I am in the process of designing a rocket stove for the purpose of making maple syrup. My plan is to make a 6" system with a 55 gallon drum as a bell. I recently purchased a shallow stainless steel pot 20" in diameter and 8" deep commonly called a brasier pan that would be used above the riser as an evaporator pan. I figured for $100 that it was a better option than fabricating my own without all of the welding. I was assured from the distributer that the pan was 100% stainless, only to find out upon delivery that the pan is actually tri-ply with aluminum sandwiched in the bottom. My concern involves the temperature that would be achieved 2" above the riser where the pan would sit. I would cut the lid of an open top drum so that the pan would be in direct contact with the heat. I have heard of crazy high temperatures inside the risers that melt steel. Does anyone know the temperatures that I would be anticipating? And would the pan I currently have be a cause for concern?
I had a traditional 2x4 evaporator that served me well but I quickly grew tired of feeding that hog and watching all of that heat go out the chimney. The sap is flowing, time to make a better system.
Depending on how insulated your core and heat riser are the temps could be dramatically different (not very insulated 1000F+ to very insulated 3000+). Even on the low side, I think it would melt the aluminum. I bet you could find used beer keg and cut the top off for this application (they are usually stainless steel).