Sandblasting is the technique of using a special tool, called a sandblaster, to remove or etch surfaces with sand. For most professional sandblasting jobs, an air compressor blasts silica sand onto the metal or glass surface at high velocity. Do-it-yourself sandblasting uses a siphon sandblaster, which is less potent than an air compressor but very suitable for glass etching and small sandblasting jobs. Sandblasting glass is the method of etching or smoothing the glass surface with millions of tiny silica sand particles at a high speed.
Etched, decorative glass is beautiful and retains the designs better than painted glass. Craftsmen and hobbyists can obtain sandblasting kits at home improvement centers or rental stores. The kits contain a ceramic nozzle, rubber hose and a pick-up tube. The siphon system draws the sand from a bucket into the pick-up tube and hose, where the sand is blasted out when the nozzle's trigger is pulled. Sandblasting stencil kits also are available, allowing the do-it-yourselfer to quickly and easily create a lovely work of etched glass.
Sandblasting was invented in the 1850's by American Benjamin Chew Tilghman, who saw the technique as a method for cleaning boilers, sharpening files and engraving glass bottles. Different grades of sand produce varying effects. Fine silica sand blasted into glass produces delicate patterns. Larger silica grains are best suited for cleaning corroded metals and cleaning large swaths of surface areas. Each sandblasting method requires a mechanism — usually a compressor — to produce enough air pressure to expel sand at very high rate of speed and under intense pressure.
There are dangers in working with tiny, abrasive particles at very high pressures, so sandblasting glass can be hazardous unless safety precautions are observed. The pressure from the equipment and the resistant hardness of the glass surface pulverize the silica into a fine dust. The dust, when inhaled, can cause respiratory problems. Safety goggles, ear muffs and a respirator protect the user's sensitive eyes, ears and throat from the erosive sand particles. Thick leather gloves, boots, chaps and overalls protect the user's body from errant blasts.
Sandblasting glass is a learned technique. Stencils lend guidance, but managing the direction of the nozzle and the intensity of the spray requires some skill. Experienced sandblasters recommend that new users experiment by sandblasting glass on scraps before attempting the main project.