What’s the easiest way to go about bending the metal as close to 90 degrees as possible? I tried a vice but… well… that didn’t turn out too well.
What is the material, size, and thickness?
Judging that it’s in the FVC forum, I reckon that it’s the bar that comes in the kit.
I read a trick in Make: Magazine about bending metal. They suggested two pieces of angle iron clamped together, one of them being at the edge of a workbench or table. With the two sides clamped together, you can bend the metal to your liking. (And the verticalness of angle iron makes the whole 90-degrees thing pretty simple.)
Hope it helps!