Making Sense of Sandpaper
Knowing how it works is the first step in choosing the right abrasive
Synopsis: As Strother Purdy of Fine Woodworking learned, you can’t go right buying cheap sandpaper, but it’s still easy to go wrong with the best sandpaper that’s available. The key to choosing the right sandpaper is knowing how different kinds of sandpaper work. In this article, he explains sandpaper’s components and how they contribute to the performance, determining how quickly it works, how long it lasts, and how smooth the result will be. Sandpaper is a cutting tool, on a small scale. He explains how it’s made, how to sand efficiently with different grits and in different directions. He tells how to choose from among the four abrasive minerals, and he shares points about grading scales. He talks about backings and bonds and why they are important. Separate side notes on each mineral type help clarify the differences, and the article includes an abrasive grading system chart.
Years ago at a garage sale, I bought a pile of no-name sandpaper for just pennies a sheet. I got it home. I sanded with it, but nothing came off the wood. Sanding harder, the grit came off the paper. It didn’t even burn very well in my wood stove. Sanding is necessary drudge work, improved only by spending less time doing it. As I learned, you can’t go right buying cheap stuff, but it’s still easy to go wrong with the best sandpaper that’s available. Not long ago, for example, I tried to take the finish off some maple flooring. Even though I was armed with premiumgrade, 50-grit aluminum-oxide belts, the work took far too long. It wasn’t that the belts were bad. I was simply using the wrong abrasive for the job. A 36-grit ceramic belt would have cut my sanding time substantially.