jim rozen wrote:
In article , Ian Stirling
says...

Polished hardened steel former, silver sheet + big hammer.

2cm^2 of silver sheet is cheap.

Doesn't the silver tarnish rapidly? I would think you would
be better of with aluminum.

It's good enough for prototypes.
Aluminium is much harder to polish to a mirror finish, and really wants
to be vacuum deposited.