Sandblasting is, in a nutshell, blasting sand—specifically, propelling it with such force and speed that it can actually clean a surface, or leave marks on it (such as designs, words, or patterns).
However, the term has also been applied when materials other than sand are used. That’s because silicosis, a lung disease, has been associated with inhalation of sand. For safety purposes, people have replaced it with any small and uniform particle. Examples include walnut shell, coconut shell, powdered abrasives, steel grit, and copper slag. Safety laws have also mandated the use of protective gear and ventilation during sandblasting.
Sandblasting requires special equipment—it’s not possible to just position a fan in front of a funnel and throw the material against a surface. People need a tool and set up that consists of an abrasive, an air compresser, and a blaster nozzle. It is also necessary to invest in a collector that will catch excess dust, or a workstation to keep small objects in place while they are being etched or cleaned.
The sandblasting process was developed and patented in 1870. It was first used as a way of cleaning large surfaces, such as ship hulls or even the Golden Gate Bridge (imagine how long it would take to scrub those with soap and water!). Sandblasting was also used to prime a surface before it was painted. It prevented dirt or bubbles from being trapped in the paint layer, creating imperfections that would become more visible when other layers were applied. Sandblasting was also used as a sealant.
Sandblasting is also used by craftsmen, especially those working with glass. It is cheaper than hand-etching and less prone to flaws than laser-etching.