Step 1: Layout and cut the pieces
we decided to pick up a power-shear from harbor freight. cuts the sheet like butter and leaves a cleaner edge than the hand sheers. it wouldn't work for really detailed work but for reasonably smooth curves it's definitely worth it's weight and even for straight cuts it's significantly more affordable than a floor shear.
Step 2: Fold and rivet the sides
remember that sheet metal is sharp. wear gloves, but don't be afraid to have fun.
Step 3: Attach magnets
Step 4: Baking a test pie
Step 5: Baking 19 more pies
the modular construction of the pie-cosahedron was a godsend in terms of cooking preparations. we pipelined 4 sub-pies per shelf in the oven, hit em with 75 minutes of baking at 350F and cooled on the counter-top while the next 4 went in.
remember to line the bottom of the oven with foil. things are likely to run over and the sugar burns on hard.