Metal working question

[Rob]

I've seen many times where aluminium was used to create doorpanels or other
panels.
Anybody hear have experience with that ?
I'd like to know how they make those 'folds' or 'indents' in the panels
to make them more rigid.

Also, how do they work with it without denting it ? Can you actually
straighten it ?

Last question, anybody know where to get an electric sheet metal nibbler (cutter) ?

Thanks.

Rob