Normally I would have just bought some aluminum boxes but the prices are ridiculous, and I did not have a finger break to make my own. Having no real metal brake, I had to improvise. and the results were better than I had hoped for. So here is what we did:
figure 1. First bends
figure 2. After clean up.
3 pieces of square steel tubing 2 of them about 1 foot, the other maybe about 2 feet.
Optional 2 1/2"x20 blots about 3" long and nuts.
Large deep through vice.
Demel with an abrasive disk.
Dead Blow Hammer
So mark your metal mine is .004 sheet aluminum.
Align and clamp between the two shorter tubing.
You could drill two holes one at each end for nuts and bolts 1/2" x 20 or bigger hardware tack the nuts in place align and tighten.
place in vice long end up and tighten.
Using longer tube push on the aluminum plate at the bottom. (hence the term gorilla) (fig 1)
Then to complete your bend to square it using a Dremel with an abrasive disk to score it on the bend line. (if I had done this step before the bend there would have been less bow and the angles would be closer to 90 degrees.
Then clean up with dead blow hammer on square tubing.