The main function of corundum blasting, also known as sand blasting, is to clean a surface of paint residues, oxidation or to smooth scratched or marked surfaces. This is a mechanical treatment using corundum at high pressure as abrasive shot. Given the hardness of corundum and the variety of grain sizes, it is possible to achieve both polished surfaces and high roughness. The usual roughness Rz for treating metal parts with Teflon® is 1 to 8 microns.