I just bought a 120 gallon smoker on a trailer from Dave's Custom in Riverview Florida. It didn't have a fire box, so let the fabrications began. We cut the smoker off the trailer and turned it around. We also extended the fenders out 6 inches. Using the pit calculator we are constructed a fire box, cut the end off, and the steel plate will also be a water pan. Here are a few pics of the work so far.