We used to use a old chevy oil pump shaft to roll the fenders on race cars. You can buy metal forming pliers made just for what you want to do. If you have a old set of vise grips, just get a couple of pieces of flat bar and clamp together. Then weld flat bar to vise grips and you have a ready made edge bender. If you bend it a little at a time until you get it bent over 90degrees, you can take a hard plastic mallet, rubber hammer, ball pein, body hammer, etc and hammer the bend flat giving you a folded edge. Just dont try to hammer it flat in one pass, just tap it down going end to end until you have it all the way flat. Hitting the folded edges hard while bending will result in metal stretch and a wrinkled finish.
