Steel shot or grit is one of the commonly used abrasive materials in blasting procedures. The steel is mixed with high pressure air and shot at the surface. When the spray of air and shot is directed at the paint surface, the shot chips and flakes away the paint, metal scale and other surface imperfections that can complicate a painting or coating project.
Since this surface preparation method uses steel shot, the blasting action leaves behind a rough surface which can assist in coating adhesion. However, the steel shot does remove enough of the surface material to make a difference in environments where tight physical tolerances must be preserved.
Steel shot is very durable and the same blasting material can be recycled and re-used. However, to exploit this capability, the steel shot must be kept dry to inhibit the formation of rust on the shot material.
Sometimes, the steel shot is replaced by other metals, such as aluminum. Using softer metals for abrasive cleaning results in a smoother substrate, which may be desirable for some types of materials or finishes.
Shot blasting is especially useful for preparing floors for refinishing. The abrasive action of the steel shot can strip away the types of paints which are used in flooring applications. Steel shot is also able to strip away the residue of glues and other materials used to bond tile and other types of flooring to the substrate.