[MARTINSR]

By the way, it doesn't warp metal as I thought for years and many others think, from heat. When you are sand blasting in the dark you will see sparks as the sand hits the metal, that sort of thing is what gives us the idea that it's "heat" that warps the metal. But it is not heat at all, in fact if feel metal after you sand blast it it's often cooler because you have been blowing air on it.

No, what causes the warping is that each one of those little rocks that hit the metal is like a little hammer. They thin the surface of the metal where they hit. So when you hit the metal with millions of pieces of sand you are hitting it with millions of little hammers thinning out the top layer of the metal! When the underlying metal isn't thinned, it warps the metal. Of course if the metal was being thinned all the way through it would warp it too, just different than what the sand does.

Just be careful, be sure you know they know what they are doing before you hand over those treasure body parts to them.

Brian