I learned a lesson about sandblasting on my Nomad. I chemically stripped the body panels, but the window and door openings with all their tight bends, etc. were difficult to do. Plus I didn't want any chemical stripper left in any nooks and crannies. So I blasted those areas.
After blasting the edges of my hood I decided to blast the rear hood brace. I should have put a sheetmetal protector between the brace and the outer skin, but I tried to be careful not to blast the underside of the skin. I was using pretty low pressure....probably 80 PSI or less at the blaster, and 80 grit silica sand (don't lecture me on the health effects please ). My hood was virtually perfect.
Here's a pic of the underside after blasting:
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I also did the same with the roof brace....notice I barely hit the roof skin:
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After priming I started blocking the parts some time later. I was baffled as to why I had a big dip at the back of the hood. It was literally 1/16" deep and I had to bodywork it and use Slicksand to get it back to where it should be. I couldn't figure out why it was low there for quite a while.....I think it was when we were discussing a trunk lid that got ruined by sandblasting on the other site. Then it hit me. Also, when I blocked out the roof there was a slight low spot in front of the brace. I'm convinced that you should NEVER touch flat sheetmetal with a sandblaster, no matter how "careful" you are.
Here's the hood after blocking Slicksand:
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Bodyworking:
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Finished:
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