Sheet Metal Forming

[Roy]

I'm looking for information, here. I've been thinking of making a San Francisco California Street cable car in brass, and I'd like to form the compound-curved lower roof from sheet.

I gather that hammering over a hardwood form is the traditional technique. I inherited my mother's and grandmother's jewelry making tools, including a tool steel cube with semispherical depressions of various diameters. I know it was used for hammering spoons, tea balls, etc. The only similar work I've done, was hammering boiler ends for an O gauge live steamer. I hammered a brass sheet disk over the end of a round aluminum bar. I had to stop and anneal the disk several times.

On Mythbusters, Jamie Hyneman used hydroforming to make a torpedo casing from sheet. I've wondered if this could be used, for model making.