Sandpaper or Glasspaper are a type of coated abrasive that consists of sheets of paper or cloth with abrasive material affixed to one face. Nowadays, sand or glass is not used.
Sandpaper is produced in different sizes and is used to remove unwanted material from surfaces, either to make them smoother (in painting and wood finishing), to remove a layer of material (e.g. old paint), or to make surface rougher (in gluing).
Types
Backing: Backing for sandpaper can have clothes (cotton, polyester, and rayon), PET film, and "fibre", or rubber apart from the paper.
Material: Garnet, emery, aluminium oxide, silicon carbide, alumina-zirconia, Chromium(III) oxide, ceramic aluminium oxide can also be used in sandpapers.
Bonds: Different adhesives, such as Hide glue, are used to bond the abrasive to the paper. Waterproof sandpapers use resin bond and a waterproof backing.
Open coat sandpapers have particles that are separated from each other and it is more flexible.