This 3M Aluminum Oxide Sandpaper is a general purpose abrasive that can be used on painted surfaces, bare wood, and metal. Sanding is an integral step in preparing a surface to receive a coating, so for the best sanding results, use this fine-grit sandpaper with the grain of the wood and work through a sequence of grits from coarse to very fine. The 9 in. x 11 in. 3M sandpaper sheets can be cut to size to use by hand, on a sanding block, or a power tool sander.