Sand blasting is a general term used to describe the act of propelling very fine bits of material at high-velocity to clean or etch a surface.
Sandblasting is the colloquial term for abrasive blasting, which was patented way back in October 18, 1870 by the American soldier and inventor, Benjamin Chew Tilghman. According to apocrypha, he was inspired by seeing the wind blow the sands of the desert while he served as a general in the army. He then created the sandblasting process, highlighting its possible use in engraving bottles, cleaning boilers and sharpening files. He was awarded a similar patent in the UK during the following year.
Modern sandblasting has not differed much from the principle Tilghman created over a century ago. A stream forcibly propels abrasive material under high pressure, and this constant and repetitive abrasion eventually smooths out a rough surface, roughens a smooth surface, shapes a surface or cleans it, depending on the manner in which it is used.
There are a lot of variants on sandblasting. Despite its name, sandblasting may involve a lot of different materials. Compressed air and water are usually employed as the propellants for the abrasive material.