I use 8" C-purlin for fender material by notching the sides and folding at approximately 45 degree angles +/- before welding the cuts back together. Then I weld 2x2x1/4" angle stub outs off the trailer frame to set the fender on. Makes a nice looking, very sturdy fender that will take abuse. You can stand on it, sit on it or use it for a small table. Works for me.
