In preparation for aluminium bending I did a quick search on the Internet for a simple and low cost bending brake. I built this and had formed my first piece of aluminium channel in 1 hour.
Using oak timber, door hinges, right angled steel, a cut off gal stirrup for a handle, a few nuts and bolts and clamps to hold it in place,
Bent a test piece of aluminium with 1/4" high sides, 1/2" wide at one end and 3/4" at the other.
Scored a line using a Stanley cutter with the curved blade a few times and then just bent and snapped the piece off.