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New Pizza Mud Oven build. A few pics.

Post in 'DIY and General non-hearth advice' started by fishingpol, May 22, 2012.

  1. fishingpol

    fishingpol Minister of Fire

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    This project has been stewing around in my head for several years. One stumbling block was where to get clay to build it. A few weeks ago a discussion came up here about something and I had the opportunity to acquire a few hundred pounds of clay from the king pyronut himself, Adios Pantalones. Thanks to him for the contribution.

    I decided on a mud oven because of three reasons in no particular order: short on time, space and money for a large oven. I did look at the ones built here from other members, and nice jobs too all. I just needed a decent size oven that could hold a few pizzas, or cook meat pies and lasagna type casseroles. This list will go on for what will be cooked in it. I borrowed a book from the library called "Build your own earth oven" by Kiko Denzer. That is the basis of the design and used his ratios for the dome and door.

    I'll get right into the pics.

    The stone base was built on a rebar-reinforced pad that sits on crushed stone. I dug down to the packed sand/shale rock layer as the starting point. I used a half pallet of Pa. fieldstone to build the cylinder base. I made a wood swing jig that sat on a piece of rebar, that allowed me to set the stone and spin the jig to get it to the edge for a proper shape.

    DSC01101.JPG


    The blocks were built up and the stone after that. The stones are set in mortar, and cured, then backfilled with concrete. The stone went up to about 30" the concrete about 26". The blocks were filled in also and topped with a thin layer of concrete to make it flat for the insulation layer. I mixed perlite and clay and made a 3-4" layer of insulation to slow/prevent the movement of heat into the base. I topped that with wet mason's sand just to the top of the stone layer. I used perlite/clay mix to form a ring to prevent the sand from spilling out of the circle.

    DSC01120.JPG

    The firebricks were set dry laid next, took two tries to get them flat.

    DSC01127.JPG

    I built up a sand dome of wetted mason's sand. I have a piece of 3" pvc pipe going to the center of the oven chamber covered with bricks to promote air circulation. I stuck a 12 volt dc fan to a solar panel to move air through the dome to try to even the drying out. I made a wooden arch for cut on a 5 degree angle so the final wood door will tip back and rest against the arch on its' own. The sand dome when completed was covered in newspaper to keep the sand/clay mix from sticking to it. All the sand in this pics was removed when the dome set. I cheated and used small stones I had laying around to fill in so I didn't have to buy more sand. It still used 150 lbs of sand. DSC01134.JPG

    Sand and clay layer went on next, then the cob layer of sand/clay/straw for insulation. I finished it off with sand/clay mix. Around the arch I set beach stones that the kids found. I put so much thought into the design and construction of this, that I did not think of the outside layer and what
    designs should go into it. The inner dome is 24" with a 12" wide door. I know it is narrow, but too much heat can be lost, and there are ratios to go by on dome heights and diameters.

    DSC01147.JPG DSC01161.JPG

    Here is the finished picture. I am building a roof over it now with probably a limestone shelf to set the baked goods on when they come out. I did a small initial firing to help dry it out, but the firebricks were saturated and the fire smouldered. The walkway is re-purposed concrete from a walkway that I replaced. I have enough flat stone left over to replace it if it crumbles this winter.

    I'll have more pics up in a few weeks when I really fire this thing up. I'll be happy to answer anyone questions too.

    DSC01159.JPG
    zap, Lewiston, raybonz and 3 others like this.

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  2. Eatonpcat

    Eatonpcat Minister of Fire

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    Very COOL!

    Can't wait to see it cooking!:cool:
    ScotO and DexterDay like this.
  3. smoke show

    smoke show Guest

    Cool project.

    Good job.
    DexterDay likes this.
  4. Adios Pantalones

    Adios Pantalones Minister of Fire

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    What a great job!Now the questions

    So how much clay total did it take?
    How thick was the inner adobe /outer cob dome?
    Have you had to evacuate any hippie drum circles yet?

    edit- how long do you think this took in hours (soup to nuts)? If I had the materials on site, how many weekends working long days might it take?
    DexterDay likes this.
  5. Jags

    Jags Moderate Moderator Staff Member

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    I'm hungry for a slice of pie.

    Nice job on the oven.
  6. jeff_t

    jeff_t Minister of Fire

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  7. fishingpol

    fishingpol Minister of Fire

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    Thanks all, it was tough work for sure. A lot of material hauling, stones, 80 lb bags of mortar and concrete, sand. Pure grunt work. This is something I hope to use all year round.

    Ok AP here are the answers, with many variables:

    1.) 150 lbs of clay, 2 to 1 ratio on the sand, so 300 lbs of washed masons sand. It was nice as the clay slugs are 25 lbs and a bag of sand was 50 lbs. Easy measuring, no guessing, one of each.

    2.) 3 layers, first sand/clay about 1 1/2" thick, second sand, clay and straw about 3", last sand/clay layer just over an inch. Total of all 3 layers is 5". From what I read, the layers can vary. The thicker the cob layer, the more insulation to retain the heat.

    3.) No evicting the hippies yet. Many a free beer was brought down by the neighbor. I do feel the need to make a colonial clay pipe now to smoke when the food cooks.

