dmun's 36" geodesic oven

[dmun]

closing for the winter

Here's a view of the framework of the temporary roof I built out of used lumber:



This got covered by some used plywood and a couple of layers of tar paper.



This just sits on top of my structure. There is a bag of used insulation stuffed in the future flue opening in the front of the oven.



Not much to look at, but it will keep some wind and wet out of the structure until the end of winter.

I'm thinking that this is a good stopping point, and I'll start a new thread in "design styles, chimneys and finish" when work resumes, and leave the pompeii section to people who are in the oven building stage of their projects.

[edschmidt]

Re: dmun's 36" geodesic oven

I hope people are still checking in. I just joined this forum after being on the yahoo brick group for 1 year. Anyway I am a kindered spirit on the geodesic oven design. I designed mine on the computer about a year ago and started casting the triangles out of 2300deg. castable refractory. My mindset was that large castable refractory ovens crack, so if I cast the smaller 4" thick triangle and not mortar them together that they could expand and contract with the heating cycle without cracking. I assembled the triangles, added a building paper slip layer (Im sure burned out long ago. The entire dome I then covered with 4" of reinforced concrete. I have been firing it at least weekly since april with absolutely no cracking and 12 hours after the fire is removed the oven is still in the 270-300deg. range. The entire oven including base, vermiculite and roof so far has cost me $500.I will try to post some construction photo's if I can figure out how.

[Amishcountry]

Re: dmun's 36" geodesic oven

Ed, Please, Please, Please.....give us more info on your oven.

I am planning a garden and pizza oven for a spring summer project. I have been tossing the pro's and con's of various oven designs back and forth.

"Dmun's" g-dome has intrigued me, but I doubt I could do all the brick cutting, as he is truly a skilled artisan. Dmun's project is truly a benchmark for inspiration.

Through research, I have found various threads stating pro's and con's about trying to cast your own oven parts.

However, none have mentioned casting small parts(the triangles), as you have successfully done, with your G-dome. Sounds like you have come up with a winner!

Can you share more about the casting mix you used for the parts, and any specifics, plans, measurements etc....for the mold to make the triangles.

Thanx for sharing, I'm sure your post will generate a tremendous amount of interest.

Do you have website, blog etc...for more info??

[edschmidt]

Re: dmun's 36" geodesic oven

I dont have a blog, or website, but I did take a decent amount of pics during the constructions phase. Did the pics that I posted come through? I cant view them on my computer. Anyway I could not find Aluminum silicate cement where Here in Grand Rapids MI (but wasnt sure where to look) So I looked on e-bay and found a company which sells pre-mix castable refractory, and the company happened to be 15 min. from my house. It was designed to be used for melting metal so its obviously plenty overkill, but I prefer that (I also got the firebricks for the hearth from them which are super heavyduty(2600 deg.). Anyway It took 10 bags of castable at $20 each (50#bags) to cast the 4" thick dome. Including the outside layer of thermal mass I have 8" of Mass in the dome. For the hearth I poured the concrete slab over my blockwork with a slip layer (aluminum to seperate slab from blocks) then 4" of vermic/cement mix, 2" of sand(for additional mass) and laid the firebricks on top of that. I know that most people use the slab as part of the thermal mass, but because I was not interested in suspending the slab, And I didnt the heat to weaken the slab which is responsible for holding the entire oven up, I decided to put the thermal break between the hearth and the structual cement Plus sand is cheap and an effective thermal mass.
I think Im getting a little long winded, Let me know if the pics came through, if not I will re-post. P.S. where are you located?
Sincerely
Eddie Schmidt

[edschmidt]

Re: dmun's 36" geodesic oven

A couple more things I thought I would point out, Im not sure if dmun square cut or angle cut the bricks(from outside of oven to inside of oven) but the triangles that I cast were larger on the outside of the dome than the inside which is how I eliminated the need for mortar, and allowed the dome to be selfsupporting without it. In the geodesic pic. you might notice the newspaper holding the dome up. What I did is take my sons large 48" inflatable kick ball and inflate it to 36", cover it with about 10 layers of paper mache' and use that as the temporary form to hold up the oven. The oven becomes self supporting once the final brick is put in. I then just pulled the form out through the oven door.
Eddie Schmidt

[jengineer]

Re: dmun's 36" geodesic oven

yes we can see the 3 pics that you posted - keep them coming

[james]

Re: dmun's 36" geodesic oven

Ed,
This is a quick response -- with more to come later. I just wanted to say what a great-looking oven you have built, and that we are pleased to have you in our group. Nice idea for the form; as the Brits would say, well done, or in Italian complimenti.

Would you be happy to start a new thread under Pompeii Oven construction? I think people would enjoy hearing more about your construction, and this thread is already pretty long and full of information.

Also, please feel free to post as many photos as you have in the Photo Gallery.

Welcome aboard.
James

[redbricknick]

Re: dmun's 36" geodesic oven

Who do you think would win in a no holds barred cage fight between Dmun and Ed? Both of you guys live on a plane of expertise upon which I can only cast covetous glances.

[dmun]

Re: The Ed Schimidt geodesic oven

Hey this is great: It looks like your elements fit together better than mine did because they came out of standardized moulds. Yes, my triangles all had a seven and a half degree angle on the sides, and it seemed like the right fit.

Now if only we could get someone with connections in the refractory industry (hint, hint) to get the two styles of tapered triangle bricks cast that you need for this project. I really like the brick look.

Did you really assemble without mortar? That's WAY impressive. Mine would have fallen into a heap without refractory mortar. Keep the pictures coming: We would like to see your door and vent details.

Your project looks really good.

[edschmidt]

Re: dmun's 36" geodesic oven

You know I do have a kiln, I could fill my molds with earthware clay which is fired to cone 8-10 2000-2300 deg. and has a high shock resistance. It obviously can tolerate high temps, and costs approx. 34 cents per pound. The triangles would easily fit into the kiln and the density is comparable with firebrick. Can you see any downsides?

[edschmidt]

Re: dmun's 36" geodesic oven

P.S. Depending on the clay used it would be between bright white all the way to deep red in color and many colors in between. I could also put a pattern into the mold to give it a brick look( or smiley faces,pizzas etc). The only thing I am thinking is that clay shrinks between 10-20 percent when drying so my molds would have to be made larger in order to keep the 36" inner chamber. Thoughts?

[james]

Re: dmun's 36" geodesic oven

Nick,
Are you having one of those "Mongo is just a pawn in the big game of life" moments? I am really enjoying seeing all of this fly by. Ed and David, keep going.
James

[redbricknick]

Re: dmun's 36" geodesic oven

DMUN. The way you cut and reassembled your flue tiles.. How heavy would you estimate the whole rig to be including the eight inch piece on top.. How strong are the joins? I'm trying to figure a way to support the weight of my flue from above, as my vent will be suspended.. I haven't been able to find flue tile in any significant length.. The only similar clay tube is a terracotta sewer pipe, and I doubt it's ability to withstand high heat.

[need2retire]

Re: dmun's 36" geodesic oven

Can't you just cut the standard square/rectangular fire brick
into a wedge shape to build a dome? This way there's no need to cut or precast a triangle piece. Seems to me putting together a dome using square/rectantular pieces is more error tollerent (deviations in measurement and motar thickness).

[stuart]

Re: dmun's 36" geodesic oven

I don't know how I missed this thread for so long, but my lord what amazing work! I sat down this morning with my coffee to do quick bit of research for my project and stumbled across this. Read the whole thing start to finish and now my wife is worried we'll be late for Easter brunch at her sisters! LOL Thanks for sharing, I am humbled.