How To Choose Sandpaper

There are many varieties of sandpapers on the market, and some types work much better than others on do-it-yourself projects.

For the money, you’re probably going to get the most use out of aluminum oxide sandpaper. It’s light brown and has hard, uniform and long-lasting grains. This makes it excellent for power sanding.

Another all-purpose abrasive is garnet paper, which is a reddish color. During sanding, its grains fracture, continually exposing fresh, sharp cutting edges. These edges allow it to cut quickly and make it suitable for hand sanding. Garnet paper, however, wears quickly.

Silicon carbide sandpaper has the hardest grit—it’s hard enough to sand metal. Because it comes in very fine grit sizes, it’s ideal for sanding coats of varnish and other finishes. Silicon carbide papers are marketed as "wet-or-dry carbide paper." As the name implies, it works in wet or dry conditions, which can be helpful. By lubricating it with water or oil, you can keep the paper from gumming up.

Another fast-cutting paper is stearate paper. This is a carbide or aluminum oxide paper that has been coated with a light gray or white compound. This coating keeps it from getting clogged with dust, making it effective on soft wood, which can gum other papers.

Unless you select the proper grit size, none of these sandpapers will give you the results you want. Remember that as the numbers get larger, the grains get smaller. And smaller grains provide finer sanding. For example, 60 or 80 grit papers should be used for coarse removal of materials.

For smoothing, start with 100 or 120-grit paper. As you sand, switch to progressively higher numbered paper until the finish is smooth. This means you’ll need to use grits in order, without skipping steps.

Your first sanding should flatten the high spots. As you switch to finer grains, the scratches made by the coarser paper will become smaller and eventually will disappear. For pine wood, you can stop at 120. But for oiled maple, you’ll probably want to polish it with 400 wet-or-dry paper.

Before you stain or varnish, sand the wood to about 200 grit paper. If you’re going to paint the wood, sand it to 150 grit.