How do I use sandpaper grades correctly?
Lower numbers remove material, higher numbers refine it — and why skipping grades leaves marks you only see after painting.
- Difficulty
- beginner
- Time
- 10 min
- Read
- 2 min
- Safety
- caution
Short answer
Start coarse enough to remove what you need, then work up through the grades without skipping more than one step. Each grade removes the scratches left by the previous one, which is the whole point of the sequence.
Sandpaper grades are a sequence rather than a set of options. The scratches from a coarse grade are invisible on bare wood and glaringly obvious under paint or varnish, which is why jumping straight to a fine grade fails.
Safety
Step by step
- Understand what the numbers mean.The grit number is the particle size — lower is coarser. 40-60 removes material fast. 80-120 is general preparation. 150-180 is smoothing. 220 and above is finishing and between coats.
- Start only as coarse as you need.Coarse paper removes material quickly and leaves deep scratches that take several grades to remove. Starting too coarse creates more work, not less.
- Work up through the grades.Do not jump from 60 to 220. Each grade removes the previous one's scratches; skipping more than one step leaves marks that show under a finish.
- Sand with the grain on wood.Across the grain leaves scratches that no amount of finer paper removes, and they appear the moment stain or varnish goes on.
- Remove the dust between grades.A vacuum then a damp cloth or tack cloth. Grit left on the surface from the previous grade keeps scratching while you use the finer one.
- Use a block or a sander for flat surfaces.Fingers alone follow the surface's existing bumps and round over edges. A block keeps it flat.
- Use 220 or finer between coats of paint or varnish.A light key rather than removal. It knocks back the raised grain and dust, and is what makes the second coat feel smooth.
- Change the paper when it stops cutting.Worn paper burnishes rather than sands and takes far longer. It is the cheapest part of the job — change it often.
Tips
- For preparing painted woodwork to repaint, 120 then 180 is usually enough. Going finer than 240 on something to be painted achieves nothing.
- Wet-and-dry paper used wet cuts finer, produces no dust and is the right choice for old paint that might contain lead.
- Raise the grain deliberately before final sanding on bare wood — wipe it with a damp cloth, let it dry, then sand. The finish stays smooth afterwards.
Questions people ask
What sandpaper grit should I use?
40-60 to remove material, 80-120 for general preparation, 150-180 to smooth, 220 and up for finishing and between coats. Work up through them rather than jumping.
Can I skip grades?
One step at most. Each grade removes the previous one's scratches, and jumping leaves marks that are invisible on bare wood and obvious under a finish.