i am building a smoker out of a 55-gallon drum. i am going to lay it sideways, with a 19"x23" rack to place the meat on. i have the grill part built. now i need to build the firebox. how big should i make it? i planned on connecting the firebox to the food chamber via a pipe, probably 6", with a damper in it (like the chimney on an old wood burning stove). i am going to use some sheet metal (diamond plate) to make the firebox, and to make a deflector plate to keep the temp even in the food chamber. i have the smoke stack just a hair above the food rack, on the opposite end of where the firebox will be. i used the hole already in the "lid" of the drum. i screwed a 2" nipple into the hole, and screwed a 90Â° elbow on it. i need to get a 2" diameter pipe to finish the smoke stack. the only parts i have to buy are the smokestack pipe, the pipe to connect the firebox to the foodchamber. and a thermometer to add to it. everything else i got from work. i used 1" square tubing for the legs. 1" angle iron to make a frame for the rack, and expanded metal for the rack. i am also going to use 1" square tubing to hold the firebox to the drum itself. i will make a shelf to mount to the front also. any suggestions on the firebox?