Andalusian Pizza Rocket

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

Sweet Pizza oven, Ben!
Keep up the good work!

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.

Ahhh   what a bummer.
It's just clay sand and bricks, and it will clean up and be reinstalled... but how sad to walk up and see it collapsed!
Chin up, rocket scientist, and carry on!

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 Ben
This is how Gerry and I built the arch on Shorty.

Benjamin Dinkel wrote: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. . Do any of you have had bad experience with half circle brick arches?

By having such a small compressive face ( the bricks laid flat in your arch ) you are pushing the limits of your thrust line.  The thrust line, is simply from the center of the top of your arch to each outside edge of the arch.  The thinner of the face, the harder it is for this line to stay within the top and bottom of the brick faces or perhaps better said, inside and outside of the arch. Viewing from the end, this line should always be within the inner and outer faces of your brick.

I suppose with the cob hard this would greatly help, but until hard, there would not be much compressive strength at all.

But as you say, only some time has been lost.

Ironically I had a very simple arch collapse today, but was do to my  not holding the above mentioned thrust line stable at the base--  Totally my fault.

thomas rubino wrote:Hey Ben
This is how Gerry and I built the arch on Shorty.

Is that a catenary, Thomas?

Good line, Tom

You know Phil.
I stated that Gerry and I built that arch.
The truth is, Gerry did all the math, and I just screwed it together.
I believe the height was determined by our vertical (soldier) bricks.

I wondered because it sure looks like one. If you still have the template, you can put a nail at either end and see if a length of rope hanging from them follows that curve. It's an ideal form for arches and domes, and so easy to generate with a piece of string.

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.

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.

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

Great job Benjamin!
The only thing that looks questionable is the "hat".
From the picture, it appears that it may cause too much dampening of the draft.
I guess time will tell when you light it up. An easy enough fix to enlarge the pillar openings if needed.
Also, wondering how close the hat is to the future roof. Hope your client is not insisting on a straw roof!
Could it extend through the roof instead?
Keep up the great work.