4-inch PVC coupling pipe. 4-inch x 24-inch PVC pipe. This is the combustion chamber. 4-inch to 2-inch PVC reducer. 2-inch x 48-inch PVC pipe. This is the barrel. PVC cleaner and cement.

Acquire an empty 5-gallon drywall bucket, 1- and 4-inch-diameter PVC pipe, a 4-inch flat PVC end cap, pipe fittings to reduce the 4-inch diameter down to 1 inch, a 1-inch tee fitting, PVC solvent ...