Bead blasting is a form of high pressure cleaning of a surface that is less damaging to the surface than typical abrasive blasting using small sharp particles such as quartz sand. One of the most common materials used in bead blasting are small spherical particles of glass that are shot with air pressure at a surface to remove coatings, or to polish it, but other types of bead materials are also used in the process, such as silicon carbide and stainless steel beads. While ball-shaped glass beads produce the smoothest finish to a surface, ground quartz can also be used to give it a more shiny, coarse surface that is easier to coat with paint and is more electrically conductive.
Air bead blasting is a fine method of cleaning metal surfaces such as aluminum, stainless steel, and titanium used in the automotive industry, and softer metals used in jewelry and other decorative parts such as brass, silver, and copper. It's considered a low-cost process because the beads themselves are relatively inexpensive and the air pressure equipment can be powered in the same way as common pneumatic tools. The process is used to clean corroded metal, to remove cosmetic flaws, and to prepare surfaces for paint or other coatings.
In glass bead blasting, the beads are made from a lead-free, soda-lime type of glass that will not harm the environment or ground water if bead residue is washed off into the water supply. Much of the bead material that is used in a blasting process can also be recovered by vacuum systems, and the beads are durable enough that they can be recycled into the blasting process up to 30 times. The finish produced by using glass bead blasting is known as a satin look, which is a medium-level cross between a dull finish and a high-gloss finish.
Where bead blasting is meant to do minimum possible damage to a surface, it is often referred to as peening. Peening is used to clean wood as well as metal, and other materials that would be more prone to breakage in the blasting process than metals such as concrete or ceramic tile. It is also commonly used to clean very thin metal connections or welds where eroding the surface material could otherwise damage structural integrity or the viability of an electrical circuit. A bead-blasted surface also tends to be hardened through compaction, especially in the case of metals, which gives it increased fatigue resistance and better resistance to future scratches or other deformations.
Wet bead blasting is another variation on the process of bead blasting that uses both beads and a stream of water. It requires less energy than typical air blasting methods, and allows for easier clean up of the beads as they are mixed into the water. It is commonly used to clean various types of building stone, including hard stones such as granite, flagstone, or concrete, and softer stones like sandstone and clay brick. By combining the two materials in the blast process, low pressures can be used with ordinary tap water, and any unrecycled residue is considered safe for disposal in residential landfills.
