Randy Hardwoods

It works, not perfectly, but it works well enough to keep my 19 x 12 kit greenhouse heated through the the rest of March and April. More importantly I learned enough to think that I can heat my 20 x 40 next winter with a better build. I will be scouting and scavenging materials all summer. Going batch box, 8 inch for the next one, horizontal barrels of water over the exhaust, plant tables over all that. Between some passive solar,a RMH, and insulation I think it can be done. I have researched the life out of it and I am not done reading yet. None of it would be possible without this forum and the people on it. Rare to find a forum where members pass up the easy opportunities to troll newbies. Very nice and patient people here.

So, the best advice I have ever seen for building a RMH is to start stacking loose bricks and see what happens. I stacked and learned how to build garbage, a actual RMH that was a fire extinguisher, and finally the real deal.

LESSONS LEARNED:
1: The proportions matter on lengths, area, sizing, cross section, etc. Don't try to reinvent the wheel. I tried. I failed.
2: If the ratios are off it can be the burn tunnel being shorter, there riser being larger and/or taller,  or the riser being farther from the barrel.
3:  Riser height! Riser height! Riser height!
4: Learn how to make cob. It is easy and a forgiving material if your location doesn't require good looks. For good looks, I need more practice lol.
5: There is a reason I could not find a perfect cob recipe. It is an on the job thing that goes by feel and the nature of your material. My clay, from posthole I had to dig, came with plenty of sand. Adding much more sand ruined it.
6: Start with a small project and don't expect it to go fast and easy.
7: Cob is heavy, messy, and sticky. Be prepared. Having a bucket of clean water around is handy.

Well, this was a learning experience. Not performing so well, as you could imagine. But now I do understand more of what I was reading. And in searching for answers to specific problems I have found much of the info I had been unable to locate before. Tearing it down and beginning anew tomorrow.

A rocket mass heater by an amateur. I researched this topic for weeks and the more research I did, the more my head was spinning. So I decided to start building something and see what happened. Keep in mind my limitations; no experience, no masonry skills, no money, zero on the money, know nothing about cob. That list of things I don't have or know could go on forever. What I do have is some salvaged bricks, mostly not good firebrick at all, a pile of scrap wood, some barrels, and a greenhouse to heat. I did some digging and started stacking loose brick.

Where I am at now is a fire breathing beast. I can't believe the heat. Now I need to get a barrel in it an exhaust. It is March 8th now and I only need this thing to last about 2 months. Then I can make something better.

Any quick suggestions now? I am so excited about this heat so far that I had to post something. Hopefully I can figure out how to post a video of it going. My 48 second video is too large so I am posting a link to it.

https://photos.app.goo.gl/SBd0iiQSTqh7II653