re rallye wheel resto sandblasting rod waligora tom buddie hit the nail on the head when he discussed sandblasting a very good friend of mine is a year coatings blasting professional some of his work includes blasting turbine blades where texture actually lack of any change is critical we have had numerous discussions about blasting and coatings and the outcome has always been that most damage to the part being blasted is caused by the incorrect blasting media not home depot sand the incorrect pressure or incorrect technique used while blasting i have blasted under supervision of this friend numerous parts including frames suspension pieces small fiberglass parts yes fiberglass parts and numerous aluminum pieces and have never damaged a part i have always consulted with this professional before any work was started and he has always guided me correctly so to those that have had problems you might try to ask a few questions of your blasting shop before they proceed to see if he understands that surface finish is critical to you if he responds i use silica sand for everything i suggest you look for another shop as a very rough guide for heavy gauge steel ie whels frames suspension try using duponts starblast at about to lbs pressure and avoid perpendicular to surface blasting better to blast at degreees angle do not stay at one place and give it hell or this stuff will bite starblast is also great at removeing heavy rust as it is so fine that it gets deep into pits but a little more pressure time might be required this stuff is available at any commercial blasting supply store look in yellow pages under sandblasting supplies this stuff is also great in blast cabinets many other products are available for different substrates but this was not meant to be a forum on balsting techniques however if used correctly blasting will provide a suface finish that is clean and adhesion promoting to top coatings hope this helps