On 17/10/2014 01:32, Lostgallifreyan wrote:

I usually get round that lack of knowledge by using a good hard edge on the
inside of the bend and also one on the outside, then hammer gently on the
outer bar held right onto the bend to press it against the immer supporting
bar (or vice edge, whatever I can make fit). It's a bit tedious, but can
result in very nice clean and sharp angles at 90° regardless of metal used.
Penalty for error is usually no worse than a slight thinning at the crease.
I've considered trying to build a DIY tool based on a good quality hinge, but
never done it.

Some lightweight alloys I have used have cracked on a sharp edge. Often
I just use sheet steel a blowtorch, flux and braze it together. A LOT
easier than bending without the right kit.

Andy