I got about 60-70% of phase 2 fab finished (the aluminum skins).
Here's some pictures to follow along (howto - style).
Not shown - I assumed the edges of my aluminum sheet were square, and transcribed (x,y) points from the drawing using a pair of tape measures from the edges. Then cut it out with aviation snips.
(I decided the plywood back piece is just a template.)
I used a 2x4 and a hammer to make this first bend. It was messy, so I tried planishing, but that was a mistake.
A better way to fold .032 Al is to sandwich it with 2x2's - wrist strength is fine for a .1-.25" bend radius, even progressively across a long fold. Also, this shot is after transfering the back template and snipping it out.
Next I want to attach the skin to the frame, so I lay it out, align it, clamp it, and use a pair of fridge magnets to find the edges of the frame.
After all the edges are found, I had a trace of the frame on the bottom side of the sheet. Add some 10 lbs weights to keep the metal flat (also still clamped), and then drill all the holes for 1/8" rivets.
Next it's important to disassemble and debur the holes. I used a larger bit for deburring. I also applied construction adhesive. I figure if it doesn't add any strength it will at least keep it quiet. Here it is all riveted.
For the sides, first I put as much of the 4" radius bend into it as I can, by hand. Then sandwich and apply folds for the lip on top. Then clamp, drill, debur, glue and rivet the side-rib, made from .75x.05 aluminum right-angle.
I'm not achieving art-quality metalwork (I presume due to inexperience and/or impatience), but my wife says it looks good, and that's the crucial test here. Moreover the plan feels right - the pieces feel strong enough where they need to be.
(So far.)