Hods Sandpaper Grits Explained: What the Numbers Mean
Sandpaper grit numbers indicate the coarseness of the abrasive particles. Lower numbers mean larger, more aggressive particles. Higher numbers mean smaller, finer particles. The difference between 80-grit and 220-grit determines whether you are removing material or polishing it, and using the wrong grit at the wrong stage wastes time, creates problems, and produces poor finishes. Here is what each grit range does and when to use it.
Sandpaper Grits Explained
How Grit Numbers Work
The grit number corresponds to the number of particles that fit through a one-inch square screen. An 80-grit screen has 80 openings per inch, so the particles are roughly 1/80 of an inch (0.0125 inches or about 0.18mm). A 220-grit screen has 220 openings per inch, producing particles about 0.068mm — less than half the size.
Larger particles cut deeper scratches and remove more material per pass. Smaller particles leave shallower scratches and a smoother surface. The goal of sanding is to progressively replace deep scratches with shallower ones until the surface is smooth enough for the intended finish.
Grit Ranges and Their Uses
40-60 Grit: Aggressive Material Removal
These are the roughest common grits. They remove material fast and leave deep scratches visible from across the room. Use only when significant stock removal is required:
- Stripping heavy paint and old finishes with a belt sander
- Rough shaping with a random orbit sander
- Flattening severely uneven surfaces
- Removing heavy rust from metal tools
Never start with 40 or 60-grit unless the surface demands it. Starting too coarse creates deep scratches that take significant time to sand out at higher grits.
80 Grit: Stock Removal and Flattening
The starting point for most projects that need surface correction. Levels glue-up joints, removes planer snipe, and flattens rough-sawn surfaces. The scratches from 80-grit are visible but manageable — they sand out readily at 120-grit.
Start here when: the surface has visible imperfections, machine marks, or unevenness that 120-grit cannot remove quickly.
100 Grit: Transition Grit
Bridges the gap between 80 and 120. Some woodworkers include it in their progression; many skip directly from 80 to 120. Including 100-grit makes each step lighter and faster, which matters on large surfaces. On small projects, skipping 100 saves a step without noticeable quality loss.
120 Grit: The Standard Starting Grit
For surfaces that are already reasonably flat and smooth — fresh from the planer, jointer, or table saw — start at 120-grit. This removes light machine marks and prepares the surface for finer sanding.
120-grit is the workhorse. It is coarse enough to correct minor imperfections and fine enough to leave a surface approaching finish-ready.
150 Grit: Pre-Stain Preparation
150-grit removes 120-grit scratches and begins producing a genuinely smooth surface. This is the minimum grit for applying finish directly (without stain).
For surfaces that will be stained, many woodworkers finish sanding at 150 to 180-grit. The slightly open surface at 150 allows stain to penetrate evenly. Going finer closes the pores and can cause uneven stain absorption.
180 Grit: Stain-Ready
The ideal stopping point for oil-based stain application. The surface feels smooth to the touch, and the microscopic scratches accept stain uniformly. Cross-grain scratches from previous grits are eliminated.
For paint-grade surfaces, 180-grit after primer provides adequate smoothness.
220 Grit: Finish-Ready
The standard stopping point for bare wood that will receive clear film finishes (polyurethane, lacquer, varnish). The surface is glass-smooth under normal touch. Under raking light, faint sanding marks may still be visible, but they disappear under the first coat of finish.
Do not sand beyond 220 before staining. Higher grits polish the wood and close the pores. Stain sits on the polished surface instead of penetrating, resulting in blotchy, uneven color. Save 220+ for between-coat sanding after the stain has been sealed.
320-400 Grit: Between-Coat Sanding
Used between coats of polyurethane, lacquer, or paint. The goal is to level dust nibs, orange peel, and minor imperfections in the finish layer without cutting through to the stain or bare wood.
Light pressure. The finish coat should be cured before sanding — test by sniffing (if you smell solvents, wait longer).
600-2000 Grit: Polishing and Rubbing Out
For rubbing out a final finish to a satin or high-gloss sheen. Wet-sand with 600, 800, 1000, 1500, and 2000-grit in sequence (with water or mineral oil as lubricant). Follow with rubbing compound and paste wax for a glass-like finish.
This level of sanding is for fine furniture, musical instruments, and high-end woodworking. Not needed for home projects, decks, or workshop fixtures.
Sandpaper Backing Materials
Paper-Backed
Standard sandpaper for hand sanding and orbital sander discs. Available in A-weight (thin, flexible, for fine grits and detail work) and C-weight (heavier, stiffer, for coarse grits and power sanding). Tears easily when wet. The cheapest option.
Cloth-Backed
Used for belt sanders and heavy-duty sanding. Stronger and more flexible than paper. Resists tearing and handles wet sanding. Costs more per unit but lasts significantly longer. Standard for sanding belts.
Film-Backed
Polyester film backing with precision-graded abrasive. Used for fine finishing work (320+ grit) where uniformity matters. 3M Microfinishing Film is the premium option. Produces the most consistent scratch pattern.
Abrasive Materials
Aluminum Oxide
The standard abrasive for wood sanding. Self-sharpening — the particles fracture during use, exposing fresh cutting edges. Works on bare wood, painted surfaces, and light metal sanding. Found on most sandpaper sold at hardware stores.
Silicon Carbide
Harder and sharper than aluminum oxide. Used for wet sanding finishes, sanding between coats, and sanding harder materials (glass, stone, metal). The standard abrasive on wet-dry sandpaper. Black or gray color.
Zirconia Alumina
Extremely durable abrasive used on heavy-duty sanding belts and discs. Self-sharpening. Lasts 3 to 5 times longer than aluminum oxide on hardwoods. Blue or purple color. Worth the premium for belt sander belts that see heavy use.
Ceramic Alumina
The premium abrasive. Used on Norton Blaze and 3M Cubitron discs. Self-sharpening with micro-fracture technology that maintains consistent sharpness throughout the disc life. Expensive but dramatically outlasts standard aluminum oxide in power sanding applications.
Quick Reference
| Grit | Abrasive Size | Use |
|---|---|---|
| 40-60 | Coarse | Heavy removal, paint stripping |
| 80 | Medium-coarse | Stock removal, flattening |
| 120 | Medium | Starting grit for flat surfaces |
| 150 | Medium-fine | Pre-stain preparation |
| 180 | Fine | Stain-ready surface |
| 220 | Very fine | Clear finish-ready surface |
| 320-400 | Extra fine | Between coats |
| 600+ | Ultra fine | Polishing, rubbing out |
Bottom Line
Use 80 to 120-grit for initial smoothing, 150 to 180 for stain preparation, and 220 for clear finish preparation. Sand between finish coats with 320 to 400. Do not skip more than one grit step. Buy quality random orbit sander discs (3M, Norton, Diablo) — they cut faster, last longer, and produce better surfaces than bargain discs. A box of 50 discs in each grit from 120 through 320 covers most sanding needs for a year.