We have two brakes.........one that my Son built and one that is a commercial unit that we bought. The homemade one didn't work out so well, especially when we tried bending up heavier stuff like 18 gauge. Even though we reinforced the jaws quite a bit, they would still flex and not keep the metal tightly clamped while bending. It was ok, but not great.
Then we bought a Grizzly 48 inch brake and it is tons better. The clamping jaws are heavy cast iron so they don't flex at all, and you can remove some of the segments so you can bend up smaller pieces and the lips will clear.
I only mention this so that you are aware of what areas need to be really strong to make one of these work well.
Don