Cob Oven Build

[Archena]

Re: Cob Oven Build

Interesting! Thanks, Mark!

[marklewis]

Re: Cob Oven Build

I still use the oven occasionally. No I never finished the outside. I did a test area with a perlite mix and concrete over part of the dome (few inches thick) and you can hold your hand on that area but not on the clay dome when it is fired to temperature.

[marklewis]

Re: Cob Oven Build

Hey, the oven is holding up well considering it is outside with only a flimsy tarp over the structure. I still want to build a bigger one and more permanent but alas I have since followed other projects: claypot tandori & later flying remote control planes and most recently getting my pilot's license and various endorsements in various planes (both nosewheel and taildraggers).

The oven still works well, I never insulated it completely and I still like to watch the fire roll around inside.....a larger dome would be more practical but it works for small pizzas.

[Mario Borja]

Re: Cob Oven Build

Mark, hi. I have been following your build. Nice job on the cob! I am going to build one soon and want to follow your form. Any more pics on it? How is it standing up?

[Wazza-Mick]

Re: Cob Oven Build

nice work I love the clay brick forming in the mold

[electricbill]

Re: Cob Oven Build

After 2 1/2 years, what is the rest of the story?

[aiannar974]

Re: Cob Oven Build

are you still using the cob oven. how has it held up? did you ever finish the outside?

[marklewis]

Re: Cob Oven Build

mn8tr: Amen!! no better stress relief than to get dirty!! I saw your build; looks nice. Did you design it or use some plans? I was wondering if your bricks in the dome are larger than most builds? The larger bricks would expedite building. Did you cut the dome bricks at angles to reduce the cement gap or just go with it? any problems after firing. It really looks good: I want to do permanent build with firebricks and I like your design: any drawings or schematics you could post, etc??

Separtely, the pool and hot tub are a nice addition to the oven!

Thanks, Mark Lewis

[mn8tr]

Re: Cob Oven Build

Nice work all around, that does look like a fun project to try. Little boys playing in the mud, some things never change.

[marklewis]

Re: Cob Oven Build

Thanks, It looked even better until the cracks formed! (as they will!)

[stephen*z]

Re: Cob Oven Build

Mark,
what a great job! my visionof cob ovens is mud piles with burn marks on them. yours looks like a piece of pottery. nice job.
Steve

[marklewis]

Re: Cob Oven Build

Hey Joe, Thanks for the reply. I drove some back roads and found a dark red spot where the road crew had dug through a hill. Clay is pretty common here in fayetteville NC. My mix was 1 part clay, 1 part sand mix from lowes and 1 part reddish sand 1.5 feet down in my back yard. I also purchased wheat straw from lowes and shred it by hand and added it to the mix.

There is a thread on here from a guy in hendersonville nc where he first made cob bricks and then built his oven. I think this will work well or you can do wet bricks like I did or probably just lay it on thick around a sand mold core & make sure there are no air gaps.

You may want to experiment first with a very small oven just to see how you like your mixture etc. Some even make a very small test one that you could bake a muffin in as a test.

Be prepared for cracks with a cob oven. eventually I will make a larger firebrick oven when I get time. Have fun!!!

[BackyardPermaculture]

Re: Cob Oven Build

I am going to try and do an eath/cob oven soon and am trying to figure out the best mix of clay/sand. Where did you get your clay from? Was it commercial or just out of the ground?
Joe

Joe, FWIW I'm also just completing a cob oven build. I used commercial "ball clay", which is a very fine powder. The mix was equal parts clay, sand, crusher dust, with some portland cement added. I think the amount of clay could have been reduced even further to reduce cracking, although the cracks haven't been too bad.

The essential thing is to add fibres (aka "fibers"). I used quite a bit of natural rope chopped up; traditionally straw is used. Either way, make sure you have something in there!

Also consider a design with a chimney situated outside of the door/opening.

Cheers,
Mick

[SloW8]

Re: Cob Oven Build

That thing looks great! Any update? New pics? I am going to try and do an earth/cob oven soon and am trying to figure out the best mix of clay/sand. Where did you get your clay from? Was it commercial or just out of the ground?

Joe

[marklewis]

Re: Cob Oven Build

Hi Mark

I just posted an answer to your question on my profile thingy...

Your oven looks great, really tidy looking mud oven! And the pizza looks yummy pizza too, congratulations! What are you going to use for insulation?

Hey Frances; Thanks for sending me a link to your oven pictures; your oven truely is work of art!
I'm going to use 4" of vermiculite/concrete mix over the dome for insulation. I used a 5 to 1 ratio under the hearth. I formed a test area of 3" on the dome and after 1 hour of full firing it was about 100 F. I think 4" will perform well for my needs and then a final layer of rendering for protection/cosmetic detail.