Whenever I was sanding by hand, the sandpaper would roll or slide in my hands, eventually tearing and turning into small, useless scraps. I tried folding it every which way until I finally solved the problem with a little spray adhesive. Now I cut a sheet of sandpaper in half and spray on a light coat of adhesive. Then, I fold the sandpaper to a quarter-sheet size, which is just right for hand-sanding. The glued paper doesn’t roll or slide and its double thickness makes it stronger.