gumming — which for an oil-based varnish can mean two to four weeks, not the overnight recoat time. Silicon carbide is the abrasive of choice for wet work because its grains are sharp and friable, exposing fresh edges as they break, and because it is waterproof. Water with a drop of detergent floats the swarf away and stops the paper loading, and a rigid backing block is what makes the surface flat rather than wavy.

## The options, ranked

*Ranked best-first for the stated job. The third column is why the others exist.*

| Option | Good at | Bad at |
| --- | --- | --- |
| 400-600 grit | Flattens the last coat and removes dust nibs, leaving a satin surface ready for wax or polish. | Still leaves visible scratch pattern under a high gloss. |
| 800-2000 wet with silicon carbide | Levels the film properly, which is the only route to a true mirror finish on lacquer or clearcoat. | Requires a thick enough film to cut into, and a fully cured one. |
| Polishing compound | Removes the remaining fine scratches and brings up gloss; it is an abrasive too, just a very fine one. | Heats the surface if machine-applied too aggressively and can burn through an edge in seconds. |
| Wax or oil finish | A softer sheen that hides minor defects and is easily repaired. | Not a substitute for flattening; it will simply follow every ripple underneath. |

## Technique that changes the outcome

1. Let the film cure fully — days for water-based, weeks for oil-based varnish
2. Wet sand with silicon carbide paper, water and a drop of washing-up liquid
3. Use a flat block; fingers follow the ripples instead of removing them
4. Work up through the grits and wipe clean between them so a coarse grain does not scar the next stage
5. Finish with a fine polishing compound and a soft cloth or a slow machine

## What goes wrong

- Cutting into a thin film, which goes through to bare wood at an edge in one stroke
- Working dry, which loads the paper and heats the finish
- Polishing a finish that has not cured — it will haze and shrink later

> Compiled practical guidance rather than a published standard. Product formulations vary by brand and market, so read the label — and where the work is structural, electrical or gas, the regulations that apply where you are govern rather than anything here.

## Other sandpaper grit questions

| For | Use |
| --- | --- |
| Bare wood | 80 to 120 to 150 on softwood, finishing at 180 or 220 on hardwood — and stop there, because over-sanding ruins stain. |
| Stripping paint | 40 to 80 grit open-coat aluminium oxide or ceramic — but test for lead paint before sanding anything painted before the 1990s. |
| 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. |
| Between coats | 220 to 320 grit with almost no pressure — you are knocking off dust nibs, not removing the coat. |
| Plasterboard filler | 120 to 150 grit to level joint compound and 220 for the final pass, ideally on a mesh with a vacuum attached. |
| Plastic | Start at 320-600 wet for scratches, work up to 2000, then finish with a plastic polish — and keep it cool. |
| Car body filler | 80 grit to shape, 180 to refine, 320 before primer and 400-600 on the primer before paint. |
| Wet sanding | Silicon carbide wet-or-dry paper, water with a drop of detergent, a rigid block, and 800 grit upwards. |

## Common questions

### 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.

### What should I avoid?

Cutting into a thin film, which goes through to bare wood at an edge in one stroke Working dry, which loads the paper and heats the finish Polishing a finish that has not cured — it will haze and shrink later

## Related pages

- [Which sandpaper grit for bare wood before finishing?](https://atoneplace.net/which/sandpaper-bare-wood/)
- [Which sandpaper grit removes paint?](https://atoneplace.net/which/sandpaper-stripping-paint/)
- [Which sandpaper grit removes rust?](https://atoneplace.net/which/sandpaper-metal-rust/)
- [Which sandpaper grit between coats of paint or varnish?](https://atoneplace.net/which/sandpaper-between-coats/)
- [Which sandpaper grit for plasterboard and filler?](https://atoneplace.net/which/sandpaper-drywall/)
- [Which sandpaper grit for plastic?](https://atoneplace.net/which/sandpaper-plastic/)
- [Which sandpaper grit for car body filler?](https://atoneplace.net/which/sandpaper-body-filler/)
- [Which sandpaper should I use for wet sanding?](https://atoneplace.net/which/sandpaper-wet-sanding/)

## Sources

- Typical range compiled from manufacturer specifications — At One Place (/about/)