Originally Posted by stuckinatx
since the powder is charged and bonds electrostatically, why is it so important that the undercoat be blasted to remove paint and the like?
Because the powdercoat cures in an oven at 400° F and old paint left beneth the surface will likely blister and burn. Also, the powder coat is paint, just in dry pigment form. It needs an etched surface for proper adhesion.