The heat source is my crab cooker. The boiler is a shallow well presure tank, free from my local plumber. The box was built out of salvaged 1x4 that wasnt good for much else. I did spend four dollars for the radiator hose to bring steam from the boiler to the box. It's crude. It works. It's fun to play around with steam-bending wood. At first give yourself enough extra stock so you can experment, and don't get upset if some of the wood breaks, sometimes it just does, I've had pieces from the same stick of wood behave totally differntly,one bends like putty, and the other shatters, both with the same cook time.
Bob