One way to build a homemade barbecue grill is to use a 55-gallon drum. The first priority is to obtain a 55-gallon round metal drum or barrel that has never contained any hazardous materials. The barrel should be thoroughly cleaned with hot water and soap, and dried before proceeding with the construction.
Mark the centre of the diameter of the drum top. Mark the drum all the way around so it is in two halves. Before marking, position the bunghole (located in the drum's lid) so that it will be located in the centre of the arc when the drum is cut in half vertically. This can be used as an air control for the fire and a clean out when cleaning the barbecue. Save the threaded cap if it is available.
Cut the drum on the line using a circular saw with a metal cutting blade or a cutting torch. Wear safety goggles.
Lay the drum half with the bunghole on its side with the open end up. Brace it with blocks so it doesn't roll. Save the half without the bunghole. It can be used as a lid if desired.
Attach 1-inch angle iron, with one flat side facing up, to the top edge of the cut line on the drum. Use nuts and bolts or weld it in place. This is to brace and hold the grill. The angle iron should run the perimeter of the opening for the grill.
Turn the drum over with the open side down. The barbecue will be upside down at this point.
Attach two legs to each end of the drum using steel flat iron 2 inches wide or metal 1 inch pipe. Cut the legs at a length that will make the barbecue height about 36 inches off the ground. Attach with bolts and nuts or weld on. Attach the legs evenly so the barbecue does not wobble when standing up. Wheels can be attached to the legs on one end using nuts and bolts to make the barbecue easier to move.
Obtain a metal heat-resistant grate or premade grill for cooking. The size should be slightly smaller than the opening of the drum.
Lay the grate or grill on the angle iron attached to the drum in Step 4.
Take the other half of the drum and attach four heavy-duty metal hinges to it with nuts and bolts or weld on.
Attach the half with hinges to the barbecue half of the drum in the same manner and use it as a lid or cover.