I use 90 PSI and higher with a pressure blaster all the time on seams such as that and warpage does not seem to be a problem, I don't think it would be on those parts in the pics either. I have had some serious warpage problems in the past but that was on flat surfaces and I have warned repeatedly about that. I have found aluminum oxide to work extremely well in removing rust from pits and in fact it works especially well on separated seams where the rust is usually quite deep.
ps play sand makes you miserable for a while and then it kills.
Last edited by oldred; 12-23-2006 at 10:43 AM.