Sandpaper is a strong paper coated with abrasive pieces (silicon carbide, aluminum oxide or garnet) and is rated by the size of its grit. Smaller numbers indicate a coarser grit and higher numbers a finer. The silicon carbide, also known as wet/dry, is commonly used on stone, non-ferrous metals and plastics as it is the most durable and aggressive. Aluminum Oxide is for wood. And the garnet is an all purpose abrasive.
