I just built a bumper for my rig. The factory POS brackets went in the garbage!!!! What the hell are those supposed to do? Might as well have no bumper at all! I understand the whole aborbing the impact theory... but wholly crap! those things are nothing but decoration.
I made new 1/4" ones and welded them to the frame. I cut some holes in them so they would crush under impact...(from a car, not a shopping cart!) I'm eventually going to put on a winch, so I had to at least make something that wouldn't tear off the front end.
Anyways... good luck with you project man! I would deffinitely consider running it by a good welder though. tinfoil bumpers aren't good!
Take Care, Clay