Glass Bead Peening
A blasting process using silicate glass beads as abrasive media to produce metallically clean surfaces without significant material removal. It serves for optical enhancement and slight densification of the marginal zone.
Glass bead blasting is a cold process: the glass beads are shot onto the surface with compressed air and act like a fine hammer. This removes scale, rust, and old paint without heating the part or removing material. The surface is uniformly roughened and slightly work-hardened, which gives a clean, weldable surface for welding. Just be careful not to stay too long in one spot or use too high pressure. Otherwise, you can embed the glass beads into the surface or exaggerate the roughness, which will make the weld dirty. After blasting, you must thoroughly blow off or sweep the surface so no blasting media residue gets into the weld.