[Crex]

Jim, might try going over to the ABANA site and look through the tutorial section. Lot of ways to convert many different salvage items to charcoal forges. As with anything there are certain things you have to be aware of and pay attention to in order to fabricate a workable forge. Read a lot before you start and you will get better results.
BBQ grills are usually made from lightweight materials and will take some pretty good lining material to handle the heat without bottom burn out. All kinds of easily found material can be used but will needs to be installed properly - again studying up will save you some grief and time.