Knowing which sandpaper grit to use — and in what order — is one of the most practical skills in making. Skip a grit and you will spend twice as long removing scratches. Use the wrong grit for the job and you will either waste time or damage your work. This guide covers the standard progressions for every common material and application.
How grit numbers work
The grit number refers to the number of abrasive particles per square inch of the paper. Lower numbers mean coarser, more aggressive paper; higher numbers mean finer, smoother paper. The jump between grits is not linear — the difference between 80 and 120 is much more dramatic than between 1000 and 1200. This is why skipping grits at the coarse end (say, jumping from 80 to 240) leaves deep scratches that take forever to remove, while skipping at the fine end is less critical.
Grit progression for bare wood
For general woodworking (furniture, boxes, shelves), a standard progression is 120 → 180 → 220. This produces a surface smooth enough for most finishes. If you are applying an oil finish where the surface texture is more visible, extend to 320 or even 400. Going finer than 400 on bare wood before finishing is usually unnecessary — the first coat of finish raises the grain anyway.
For rough stock removal (shaping, removing saw marks, flattening glue-ups), start at 80 and progress to 120 before switching to your finishing grit sequence. For end grain, which always appears rougher than face or edge grain, go one or two grits finer than the rest of the piece.
Grit progression for guitar finishing
Guitar finishing demands the finest surfaces of any woodworking discipline. The progression for level-sanding a cured nitrocellulose or polyurethane finish is typically 800 → 1000 → 1500 → 2000, all with wet-and-dry paper used wet. After 2000 grit, switch to polishing compound — first a cutting compound to remove the 2000-grit haze, then a fine finishing compound for mirror gloss.
Between coats of lacquer, a light scuff with 320 or 400 grit is sufficient — you are just removing dust nibs and providing a key for the next coat, not levelling the surface.
Grit progression for plastics
Acrylic, Kirinite, celluloid and other plastics can be polished to an optical-quality finish if sanded through enough grits. A typical progression for polishing a cut or machined acrylic edge is 240 → 400 → 600 → 800 → 1000 → 1500 → 2000, then a fine plastic polish or buffing compound. For pen turning, micro-mesh pads extend the sequence through 3200 → 4000 → 6000 → 8000 → 12,000 for a glass-like finish.
Wet sanding vs dry sanding
Wet sanding (using water or a light oil as a lubricant) is used for fine grits on finished surfaces, plastics and metals. The lubricant prevents the paper from clogging, reduces scratching, and carries away the sanding residue. Always wet-sand with wet-and-dry (silicon carbide) paper — standard aluminium oxide paper disintegrates when wet.
Dry sanding is used for bare wood and for coarse-grit work. Use a dust mask and extraction when dry sanding — fine wood dust is a serious respiratory hazard, and certain species (oak, mahogany, exotic hardwoods) are particularly harmful.
Paper types
Aluminium oxide: The most common abrasive for woodworking. Durable, good cutting action, works on all woods. Available in sheets, rolls and discs.
Silicon carbide (wet-and-dry): Harder and sharper than aluminium oxide. Used for wet sanding finishes, sanding plastics, and for fine grits. The dark grey or black paper you see in automotive finishing.
Garnet: A natural abrasive that fractures to expose fresh cutting edges as it wears. Produces an exceptionally smooth surface on bare wood. Preferred by hand-tool woodworkers for final sanding.
Ceramic: The most aggressive and longest-lasting abrasive. Used on sanding belts for heavy stock removal. Expensive but outlasts aluminium oxide many times over.
Sanding tips
Always use a flat sanding block on flat surfaces — finger sanding creates hollows and rounded edges. Sand with the grain on the final grit — cross-grain scratches show clearly under any finish. Change paper frequently: dull paper requires more pressure, which creates heat and uneven surfaces. And always remove all sanding dust before applying any finish — a tack cloth or slightly damp microfibre cloth picks up dust that compressed air leaves behind.
