Also known as abrasive blasting, sandblasting is a surface finishing process that follows the same principles as sandpaper. Whereas sandpaper involves the manual rubbing of sand particles against a surface, sandblasting involves forcibly propelling a stream of abrasive material under high pressure onto a surface. As the abrasive material strikes the surface, it begins removing the top layer.
Unlike sandpapering, sandblasting provides a smoother, more even finish and can get into tighter, smaller spots that sandpapering can’t access.
Sandblasting can be used to create a smooth surface with few physical flaws and imperfections. It can also be used to roughen a smooth surface, create texture, shape a surface or remove surface contaminants.
How does it work?
Mobile or hand-held sandblasters have a chamber that is filled with sand, known as the blast pot. From this chamber, the sand is fed into the blasting line where an air compressor propels it down the line and out through a hand-held nozzle.
There are also larger, enclosed blasting systems known as blast cabinets and blasting rooms. Blast cabinets allow you to sandblast components in an enclosed system without damaging the surroundings or making a mess. Because the system is effectively a closed loop, the abrasive material is recycled, meaning less abrasive material is required.
Blast rooms are essentially larger scale blast cabinets capable of sandblasting much larger components or pieces of machinery like construction equipment or vehicles.
Different abrasive materials
Silica sand has been commonly used for sandblasting. However, it breaks up quickly and creates a large amount of dust, which can be hazardous when inhaled. As a result, it is illegal to use silica sand as an abrasive in some countries. Silica sand is sometimes treated with a resin to counter the dust and make it safer to work with.
Shot blasting uses small metal balls, or shot, as the abrasive media instead of sand. This shot can be made from stainless steel, copper, aluminum or zinc. Shot blasting is more abrasive than sandblasting.
Bead blasting uses fine glass beads as the abrasive media. Bead blasting is moderately abrasive and is used for more delicate surfaces that may be damaged by sand.
Other abrasive media include ground up plastic, ceramic shot, crushed nut shells or fruit kernels, soft abrasive like corn starch and dry ice and processing byproducts like coal, nickel or copper slag.
Sandblasting and other abrasive media blasting is used in a variety of commercial, industrial and DIY applications.
- Paint removal
Sandblasting can be used to remove paint, rust and other surface contaminants from a range of surfaces including cars, boats, houses, walls, machinery and many other surfaces.
Sandblasting can be used to clean a range of surfaces including grout and tiles, paving and concrete, walls, roofs, streets and walkways and more. Besides cleaning surfaces, it can also be used to clean tools, vehicles and machinery. This can include cleaning off debris, paint, rust and corrosion, mould and moss and more.
- Shaping parts and surfaces
Sandblasting can be used to remove burrs, tags and other irregularities from parts and materials without damaging their proper shape or structure.
- Smoothing or creating texture
Sandblasting is commonly used to achieve a desired texture on a surface. This may be creating a smooth finish on a rough surface, or creating a rougher, more textured finish on a smooth surface.
- Signage and lettering
Abrasive blasting can be used for lettering and engraving in a range of materials including stone, plastic and metal. This is used for a range of engraving and lettering applications including cemetery monuments and 3D signage.