Gravity-fed sandblasting machines are an economical and easy-to-use alternative to larger machines or cabinets. With a gravity-fed, or siphon unit, the media fills a vessel along the top of the sandblasting nozzle. When the unit it turned on, air pressure changes within the machine to create a vacuum effect, which pulls sand or other media down into the nozzle. From here, the sand mixes with air before it sprays out of the nozzle and onto the surface being refinished. These machines offer a high degree of portability, but tend to be more efficient on smaller projects.
Pressure-fed sandblasting machines rely on a separate air compressor for power. A tank filled with sand may be built into the machine, or attached via hose or tubing. When the air compressor is switched on, it draws sand from this tank into the nozzle, mixing it with air to create an effective blasting media. Units powered by an air compressor provide a much higher level of power and force than gravity-fed units. Though they tend to cost more on average, they also allow users to blast larger surfaces more quickly. While these units are still relatively portable, the addition of a separate air compressor may make transportation more difficult in some applications.
Wet sandblasting machines combine water with sand or other media to create a virtually dust-free method for cleaning, paint removal or refinishing. Many of these units utilize an air compressor for power, but are designed to also pull water into the nozzle rather than air. Wet sandblasting machines generally offer easier cleanup than air-based models, and are an important tool for projects involving hazardous materials such as lead paint, asbestos or silica.
Blast Cabinet or Room
Blast cabinets serve as an effective machine for sandblasting small items such as automotive parts or miscellaneous metals. Rather than spray air and sand into the air, users place these items into the cabinet and shut the door. When the unit is turned on, air and sand mix together to blast the part from many angles within the cabinet. This helps to reduce the mess associated with sandblasting, and serves as a common application in home workshops or small garages. Blast rooms utilize a similar operating principle, but are designed to send sand and compressed air throughout an entire, well-contained room rather than a cabinet. Users can clean or refinish any object that can fit in the room, including vehicles or large equipment. In this case, the room itself acts as a type of sand machine.