Sandblasting is a method for engraving such materials as glass and granite or for cleaning metal and some buildings. Compressed air forces sand through a hose from the blasting machine. The sand acts as an abrasive to wear away scale on metal, dirt on stone buildings, or to smooth the surface of glass. Machines that have a rapidly rotating bladed wheel to hurl metal abrasives, particularly steel shot, are also used. Manufacturers prefer this method because it is faster and costs less.