    4.) Timewise varies. If using larger stones than what I used, maybe a full weekend. I built up about a foot of stone at a time in a circle all mortared. The next morning, poured concrete behind it to the blocks. I had to let the mortar cure, before pouring concrete. My time was chopped up working here and there. Probably 12 hours total for the base. About the same for the perlite/clay, firebricks and dome.

    I found that you can make up the sand/clay mix all at once and let it set for a day as it will firm up a little and be a bit stiffer to work with. Mixing the sand/clay is a PITA. I only needed a few handfuls of straw for the cob. Too soupy of a mix will cause drooping off the dome. I have a ton of other tips.

    Watch this video, as he covers it very well. Probably the best one I found, and I did a lot of searching.


    ScotO and Eatonpcat like this.
  8. potlatch

    potlatch New Member

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    Nice oven! I like the doorway detail. In my experience, the optimal thickness for most home ovens is about 3" -- rough rule of thumb is an hour of fire per inch of mass, tho a 3" oven can often be used for a short bake after an hour (it will cool down fast). The more insulation the better, but mass does not equal insulation -- that is, more sand and clay, even w/straw in, will suck heat out of the oven. (good illustration of this at http://www.fornobravo.com/pizza_oven_selection/thermal_mass.html) To work well, insulation has to be lightweight, not dense. Best is to insulate under the floor (bottles encased in insulation -- ash, perlite, sawdust/clay mix), and insulate all around the dome. For a cheap DIY solution, I like sawdust mixed with clay slip. Mix clay w/water until it's a bit thicker than heavy cream; then add sawdust until you get a workable "dough" -- pack it around the dome 3-6 inches thick, or more. It takes a long time to dry, but it's cheap and good. Gets better every time you fire the oven since the sawdust cokes out leaving nothing but lightweight clay foam. May your firewood be old and dry! -- Kiko Denzer (handprintpress.com)
  9. DexterDay

    DexterDay Guest

    Very nice oven....... Thanks for the pics..

    Now on to the new guy?!?!?! !!
    Wow.... 1st post... Lots of info

    Welcome to the Forums... Any Pics. This is assuming that you have one hell of an oven? ;)
  10. fishingpol

    fishingpol Minister of Fire

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    Thank you for the kudos. Potlatch, are you Kiko? It is truly an honor that you took the time to recognize this oven. I tried to glean as much information from so many sources on the net and everyone mentions the book as the "go to" reference. I basically went with what many blogs and videos were using as a happy medium. That link from fornobravo is great also. I probably should have added more straw to the second layer, but I went with more sand/clay for strength. I am crossing my fingers for a good first run.

    I had about 20 beer bottles for the insulation layer ready to go, but they did not lay in an even "sunburst" pattern. I was concerend that there would be uneven spots all over. The perlite was mixed with just enough water/clay to hold it together and tamped down. I have a few inches of that layer. I was thinking of a micore layer, but I was trying to cut costs here and there. I will be cooking mostly a few pizzas at a time, so a short heat cycle should suffice.

    Dry seasoned wood- check.
  11. ScotO

    ScotO Guest

    This is AWESOME! You did a great job, and you documented the project very well. I WILL MOST DEFINATELY have a stone pizza oven someday. I had planned on building one this year, but with all the work I have to do to finish my living room and fireplace install, plus all the tree work I do on the side, it's gonna have to wait another year. I want some pics of your pizzas, FP! They are easy to make and are absolutely FABULOUS. My mouth is watering as I write this post. Again, fantastic job!
  12. fishingpol

    fishingpol Minister of Fire

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    Thanks Scott. I'm liking your firepit pics too. I've been thinking of this oven for several years. I am hoping that in 2 weeks, after a good dry out, this oven will be belching pizzas. Barbecue chicken with onion, and sausage pizzas are on the short list. There will be pics in the nook when it happens.
    ScotO likes this.
  13. ScotO

    ScotO Guest

    Looking forward to seeing the pics of the food!
  14. bfunk13

    bfunk13 Minister of Fire

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    I am seriously jealous! I am a home pizza maker and have nice results with a pizza stone, a good home made dough and sauce recipe.
    I have been researching the backyard brick oven and will have one someday. I love neapolitan style, but without a brick oven and high temps i settle with American style. Be sure to post some pizza pics. Here is a recent pie.

