I’ve been lurking for over 5(?) years on this forum ...and the time is finally come to post. I’m building an 8sided sauna in my backyard. I was planning originally on having a rocket mass heater inside (with the feeder box outside , to keep smoke out), running pipes under the benches on the inside. But... I don’t know what size would be optimal. I want a stove that heats quickly and absorbs heat well So the heat from the exhaust pipe is cool...but the actual area of my sauna is so small… Could I get away with a j6 inch system? I don’t want to build a system that burns too hot if I don’t need to.What are your thoughts ?👍🏼🙏🏼😀
Hi Vince; Welcome to the wonderful world of rocket science!
A 6" J tube will be plenty for your sauna. You may want to cob 50% of your barrel to slow down radiant heat.
If I read your design correctly it appears you are right around the 30' of pipe recommended for a 6" system.
Have you considered "bell" benches in place of piping ?
Take lots of photo's as you build, our happy crew of rocket scientists is eagerly awaiting guiding you on your first build.
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posted 2 weeks ago
Thank you Thomas! Actually I was wondering about purchasing (or finding) plans to do a small bell style rocket stove or a 6 inch J tube style rocket stove… I’ve heard of Ernie and Erica’s j-6 plans somewhere on these forums, But I have not heard of another stove plan that is thrifty on wood but also warms up fast. Maybe the cyclone bell rocket is in the running— a stove that was covered in a permies video that I saw a recently. Is that what you were referring to? Is there a tried and true trusted plan for a stove like that by chance ?
Lastly, is there a rocket stove version that heats up very quickly? My sauna is small, will be thoroughly insulated via clay slip or lite straw clay , With 4 to 6 inch wide insulated roof/walls... should be able to hold the heat for a couple hours of a sauna session. 150-180° tops target temp in room.
Given the fact the size of the sauna is so small, would a 4inch tunnel design cyclone bell style work? How small could I go ? I feel a 25 gallon barrel would be over kill. Thoughts and opinions welcome 🙏🏼 Thank you all !
I have been a part of two wood heater saunas. The second was a small sauna with a 4.5" batch rocket. The thing cranks to 130c with that heater. We find that between 65c and 80c to be a good balance so it is more than enough power.
Yours is a lot larger but I would think even a 5" would do the job.
Adding mass will cause it to take a very long time to heat so I would advise just using a barrel with some rocks on top. That way you can still use water on the heater but get instant heat when you light the fire.
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Switching from electric heat to a rocket mass heater reduces your carbon footprint as much as parking 7 cars