Benjamin Dinkel

Hey Gerry,
mine works with just a roof tile on top, so I think there should be enough room for the exhaust to escape.

And as for the roof, it will be metal. I was thinking going through the roof, but that makes it much more complicated. With my tove the tree branch right above seems to be fine, it's not really hit exhaust. So I'm assuming the wood structure will be fine.

But of course we'll have an eye on it the first burns.

Because of the rain and the arch collapse we decided to continue building a roof:




And when the weather became better I redid the brick vault.





When taking the support out I was nervous, but this time it worked. And I decided to do the back of the oven with the chimney first.





The chimney is a regular pipe but coated in cob and with a traditional "hat".





Took out the front support and everything seemed stable.




So I closed the front of the oven.




Now I'll have to wait for a week without rain and apply 2 layers of lime and clay plaster to finish everything up.

Thanks Phil, Scott and Thomas.
I'll keep your comments and ideas in mind for the next one.
The thrust line is a helpful concept.
I was thinking of trying one with the bricks laying down. But it would make the base even bigger if I want to maintain the oven size.

Yeah, it was a couple of hours of unpaid labor in the end. Cleaning up and rebuilidng I obviously didn't charge.
But it was cool to be able to reuse the material, just soak and repeat.

My builder friend mentioned he thought the arch was very wide. It's basically a half circle. Do any of you have had bad experience with half circle brick arches?

Hey Lara,
can you specify what you mean by "on the ground"?

You want to build a rocket mass heater and use your floor as the mass? And you want to build the ducts from stone?

Lara Curtis,
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With the base ready I could start with the actual oven part. In the next photo you can see where the top of the riser ends under the future pizza stone and distrubutes the heat in the bottom of the oven.




The clients also wanted a kitchen counter next to the oven, something I'm missing with my oven.






At the same time I was building the brick cuppula.




And then the weather changed. It was raining all the time. So the day I wanted to continue with the front of the oven the cob and insulation (shiv and clay) wasn't really done yet.




Thankfully the counter wasn't damaged. I cleaned up, separated the materials and decided to wait for better weather.

My neighbors hired me tobuild them an oven after being invited to a Pizza party with my Cob and Brick Rocket Oven.
The basic design is very similar.
6" J-tube from dense fire brick heating up a brick and cob oven structure.
The client insisted on an ash clean out, the first new innovation compared to the previous model.




The base is river rock and lime mortar. Insulated against the ground with ~4" of expanded clay.



The dense fire brick is held together mostly by gravity with the aid of a bit of clay slip.





The whole core is then wrapped in RockWool.



To save on time I decided to use bricks to build up the body around the core. The interior spaces are then filled with expanded clay for insulation.



In the next photo the ash cleanout can be seen in the bottom of the feed tube and also the tile that keeps the top of the feed tube protected.



Kalu wanted to "help" by digging in the cob mix and also by biting into my tools and tearing up any plastic she could find. At the end of the workday everything had to be made dog proof. And she had to be chained to a tree most of the time unfortunately.





The base for the oven is complete

Hey Tycer,
while I can understand that you feel rushed, projects and budgets usually benefit from thorough planning and decision making.
Before you get the materials you need to decide on which type of rocket you want to build. And that mainly depends on your needs.
If you provide more info, we’re all here to help you.

Hey Erinanne,
you want to turn your old wood stove into a rocket mass heater?
I’m sorry, but I don’t see a lot of good that can come from that. The stove was not designed for complete combustion, so you will have creosote problems if you cook your exhaust gas down too much.
Also “upgrading” it with mass or cob is not that easy.
There are cheap and easy ways to build reliable rockets. There’s a lot of resources and people willing to help here on permies in case you decide you want to build one.