IKEA
- Article number EMU0507 or EMU0518 - tin plated steel box, 2 pieces one
inside the other. 9.90CHF in Zurich. Size of a shoebox, suitable thickness.
You can make many boxes if you buy one.
Czech Republic
- Ferona Praha Holesovice,
U Pergamenky 11, Praha 7. They have aluminium, copper and unplated steel. You
have to take at least 1x1m square.
Switzerland
- Dynamo Metallwerkstatt Zurich
has a limited assortment of various steel and aluminium plates. You can cut on
a guillotine or with plasma and bend on a bending machine.