How to Sand Wood Properly (Grits, Tools & Technique)
Sanding is the step that separates a project you're proud of from one you're embarrassed by. It's also the step most beginners do wrong — either skipping grits and wondering why the stain looks blotchy, or sanding forever because they started too fine. Get the process right and finishing becomes straightforward.
Sanding isn’t glamorous but it’s not complicated either. The rules are simple: work through the grits in order, always sand with the grain, and stop when the surface is actually ready — not just when you’re tired of sanding. Everything else is detail.
Grit numbers: what they mean
The number is the mesh size — how many abrasive particles fit per square inch. Lower number means coarser abrasive and deeper scratches; higher number means finer abrasive and shallower scratches. Each grit removes the scratches left by the previous one. Skip a grit and you’re asking a finer paper to erase scratches it wasn’t designed for, which means you sand longer and still get uneven results.
Grit progression guide
| Grit | Category | When to use it |
|---|---|---|
| 60–80 | Coarse | Removing mill marks, smoothing rough-sawn timber, taking off a lot of material fast |
| 100–120 | Medium-coarse | General stock prep, flattening glue joints, initial smoothing of dimensioned timber |
| 150 | Medium | Most beginner starting points for clean dimensioned lumber |
| 180 | Medium-fine | Smoothing before a clear finish or light stain |
| 220 | Fine | Final prep before finish, between coats on oil and varnish |
| 320–400 | Extra fine | Between coats of paint or lacquer for a glass-smooth build |
For most beginner projects built from dimensioned (already surfaced) timber, you won’t need to start below 120. If you’re working with rough-sawn or reclaimed wood, start at 60 or 80 and work up. If the timber came from the hardware store and it’s smooth to the touch already, starting at 150 is fine.
Hand sanding vs power sanding
Both have a place. The mistake is treating them as interchangeable for every task.
Random-orbit sander (power)
A random-orbit sander moves in a random elliptical pattern so it doesn’t leave circular swirl marks the way a standard orbital does. It’s fast and forgiving — the right tool for flattening surfaces, working through grits on large panels, and doing the bulk of the work.
Limitations: it can’t get into corners, it can round over sharp edges if you’re not careful, and it generates a lot of fine dust. Use a dust bag or connect to a vacuum.
Technique: keep the sander moving. Dwelling in one spot creates dips you can’t see until you apply a finish. Light, overlapping passes. Let the weight of the sander do the work — pressing harder just loads the abrasive and reduces its life.
Hand sanding
Hand sanding is slower but more controlled. Use it for:
- Corners and recesses the power sander can’t reach
- Final passes before finish (a few passes by hand at 180 or 220 removes any remaining swirl marks from the random-orbit)
- Detail work and profiles
- Between coats of finish (power sanding is too aggressive here)
Always use a sanding block. A block — even a scrap of wood or a rubber block — distributes pressure evenly across the paper. Bare fingers concentrate pressure at the fingertips and leave ripples you can’t see until the finish goes on.
Sand with the grain
This is the one rule that, if broken, ruins finish work. The scratches from cross-grain sanding catch stain and show up as dark lines running across the surface. Always move the paper in the direction of the wood grain, not across it.
On a random-orbit sander the random pattern handles this for you — the machine doesn’t track across the grain. On final hand sanding passes, be deliberate about direction.
Raising the grain
Water-based finishes (water-based poly, water-based stain, latex paint) raise the grain — the wood fibers absorb the water, swell slightly, and stand up. If you don’t account for this, you end up with a rough, fuzzy surface under your first coat.
The fix is simple: after your final sanding pass, wipe the surface with a damp cloth (not soaking — just damp), let it dry completely (30–60 minutes), then give it a very light pass with 220 grit by hand. The fibers that would have raised are pre-raised and then cut back. Your first coat goes on smooth.
You don’t need to do this for oil-based finishes, but it doesn’t hurt.
Between coats
Most film finishes (varnish, polyurethane, lacquer) benefit from a light sanding between coats to knock down dust nibs and give the next coat something to grip.
Use 220–320 grit by hand after each coat has fully dried (check the finish’s instructions — “dry to touch” and “recoat time” are different things). Light passes — you’re not trying to cut back to bare wood, just scuffing the surface. Wipe off the dust with a tack cloth before applying the next coat.
When to stop
This is the part nobody teaches explicitly. You stop when:
- The scratches from the previous grit are completely gone — you can’t see or feel them.
- The surface is uniform — no shiny spots (means low areas), no scuff patterns, no mill marks showing through.
- You’ve reached the grit appropriate for your finish. For a stained or clear-coated piece, 180–220 is typically the endpoint. For painted work, 150 is usually enough.
A useful test: wipe the surface with a damp cloth or mineral spirits and look at it in raking light (light at a low angle). This simulates what a finish will show you. Every ripple, scratch, and dip shows up. Fix what you see now — it won’t get better after the finish goes on.
Dust management
Sanding dust is fine and gets everywhere. For health reasons as much as workshop reasons, manage it from the first pass.
- Connect your random-orbit sander to a shop vac via the sanding pad’s dust port. Even a partial capture is better than nothing.
- Wear a dust mask rated for fine particles (P2 minimum). A surgical mask doesn’t cut it for sanding dust.
- Wipe down the surface with a tack cloth before applying any finish. Loose dust trapped under a film finish telegraphs through every coat.
A note on finishing
Knowing when to stop sanding only matters if you’ve got a clear plan for what the finish is. Stain and clear coat decisions change what grit you finish at and whether you need to raise the grain. Our guide to staining and finishing wood covers the finish side of the equation.
And when a project plan specifies the finish — telling you what prep the designer tested and what products they used — the guesswork disappears. Our review of plan libraries covers what a complete plan actually includes, finishing instructions and all.
