Whether we like woodworking or not, most of us know something about sandpaper, even if it’s just the name. Sandpaper is really just a very smooth form of a chisel, for example, or any tool that reduces or alters wood. Sandpaper is made of small thick sheets. It goes without saying that they are very brittle and therefore wear out quickly.
One of the problems with using sandpaper is knowing which one to use for which job. To get started, you need to determine if you want commercial or industrial sandpaper. You’ll have less of a store hunt to buy it if you’re using the commercial grade, since most hardware or home building centers have it in stock. The industrial is more specialized and is an element that is used more frequently in the manufacturing line.
When you hear someone refer to sandpaper, chances are you hear them refer to sand. All this is, is the way to identify what force it is. You mean each of those little blades we talked about by the inch. So the lower the number, the coarser the sandpaper.
Now, with a little understanding, you need to determine which grain you need for which job. As we said, there are several to choose from and it will depend on the work you have to do. If you have heavy sanding where you need to remove paint or roughen the surface, you will need a coarse 40-60 grit. Lighter sanding is required to remove small blemishes, which means I’d use a medium 80-120 grit. Final sanding before finishing dictates the use of 150-180 fines. Then, in between the coat of stain, use the very fine one, which is 220-240. If you have some dust marks between these coatings you can use the 280-320 extra fine grit and finally for some light scratches you can use the 360-600 super fine grit.
Various backings are used on sandpapers, such as low-quality cloth or Kraft paper. These are maintained with bonding agents.
Going through the grits means working your project from the heaviest to the lightest sandpapers. Typically, if everything looks good, you can end up with 150-180 grit, though up to 200 if you’re going to be water-based.
You may hear a reference to open and closed layer sandpaper. The open layer has spaces between the grains, which means fewer clogs and is more applicable for woodworking. Closed grain works best on metal and wood finishes, but clogs easily.
There are four different types of sandpaper, each with a specific use. Aluminum oxide is the most used by carpenters. Garnet is also another favorite, but it is short-lived. Then silicon carbon plus for steel, paint, plastic and fiberglass and finally ceramic which is the most resistant of all. It is very expensive and is used exclusively for shaping and leveling.
You now have some basic knowledge about what types of sandpaper there are and their best uses.