A polyethylene shell provides the main structure, while also protecting and insulating all the internal components. Roto-molding foam-layered PE provides optimum structural stiffness and thermal insulation while reducing tooling costs and material waste. The Mixing tanks, pumps, piping, and heating element fill the shell interior. A pull out tank collects the glycerine by-product, which may be easily transported and disposed of, or used for making soap.