I don't know what abrasive they used, but some of our stuff was blasted for painting---the guy actually was VERY knowledgable and had done many raqce/show cars--he blasted in a pattern--took off the stuff in layers reverse order of application---lettering first, then top paint coat, working in sequence down to primers and then bare metal--didn't strech or deform any thing including thin aluminum and magnesium panels-----but he was one guy of thousands------------

And then there was the place near us in Elburn, Il that used COAL particals to blast garbage dumpsters, concrete trucks, etc---------