Sanding Progression: Grits, Pressure, and When to Stop

Sanding is mostly about removing the scratches from the previous grit — not about pressing harder. A simple progression, checked under a raking light, beats a long session with one disc.

For a shorter overview that also covers first finishes, see sanding and finishing basics.

A practical grit ladder

Start with the finest grit that still removes the marks you have, then step up:

Jumping from 80 to 180 leaves deep scratches that disappear until finish hits them — then they telegraph as dark lines.

Random-orbit sander habits

• Light pressure. Let the pad cut; leaning on it makes swirl marks and clogs the disc.
• Keep it flat. Tipping rounds arrises and digs edges.
• Move slowly and overlap each pass by about half the pad.
• Change discs when cutting slows. A loaded disc burnishes instead of cutting.
• Hook up dust collection or a shop vac if your sander supports it; clear dust sanding cuts better and shows scratches sooner.

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The pencil trick

Scribble a light pencil grid across the surface before each grit. Sand until the grid is gone everywhere — edges and middle. Then wipe off the dust and move to the next grit. If pencil remains in a hollow, that grit isn’t done.

Hand-sand with the grain for the last pass

After the final machine grit, take a sanding block and a fresh sheet of that same grit (or one step finer) and sand with the grain. That cleans up the tiny arcs a random-orbit pad leaves. On moldings and inside corners, fold paper or use a foam pad so you don’t round crisp profiles unless you mean to.

Where to stop before stain vs. clear finish

• Pigment stain: many makers suggest stopping around 150–180. Sanding much finer can close the surface so pigment takes lighter and blotchier. Always test on a scrap sanded the same way as the project.
• Dye stain: often tolerates a finer surface; follow the product label and your sample board.
• Clear film finish: 180 is a solid default; 220 is fine if you want a smoother touch.
• Oil / oil-varnish blends: many woodworkers stop at 180–220, then raise the grain with a damp cloth, dry, and scuff before the first coat.

Between coats

After the first coat of finish is dry, scuff with 320 (or a fine abrasive pad) just enough to knock down dust nibs — you’re not sanding back to bare wood. Remove dust before the next coat. Details vary by finish; finishing schedules walks through full recipes.

Check before you finish

• Raking light: flashlight low across the surface shows swirls and glue.
• Mineral spirits wipe (ventilated area): temporarily previews the finished color and reveals glue spots and missed scratches. Let it evaporate fully before staining or finishing.
• Find and remove dried glue; it blocks stain and looks pale under clear coats.

Common mistakes

• Skipping grits after a coarse start.
• Bearing down on the ROS.
• Staining without a same-wood, same-grit sample.
• Leaving dust in pores — vacuum and wipe before finish.

Sources & further reading

• Fine Woodworking — All about sandpaper
• Your stain and finish labels for recommended final grit and recoat times