I use old propane tanks for my slack tub(30lb) and oil quench. I just cut another 30 lb apart(top, bottom, and then in half) so I could put a 100w light bulb under the water and a hot plate under the oil(warm oil is beter than cold for most oil quench steels) Just cut a keyhole in the side so I could put the outdoor fixture under it. Ill put the light on at night when not in the shop to keep the water from freezing:)
I get the old propane tanks from a friend who works for a propane company. They take the valves out and wash them out for me with water. Then I let them sit upside down for a month or two. Completly empty when I start cutting.....If you dont know...NEVER cut into a propane or other type of tank without being completly sure it is TOTALY empty and depreasurized. Big BOOMs suck:(
Drogo