I hit a road block with my engine house project. While the first part went together pretty well the roof has really vexed me. I want a removable roof to show off the detailed interior, and it had to be strong enough to withstand handling.
So, I first purchased a sheet of 0.012" thick brass on Amazon for about $15 which was 10" x 12" wide. I cut it to size on a paper cutter, and then bent it on a homemade "press" consisting of my desk edge, a 2x4 piece of lumber, and a tiny hammer.