JF, choose your media carefully. Sand is extremely abrasive and will heat the metal fast. I put the small lumps of rust in a glass bead cabinet and still had to be careful not to stay on one spot too long. If you have light rust and old paint, you can use soda or plastic media and not worry (much) about heat warping. Glass beads let me see the cast GM part numbers on stuff I could barely identify as a part; is this the level of abrasiveness you need?
The cabinet we've been using is powered by a huge compressor (plumbed through entire shop) and has a pressure regulator on the air inlet valve. We can change pressure and tips for different media, although the cabinet is old and anything finer than glass beads leaks out the corners. :rolleyes: Ear, eye, and respiratory protection is a must.
