Benjamin Dinkel

Dear Rocket Scientists,
a neighbor want's me to build an oven for her. Pretty much a copy of the one that I built.
I'm excited about it but I have a doubt.

My oven gets pretty black on the inside. I know, it's a black oven. But I was wondering whether that could be alleviated with a longer riser? It is a sign of incomplete combustion after all, correct?

In the current design the riser is 85cm (33"). I could get away with making it a bit higher at the cost of burying the core some 20cm (7").
Any thoughts?

Thank you Thomas!
If in 20 years I will have provided a sustainable heating solution to 20 homes I'll be content.
I'm grateful for all the work the scientists have put in and shared so freely.

I decided to put it there for ease of cleaning and in case needed to be able to prime the exhaust

Day 6 was all about plastering. I used a lime based plaster. The first layer has no fiber and is reinforced with a mesh.


Here you can see the mesh on the left side (core).


We also added some tiles





On day 7 I applied the second thin finish plaster with horse manure and lime.


Then it was time to wait.
After 1 week the first burn worked alright, some smoke backs. I was really worried. But it turns out it was just weird weather.

The owner now operates the RMH with proficiency and after it was fully dried, she applied a coat of silicate paint.
Here is the end result:



and some details:

On day 5 we closed the stratification bench and added mass on top in form of bricks bedded in very liquid clay mortar.


The top of the core was also closed with marble, we had more than enough and the material was free.


We then brushed a 1:1 mix of sand and NHL (natural hydraulic lime) on all of the surfaces to make a good connection and base for the plaster. It's like a thick paint, called "jabelga" in Spanish.


After everything was coated it was time for the test burn.


he rocket sprang to life and we couldn't identify any smoke outside. Success!

Thank you T for your inspirational post.
I too am baffled about how helpless a lot of modern humans are when it comes to dealing with their byproducts.
I lent my handbook to two different people already and everyone visiting our house gets a prep talk.
One by one we might make a change.

Hey Coydon,
yes, it's confusing. In Spain and Germany we count differently, the first floor is your second floor.

I don't know when they "upgraded" to concrete floors. Probably around the 70s. The new owner had to put steel beams under the "old" concrete floor.

Hey Jackson. The problem here was that we’re not in a first floor, but a second floor of an old house. It was reinforced not long ago. So the owner was obviously concerned about weight and had it checked.
Of course the people with the calculations stick to the safe side of life. But they also have the responsibility of something goes wrong.

Day 4 was probably my favorite day.

We raised all the brick walls to their finished height and solved a bunch of tricky situations with cob and brick cuts.





The exhaust path is closed off with a marble slab. On the bottom right you can see the bypass installed just after the manifold leads into the stratification chamber / bench.


Manifold installed and cobbed into place


Then the whole space around the core was filled with expanded clay and the top barrel put in place.



Baffle and bypass both in place and sealed with super wool


The first of the marble slabs covering the bench


Almost ready for the first burn

Hey Coydon,
I don't understand what you're asking or saying.
I used a similar product. It's like little balls of cereal, but made of clay.