    DSC06656.JPG
    Eatonpcat and ScotO like this.
  15. fishingpol

    fishingpol Minister of Fire

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    That looks real good bfunk. I do remember your pizza posts a while back, those were fine looking pies. I'll be sure to post some up. Get your bibs ready.
    Eatonpcat likes this.
  16. potlatch

    potlatch New Member

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    I think the pattern of bottles doesn't make too much difference, so long as there's something under each floor brick, and so long as the oven walls have support. I think of the bottles as similar to the pilings they put under big buildings -- it's a network of connection to support the weight above; the bricks span the gaps and spread the load. I'm wondering if the edition of Build Your Own Earth Oven that you got from the library was the old one? The new edition (3d) covers the insulation in greater detail. Insulating makes such a big difference (which is partly why I try to follow up when Google alerts me to various posts - it's so easy to burn lots of wood when you have a lot, and so hard - and slow - to grow a forest - much less the soil that feeds us all). I've also been using cardboard to make a thermal break between the thermal layer and the insulation layer, which is standard practice in masonry heaters, but I need to get that up on the website (http://www.handprintpress.com). We're trying to get more info up and to make it more useful. My colleagues Max and Eva Edleson are also about to publish a new book on making a wood-fired oven from a 55-gallon barrel wrapped in mud/brick - heat up time is only 20 minutes! happy heating and baking! -- Kiko Denzer
  17. Adios Pantalones

    Adios Pantalones Minister of Fire

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    Good info. I'll be using insulating fire bricks (IFB's) as insulation, because I have a couple hundred spares
  18. potlatch

    potlatch New Member

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    thanks for the welcome. My own oven is actually thicker than I'd like, and a bit under-insulated (it must be almost 10 years old by now!), but it holds heat well enough to bake 25 pounds of dough (in two batches) and enough food for days, as well as heat for tempering tools, dry the next load of wood, etc. (one day, heating water!) I am hoping to rebuild thinner and better insulated -- maybe this summer. As for pix, I'm afraid I have to refer you to http://www.handprintpress.com/kiko. My life took a turn towards (earth) ovens about 15 years ago and (I suspect like many others in this wired age) I've combined the arts that keep my family in bread and butter and made them public on a website. So -- full disclosure -- it also represents a (very small) business that tries to encourage and provide info/inspiration for learning by doing. Clean, efficient, DIY fire and heat are a big focus, for reasons well stated here, in a favorite quote:

    "According to Alfred Faber [a German historian of heating technology], the great innovations in stove design during [the period in which masonry heaters were developed] seldom came from specialists in the field.... 'Homeowners,' Faber found, 'often experimented for years on their own stoves to reduce wood consumption. Their discoveries have appeared in hundreds of reports, books and journals. Among them almost all profession are represented: government officials, priests, monks, doctors, pharmacists, mathematicians, professors of all fields, but also painters, architects, merchants, manufacturers, diplomats, military men..." [from Alfred Faber, 1000 Jahre Werdegang von Herd und Ofen, Abhandlungen und Berichte, Vol. 18 Deutsches Museum, Munich, 1950.]
    "It is curious, and perhaps not just a coincidence, that the first patent for a wood-conserving stove came in 1557, just seven years after the beginning of the Little Ice age....

    -- from David Lyle's Book of Masonry Stoves
  19. raybonz

    raybonz Minister of Fire

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    Wow Jon you did a great job on that oven! I would love to build one in my yard too.. Even looks great just sitting there doing nothing!

    Ray
  20. fishingpol

    fishingpol Minister of Fire

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    Thanks Ray. It was a lot of work, but well worth it. I see many pizza nights this summer with the neighbors. There are a few others here starting the process of building one. Once the roof is done, I'll put up a final picture.
  21. ironpony

    ironpony Minister of Fire

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    after looking at this process I am reconsidering my thoughts about my building process.
    have the foundation in, just need to look into this method further and decide which way to go.
    seems this way might be more cost effective, and a little easier than laying up a brick dome.
    looking into castable refractory, luckily I have a local company I have worked with on some furnace repair
    at a aluminium forging plant. thought about using castable refractory for the dome part so it is pretty and then insulating
    and concrete on top of that. more research to do.
    Want to have a 42-48 inch dome, thought about starting with an igloo dog house for the mold to cast the refractory......
  22. Jags

    Jags Moderate Moderator Staff Member

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    Hmmm...just thinking outloud...Do you mud slingers think this process would work in reverse to make something like the "Big Green Egg" or Kamado cooker??
  23. Adios Pantalones

    Adios Pantalones Minister of Fire

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    Jags- my design will now have an offset firebox which could be used as a smoker. The large mass of clay will retain heat and even it out, I suspect, for longer BBQ cycles.

    You can cast parts from refractory cement, or adobe, or use a combo of brick and refractory/cob- just don't try to make the domes too short, as bracing would be required to keep the walls from pushing out.

    My design will be based on a noborigama (climbing-kiln). The shorter dome at the left is the firebox- then I will have one chamber for cooking (smaller, obviously). There's no reason you couldn't do a freestanding catenary arch chamber with simple removable racks for smoking.

    [​IMG]

    These can be quite large

    [​IMG]
  24. Jags

    Jags Moderate Moderator Staff Member

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    That is pretty darn cool. I am looking for something a bit smaller in stature. Something like the "Big" big green egg. More of a grill than a smoker, but something that can be held low and slow if I want.
  25. Adios Pantalones

    Adios Pantalones Minister of Fire

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    Well, mine won't exactly be "walk in", but there's no reason you couldn't.

    Just put a couple bricks in each side on the hearth and toss a grill on there. You can make a door from plate steel backed with kaowool or M board. A chimney with a damper is easy peasey Portuguesey for controlling air flow- you just need a couple slots/tuubes in the floor I can show you how to do that really easily as well) to feed air.

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