Sandblasting or bead blasting is a generic term for
the process of smoothing, shaping and cleaning a hard surface by
forcing solid particles across that surface at high speeds; the effect
is similar to that of using sandpaper, but is faster and provides a
more even finish with no problems at corners or crannies. Sandblasting
can occur naturally, usually as a result of particles blown by wind
causing aeolian erosion, or artificially, using compressed air.
Sandblasting equipment typically consists of a
chamber in which sand and air are mixed. The mixture travels through a
hand-held nozzle to direct the particles toward the surface or
workpiece. Nozzles come in a variety of shapes, sizes, and materials.
Tungsten carbide is the most popular nozzle liner material for mineral
abrasives. Silicon carbide and boron carbide are more wear resistant
and are for use with harder abrasives such as aluminum oxide.
Inexpensive abrasive blasting systems and smaller cabinets use a
Historically, the material used for artificial
sandblasting was sand that had been sieved to a uniform size. In the
early 1900s, it was initially assumed that
sharp-edged grains provided the best performance
though this was later demonstrated to not be correct.
Other materials for sandblasting have been
developed to be used instead of sand; for example, carborundum
grit,steel shot and grit, copper slag, powdered slag, glass beads (bead
blasting), metal pellets, dry ice, garnet, powdered abrasives of
various grades, and even ground coconut shells, corncobs, walnut
shells, and baking soda (sodablasting) have been used for specific
applications and can produce distinct surface finishes. Some commercial
grade blasters are specially designed to handle multiple blast
abrasives. These blasters are commonly referred as multi-media