Sandblasting is one of the abrasive blasting surface preparation techniques that include bead, dry ice, and shot blasting. The process involves directing a stream of specially-graded sand suspended in a jet of high-pressure gas or liquid at a surface, the abrasive impact of the sand particles removing rust, scale, and contaminants in the process. There are several broad categories into which sandblasting machinery falls, namely portable systems, blast cabinets, and blast rooms. All of these systems function in a similar fashion and differ only in size, complexity, and the applications for which they are used. Components common to all of the systems are a propellant source, a blast pot containing the sand, and a set of hoses and appropriate nozzles.
Abrasive blasting is a surface preparation method that employs a high-energy stream of propellant to blast an abrasive material onto a surface to strip, clean, and roughen it in readiness for painting or other finishes and treatments. A wide variety of abrasive materials are used in these systems including sand, steel shot, and even crushed nut and fruit kernel shells. Propellants are typically high-pressure compressed air or water or, in the case of a wheel blasting, centrifugal force generated by a rapidly rotating wheel. Sandblasting machinery generally falls into one of three basic categories based on the size, portability, and intended end use of the equipment, although all work according to common principles. These are portable equipment, blast cabinets, and blast rooms.
Portable sandblasting machinery are the smallest of the three types and may be moved by hand, on a trailer, or pickup bed. They consist of a propellant source, typically an air compressor or water pump, a sand container known as a blast pot, and a set of hoses and nozzles. The sand is picked up by the compressed air or water at the bottom of the blast pot and carried down the hoses and out of the nozzle. The nozzle is typically hand-controlled by an operator who can adjust the amount of pressure and the quantity of abrasive in the stream. In these applications, the sand or abrasive slurry is generally discarded after use.
Blast cabinets are self-contained sandblasting machinery types typically used for fine, accurate sandblasting such as in glass detailing. They also include the basic parts found in the mobile equipment, but feature a nozzle enclosed in a sealed cabinet. The operator generally places his arms through a pair of arm-length, captive gloves attached to the cabinet and views the work in progress through an observation window. The flow of abrasive is controlled using a foot switch at the bottom of the cabinet. These machines have the additional benefit of producing no dust and are economical as the sand is collected for re-use.
Blast rooms are the largest type of sandblasting machinery and are generally used to prepare large items or large numbers of parts. They consist of a big, sealed room with a honeycomb-grate floor equipped with a dust extraction and ventilation system. The sand is propelled in the same way as the other systems by an operator who works inside the room in a protective suit. Dust is continuously drawn out of the room and replaced with clean air, while the expended sand falls through the floor to be collected for re-use.