Since the RMH workshop I’ve been tossing around ideas for my installation. With rocket mass heaters, the devil really is in the details. They’re super inexpensive to build if you can scrounge the parts and innovation is rampant and lauded IF it works.
The mock-up of my stove encourages me to find a larger diameter riser. The 6″ well casing I have will work, but bigger in my case may be the difference between marginally functional and awesomely functional. Ernie’s suggesting an 8″ core and I’m agreeing . . . bigger in this case is better as long as I don’t go above 8″.
I put a “want” out for 8″ well casing on our local freecycle and our County’s 2Good2Toss. I’m not really expecting any results but I have to try. I probably shouldn’t be fussing about this as the installation isn’t going to be a long term one. I could use 8″ stove pipe. It’s certainly more readily available, would easily last the couple years I need it to and I know where the scrap pile is for our local stove store. But you know me, I’ve always got to say “what if”.
Logging is big in our area. Short lengths of log truck reach (3/16″ thick 8″x6″ tubing) are pretty readily available. With Wadly’s connections I could probably score 50+ inches of that fairly easily. So the question is, can I use 8″x6″ steel tubing for the riser? What effect will the rectangular shape have on the draw/draft? I’ve posted queries on the RMH Experimenter’s Corner and and on the Permies Alternative Energy forum. I won’t hold my breath waiting for answers.