Jim baxter wrote:Many thanks Mike,and Allen. Using the steel was just for convenience. I had it on hand, and this heater is mostly to help me get familiar with the RMH. It only needs to perform this winter, then hopefully I will have learned enough to go full in building a good system. I have not even set the barrell assembly yet. I just built the burn chamber assembly, and tested it before I completed the heater. I will get picture tomorrow. I do have a 10" pipe to encircle the heat riser, and plan to insulate with perlite. I also planned to run only 15 to 20 feet of pipe for heat collection. Also, concerning "cob." Is is acceptable to mix in some straw with the sand, brick, and clay? Thanks again for the help, and by all means feel free to give me the "skinny" on do’s and dont's. I am certainly trying to learn. I was just hoping to put together a unit to assist me in doing that.