Sanding does one job well and is easy to overthink: it replaces coarse scratches with finer ones until the remaining scratches are too small to see under finish. The mistakes that show up later, blotchy stain or visible swirl marks, almost always trace back to skipping a grit or stopping too soon at the coarse end. This note lays out a sequence that works for most furniture-grade solid wood.
The progression
Move up through grits without skipping more than one step. Each grit only needs to erase the scratches left by the previous one, so jumping too far means the next grit cannot keep up.
| Grit | Purpose |
|---|---|
| 80 | Only for heavy stock removal or removing old finish; many boards start finer |
| 120 | Remove planer and machine marks, level the surface |
| 150 | Erase the 120 scratches and even the surface |
| 180 | Refine before finishing; a sensible stopping point for many oil finishes |
| 220 | Final pass for film finishes or where a very smooth feel is wanted |
Sanding much beyond 220 on bare furniture wood can burnish the surface so finish and stain absorb unevenly. For most pieces, stopping at 180 to 220 is plenty.
Always with the grain
Hand sanding should follow the direction of the grain. Cross-grain scratches catch the light and become obvious the moment a finish goes on. With a random-orbit sander the marks are less directional, but a final pass by hand along the grain at your last grit cleans up the faint swirl the machine leaves behind.
Raising the grain
If you plan to use a water-based stain or finish, the water will swell the cut wood fibres and leave the surface feeling rough after the first coat. You can get ahead of this:
- Sand to your final grit, for example 180.
- Wipe the surface lightly with a damp, not wet, cloth and let it dry fully.
- Knock back the raised fibres with the same final grit, sanding gently.
The wetted birch surface in the photograph above shows why this step matters: water reveals both the raised fibres and any leftover scratches that were invisible on the dry board.
Checking your work
Inspect under raking light. Hold a lamp low and almost parallel to the surface, then look across it. Scratches and dips that vanish under overhead light stand out sharply this way. Wiping the surface with mineral spirits, where ventilation allows, also previews how the wood will look under finish and exposes any swirl you missed.
Common problems
- Swirl marks: a grit was skipped, or the machine was lifted while still spinning. Step back one grit and rework.
- Rounded edges and details: too much pressure on corners; let the abrasive do the work and ease pressure near edges.
- Clogged paper leaving streaks: change worn abrasive sooner, especially on resinous softwoods.
Dust matters
Wood dust is a respiratory irritant and some species are sensitizing. Work with dust collection or a vacuum at the sander, ventilate the shop, and wear a fitted respirator rated for fine particles. This is doubly relevant in a small, closed Canadian basement shop during winter when windows stay shut.
For finish-specific drying and recoat guidance, follow the instructions printed on your product, since they vary by brand and by the temperature and humidity of your shop.