I cut a notch in a short bar of Peek in order to use it to bend (pry) a consistent 45* flange on the front and back edges of the rounded center section of the fuel cell. I was afraid that this method might cause warpage to the rolled section, but it worked great. Rather than attempt to make a continuous bend, I simply spaced the initial bends about an inch apart and then came back to bent material in between each original bend. It took a little finesse to get a uniform flange all the way around, but it wasn’t hard to do.