Just to share my experience. A seasoned restoration guy told me the reason sheetmetal warpage is a problem is due to the old paints and materials that are hard to get off and the blaster has to stay on it a long time adn the heat warps. I did as he suggested and stripped my whole car wiht a putty knife and a couple gallons of aircraft stripper over the course of a weekend out under a shade tree (with plenty of cool beverages in teh cooler). The sand blaster charged me $500 for entire car, in and out, top & bottom, everywhere line of sight. No warpage, perfect clean everywhere and I had it blown out a bunch and immediately shot with epoxy primer. I was really happy with all that. Now, that was several years ago, so I imagine that $500 would be more like 800 or so now I guess. Just sharing from my one experience, and boy it takes alot of air compressor use to get all the sand out of nooks and crannies.
I have done a bit of heavy duty sand blasting and never felt a panel even get warm let alone get hot enough to warp. I have deformed panels by blasting, but that happens from being too close or staying at one place too long. Think of a sandblaster as 10 billion tiny hammer blows. Stay too long and they add up to a dent.
Carl
