My brother made this one. He welded up a steel box. Added a steel box to the bottom and installed 2 220 VAC hot water tank heater elements. Only one is hooked up to power and the other is extra so the tank does not have to be drained in the event of heater failure. Since these pictures were taken, I added 1" insulation board all the way around. This has been used to clean many engines in my shop.