Cob Oven Build

[marklewis]

Started a cob/clay oven build a few weeks back. I am planning to build a fire-brick oven but thought I could learn a lot from first building a practice clay oven to learn from. (am learning much; this has been great for learning and looking forward to my first fire and first pizza and first bread, etc, etc!)

The oven is 27 inch inside diameter. The cob is 3" thick and will later be covered with 3 or 4 inches of insulation. The hearth is firebrick over a 2.5 inch insulated vermiculite/concrete mix. Cob is 1 part clay, 1 part red sand, 1 part fine sand, 1/2 part course sand mix, and just a little shredded wheat straw.

We made 3" wet bricks with a form and built the oven over packed sand one ring/brick at a time.

I cut the door today: 13.5" at base and 9.5" tall (inside dome is 15"). Will have more pictures soon of completed oven with cut door and sand removed)

Allowing clay to dry a few days before we pull out the sand form and clean up the inside. It's been fun but a lot of work.

[marklewis]

Re: Cob Oven Build

Here are a few more pictures. It is hard to wait for it to dry but I must be patient; would hate for the whole thing to collapse because I am impatient!

[Tscarborough]

Re: Cob Oven Build

Outstanding! I want to build one like that for fun.

[marklewis]

Re: Cob Oven Build

Nice Oven Tscarborough! Did you plan to remodel the house side to match your oven or was the oven an afterthought? Looks good!

It is fun to build and work with clay/mud; I'm already thinking of building a small cob study and/or sauna; but alas, must first finish the other 99 projects I've started!

[Archena]

Re: Cob Oven Build

Coolness!

Um, 'cob' and 'sauna' are two words that probably don't go together. Cob can't handle constant wetness and humidity that high that long would probably do not nice things. Cob will make a wonderful study though - and you can put the money saved toward the wood for the sauna!

[marklewis]

Re: Cob Oven Build

Coolness!

Um, 'cob' and 'sauna' are two words that probably don't go together. Cob can't handle constant wetness and humidity that high that long would probably do not nice things. Cob will make a wonderful study though - and you can put the money saved toward the wood for the sauna!

Your right, but I was going to make a dry heat without the steam! Probably never get to it anyway; I still have my treehouse and house addition to complete!

[Archena]

Re: Cob Oven Build

Well, yeah, if you cheat and be all practical and stuff!


Okay, so 'dry heat' and 'sauna' are a concept problem for me. :blush:

[marklewis]

Re: Cob Oven Build

I have pulled out the sand and newspaper. Totally cool!!! Will allow to dry a few days and then build a small fire to complete the drying process. My sourdough starter is almost ready!!! (dreaming of fresh hot baked bread!!!)

The oven is holding up nicely. It took 20 minutes to dig out the sand form and another 15 to pull off the paper but it held its shape well. The bricks worked well but I think one could build an oven quicker by just plastering the adobe onto the paper covered form.

Hopefully my next pictures (after several days) will be our first fire and subsequently some tasty pizza and bread.

[Archena]

Re: Cob Oven Build

Awesome!

Actually, using wet clay/straw/sand without drying it into bricks first is using cob. Adobe is when you make mud bricks first. (Yeah, I'm a definition nazi... )

But seriously, it looks great!

[marklewis]

Re: Cob Oven Build

Awesome!

Actually, using wet clay/straw/sand without drying it into bricks first is using cob. Adobe is when you make mud bricks first. (Yeah, I'm a definition nazi... )

But seriously, it looks great!

Reply from Mark Lewis: Thanks for the info: I'm bad about using the wrong term for something; learn something everyday! Thanks for the reply! Can you send me some pics or a link to your oven?

[Archena]

Re: Cob Oven Build

Unfortunately, I don't have an oven... yet. I still rent so I don't have anywhere to put one. I thought about a small scale but I honestly don't have time for it right now. Hopefully, I'll buy something reasonably soon, get moved in, find a way to fence in the Dogs of Destruction (loooong story) and then order a dump truck full of clay!

[marklewis]

Re: Cob Oven Build

Built the first small fire for drying and increased the size of the fire and dryed the oven completely. (It has been rainy here and I waited several days but the clay was drying so slowly and small cracks were developing anyway.) Cracks are inevitable!!!....and repairable!!! Fired without dome insulation until soot inside the dome burnt off and then we cooked our first pizzas, some bread rolls and baked some potatos.

The oven worked great, although the pizza peels I ordered have not arrived yet and using a piece of flimsy metal to pull out the pizza was challenging!

Am looking for good dough, and other recipes on the forum. If you have a tried and trued favorite please send me a link.

Repaired the cracks and am soon going to insulate the dome: will provide more pictures at that time. The inside is very stable but am considering applying sodium silicate to make the inside "glassy" and less prone to potential future spalling; so far so good though.

I could only very very briefly touch the outside of the dome once the oven was heated. It will be very interesting to see/feel the difference after the insulation is added.

[Archena]

Re: Cob Oven Build

Looks great! Congrats!

[jpmort]

Re: Cob Oven Build

Thats great and a real inspiration. I also want to build one now! If I could I think doing what you are doing is a really good way to experiment and learn and get knowledge about ovens. Then you can decide to do it better or different next time.

How are you going to stop thge oven from becoming affected by the rain?

John

[marklewis]

Re: Cob Oven Build

Thats great and a real inspiration. I also want to build one now! If I could I think doing what you are doing is a really good way to experiment and learn and get knowledge about ovens. Then you can decide to do it better or different next time.

How are you going to stop thge oven from becoming affected by the rain?

John

Hey John, I will render the outside for some protection but ultimatly I will build a simple tin roof or equivalent over the oven. At some point I will build a permanent pompeii and this one will become a novelty or as needed torn down if I need the yard space. Yes, I have learned much from building and using this oven and it has satiated my desire for wood fired pizza, etc. I'm thinking of making a permanent enclosed 36" incorporated into an outdoor kitchen with countertops etc.; but that will probably be a while as I am getting more busy with my seasonal service business of commercial refrigeration/air conditioning.

Thanks for the reply and best of luck to you and your endeavors; keep me posted of future projects.