Propane tanks can be obtained in almost any size, from portable 5-gallon units to 500-gallon home tanks. All are cylinders with rounded ends, made of sturdy steel. Any size tank can be converted to a smoker that sits either horizontally or vertically. The tank must be divided into two sections: a firebox for charcoal or wood and a cooking area with a grill, with some baffle between to direct smoke, not flame, to the meat.
Building a barbecue smoker from a propane tank requires welding equipment and expertise and some experience in metal-working to fashion legs, install hinges and accessories. A cook who lacks the equipment can usually find a welding shop that will do the work to his specifications.
A major problem with converting a propane tank into a smoker is the risks of working with propane. Propane is an extremely volatile material which explodes easily, so great caution is required in cutting a tank open. A standard method is to empty the tank completely of propane, then fill it with water and let it sit for a few days. Some smoker builders suggest draining the tank and refilling it with fresh water before cutting into it with a welder's cutting torch in order to cool the metal and reduce danger.
A tank can be split vertically or horizontally. One style of propane tank smoker uses an upright tank, with one end cut to make a lid and brackets welded inside to hold a fire pan, a water pan and a grill. This creates a water pan between the heat and smoke source and the meat, which helps keep the meat from drying out.
Other varieties of barbecue smokers split a tank lengthwise, set it on an frame of welded angle iron and add a center baffle to divide the firebox and cooking area. This style usually uses larger propane tanks, the sort installed at homes or in propane-powered vehicles. Usually a chimney is installed on one end and an air opening in the other in order to create a flow of air to direct smoke from the firebox into the cooking chamber. Some styles combine two tanks in an offset style smoker.