RMH completed - some fotos and big thanks!

Three years ago I started to plan my Rocket Mass Heater project and I posted a lot of questions and thoughts here: https://permies.com/t/40/210656/Questions-building-tube-RMH-tiny

The Heater worked since october/november 2023 but was just roughly finished. In the last weeks I finally did the last finishing work (fine plaster and a layer of lineseed oil varnish).

With this post I want to share some pictures and say big thanks to all of the wonderful people in this forum who helped me and who help others! Who share their knowledge without expecting anything in return. Spaces like this where people work together because they share similiar ideas or values are so important from my point of view. So: THANKS A LOT!

And I want to encourage anyone thinking about building a Rocket Mass Heater to just go ahead and do it. My tiny house has become so much more comfortable thanks to this change.

I'm also open to share more details about difficulties, experiences and how I realized different steps of this build although I'm not online in this forum that often.

Superb Job, Jonas!
That is beautiful, thank you for sharing it with us!
Information about RMHs has always been freely shared, and builders like you help to spread the warmth around the world!
Keep up the good work, and help others build their own RMH.
Talk to random strangers about RMHs and spark interest for another new builder.

You decided to drop the bypass? [edit: I guess it is that handle coming out of the cob- forgot this was a 1.5 barrel high radiant chamber.]

That is a gorgeous RMH. I think it deserves to be in the list of beautiful rocket mass heaters.

I totally agree with Harold.
What a beauty!
What is the plaster colored with? What type of plaster is it?

Also, what did you use to get the barrel so nice and black?

Thank you for your kind and encouraging words!

@Coydon: Yes, the bypass is connected to the bottom barrel at the very top. This allows me to completely remove the top barrel when cleaning the heater. The riser extends only about 12 inches into the top barrel. The draft with the bypass open is sufficient for my needs. Only if the stove hasn't been lit for a while I need to light some newspaper in the burn Tunnel when starting the heater to prevent smoke back.

@Benjamin: For the core of the heater, I used a yellow-brown clay. For the finish coat, I came across a really beautiful reddish-brown clay. Both are from local soil in friends’ gardens. We generally have rather clay rich soils here. The fine plaster consists of 1 part red clay mixed with 4.5 parts fine sand, coated with linseed oil varnish. The barrel is painted with linseed oil varnish mixed with soot as a black pigment. I found the soot as a fine powder while cleaning the inside wall of the barrel and then read that black pigment sold as "carbon black" should be more or less the same product. So I tried it and it worked. When the oil is burned into the metal, it produces smoke and smells like burnt oil—so it’s better to do this outdoors over a campfire. Once it’s been burned in, however, it no longer smells and won’t stain. I did this procedure twice - first time without pigment, second time with the pigment.

This is gorgeous! I was looking back at your original thread and saw how much higher the bell goes than the top of your rocket stove. I thought you just needed a couple of inches to keep air flow, does this change performance? Or does it just give more radiation area? Sorry for my ignorance!

Hi Zac;
Good question.
In the early days of RMH development, heat from the riser moved down a metal pipe buried in a solid cob mass.
It was deemed necessary to have a tight area above the riser to help "push" the heat down into a transition area, and then through up to 50 linear feet of pipe.
With the development of stronger RMH cores (batchboxes) and the use of stratification chambers  (bells), it is now common practice to leave 12" to several feet of open space above the riser with excellent results.

Ah! This makes a lot of sense, thank you!