Exactly, the testing I did was to work out the effects (positive and negative) of various media/pressure/nozzles/patterns on different materials and masking material. So we ended up with curves to follow, what media and what pressure, to maximize cleanliness, minimize cycle time, minimize damage.but that isn't the blast media or the blasting process at fault, that's the corrosion. the thickness you loose to that mechanism directly proportional to how fucked the metal is.