Shot Grit Blasting SA2.5 & SA3
We’re experts at shotblasting and want to blow you away with our expertise!
Shotblasting is a means of cleaning steel by blowing an abrasive media against the steel using compressed air, or mechanical means to propel the grit.
Historically, the material used for artificial sandblasting was sand that had been sieved to a uniform size, and hence the term ‘sandblasting’. The silica dust produced in the sandblasting process caused silicosis after sustained inhalation of dust. Other materials for sandblasting have been developed to replace sand; for example, steel grit, steel shots, copper slag, glass beads (bead blasting), metal pellets, dry ice, garnet, powdered abrasives of various grades, powdered slag, and even ground coconut shells or corncobs, walnut shells, baking soda have been used for specific applications and produce distinct surface finishes.
For coating applications, there are two main surface contaminants that need to be removed. Millscale is the grey flakey oxide of iron that’s present on hot rolled steel. It only forms at high temperature in the hot rolling process, so is not present in cold rolled steel. For most coating processes this must be removed, otherwise the coating only adheres to the oxide, not to the steel, and adhesion is reliant on this poor bonding of steel and millscale.
The other oxide is brown, commonly called rust, and must also be removed. The extent of rust depends on time and conditions of storage, and can represent even millimeters thick deposits. It all must come off.