Re: Calienti, hot wax dipping!
The fluid is hot air from the chimney. Here again the more surface area the better. If you were to look at an industrial boiler you would see that the exhaust gasses run through a bunch of tubes that go through a tank of water. In this case you would want the tubes to go through a tank of wax. If you used standard boiler tubes like 2 inch dia you could get 6 or 8 going horizontally across the bottom of the tank. Putting in a double or triple layer adds much more area. The layers should be staggered.
Keith, what type of fluid is inside the double wall? How hot, how much time?
Zone 5a, Practicing non-intervention beekeeping