I bought a hopper bottom grain trailer that holds about 350 bushel to pull behind our single axel dump truck. It needed some work to repair some rust and we are going to paint it up. The bottom on the hopper was rusted out so we cut the bottom out and welded in a new bottom. We then sandblasted the entire trailer, box and frame. Priming the box and extensions. The frame is painted.  The box and extensions are painted. Done! We haul 300 bushel in the trailer and 200 bushel in the truck.