The finish achieved by shot or grit blasting is highly dependent on the size and shape and material of the shot or grit used. The most frequently used material for fettling zinc diecastings is round aluminium shot between 0.6 and 0.8mm in diameter.
Preparation for painting or powder coating is sometimes preceded by blasting with synthetic corundum or with glass balls 0.2mm to 0.4 mm across or with very fine angular steel grit.
Small castings are often tumbled in a barrel simultaneously with blasting; this serves to ensure that all surfaces of the casting are exposed to the shot or grit blast. Larger parts are attached to fixed or rotating jigs.