I'm ready to start building a small-scale WMO Filtering setup out of a beer keg. Metal 55 gallon barrels shouldn't be hard to find, but so far they are. Since the keg is aluminum and I only have a 120-volt flux core welder, I can't weld in bungs to hold the water heater elements. But, I've read that they can be simply dumped into the oil and turned on since oil is non-conductive. Somehow I don't believe that. My WMO is primarily used motor oil thinned with small amounts of gasoline.