I used my dremel to cut my case up as well, and I'd recommend getting their fiberglass reinforced ones or whatever they're called. Those worked the best for me and lasted the longest. Just don't grind into the steel to hard or you'll get the wheel too hot and that's when it'll really wear down. Looking forward to see more of this case.
Of course I was going by what it said on the box
Going to lowes guys, getting the strongest head i can find.
EDIT: I might not be able to get it today... Anyways, I'm going to start sanding the big piece.