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Polystyrene vanes (dome modelling) - First message - Forno Bravo Forum: The Wood-Fired Oven Community


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Polystyrene vanes (dome modelling) - First message

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  • Polystyrene vanes (dome modelling) - First message


    As descripted on previous message, following some pictures of the Pompeii oven dome building.
    I hope this pictures could bring some help to new builders.
    By the way, since I am sending pictures by the very first time, I will send five ones in this message, only to see if I am doing right. If so, I?ll send more next.
    Nice to learn from this group.

  • #2

    I can't see your photos. You attachment them by clicking on the "manage attachments" button just below here.

    Pizza Ovens
    Outdoor Fireplaces


    • #3
      Pompeii oven - Polystyrene vanes


      I resize several of my pictures and I am sending five of it now.
      I expect this could be work.
      How I said, I have a lot of photos of my oven construction, slab-hearth-dome-door-vent-a lot of pizzas and so on...
      If this message works and you believe that my pictures could be of some help to someone, let?s know that I?ll send a lot.


      • #4

        Hello. I have been reading and in the progress to start my 42" oven, and like the Styrofoam pictures, like to see what else you have done. I just finished pouring A 30' X 22' X 4" slab with footings beneath the founcaton for a 15'L x 12'W BBq cement block for an outdoor kitchen that the oven frame and hearth is attached to the bbq walls. Pour the entire slab and oven hearth at one time, with 5-1/2" of concrete and rebar. I did not use heat insulation in the lower half of the slab. I live in SoCal and it does not get that cold, plus I intend to double up on the bottom bricks. In any case when I am done I will post the pictures from the very beginning of the project. I do like the pictures for the design of the dome, it makes perfect sence. I have a question regarding the flute, and that is from how far back from the opening of the oven does the the flute begin. I have seen some pictures but they have not been clear, on just how far back the flute is positioned.

        Thank you.



        • #5

          I have been wanting to see if I could help clariffy the terms we are using in the forum. I think for this group, we should use the term "foundation" for the concrete slab that sits on the ground, and "insulating hearth" (or "hearth") for the multi-layer hearth that rests on the the "stand" (typically made from concrete blocks). That might clear up any confusion on terms, and the difference between issues regarding the foundation and the hearth.

          The foundation's sole role is to support the oven, not sink into the earth or tilt, and not be pushed up by frost. It isn't thermal, doesn't impact oven performance, and has no insulation. The primary issues are the sized of the footprint (relative to the size of the oven), not being pushed up by frost, and perhaps ensuring that water doesn't pool under the oven (the foundation should slope slightly down to the front of the oven.

          The hearth is a different part of the oven, and should be insulated to keep heat inside the oven chamber. That is why the hearth has a layer of vermiculite insulating concrete -- which stops heat from escaping from the oven chamber.

          Hope this is useful.

          Pizza Ovens
          Outdoor Fireplaces


          • #6

            Great photos. They came through nicely on my computer. Thanks.

            Have you posted the dome height elsewhere on the forum? What are the dimensions and what did you use for material?

            Pizza Ovens
            Outdoor Fireplaces


            • #7
              i would have to agree with james about the importance of insulating your hearth beneath (and around if possible) the thermal layer which the floor bricks sit on. i have had problems getting my floor to heat up enough, even with the 2" of vermiculite concrete insulating the bottom of the hearth slab. i believe this is due to the enormous size of the thermal layer and the subsequent large amount of thermal mass to heat up.
              overdo it or don't do it at all!

              My 2005 pompeii build


              • #8
                Position of flue

                To address Fabio's question about the position of the flue, It should be as close to the oven as possible while still allowing the baking chamber to be completely sealed off with a, say, inch-and-a-half thick wooden door for baking.

                My geodesic oven project: part 1, part 2


                • #9
                  Dome measures and vent pictures.


                  Yes, I had posted the details of the oven in the Messages section, including a description of the polystyrene and cardboard work that I believe could be useful.
                  I would like to said that the dome model with 3/4? polystyrene sheet mounted as showed in the pictures is really strong. Because I shape each vane almost-nothing bigger than the correct measure, the pressure exerted from de sides (first brick row) to the center, lift up the center of the complete polystyrene model in about 1?. I tried to down back the model by stay over with all my weight (nearly 180 pounds) and not only the model resist as hold the position!!!
                  Then, the oven dimensions are 39? diameter, 19? (planned 18?) height with a 12? by 21? door.
                  The complete dome and hearth were building with refractory bricks (using as little mortar as possible), being half bricks in the dome and entire (planed) bricks on the hearth (over the 2.5? slab)
                  That give us a 4.5? dome wall and a 5? hearth.
                  In my oven, the slab under the hearth (thermal mass) was isolated from the entire slab by 2? of 8-1 vermiculite-cement (a 42? slab square under the 39? diameter hearth)
                  The landing area was made from normal red bricks except by the four first bricks of the vent area that were refractory too (as could be seeing in the photos above).
                  The chimney will be of normal bricks ending with an 5? length and 6? diameter terracotta flue.

                  Next, some pictures showing the vent area. Please, note on fourth picture that the black surface on the lower sector is the door lintel.
                  I hope this helps.



                  • #10
                    No "trouble" accessing the Photo Sec. & "Terms"

                    (F) <fred_dinapoli@v...> wrote:
                    > Is anyone else having difficulty getting into the photo section of the
                    > site? I have gotton a "group error message" the last two days. I can
                    > get into the other sections w/o difficulty."

                    (M) I have, in the past, had difficulty posting images, but that was because my file size was too large. Now, I am in the Photo Section and can view thumbnails with no difficulty.

                    ================================================== ===========

                    (M) Because this Forum relies on very clear communication, I want to support James' recommendation that we all use the same "Terms".

                    James Bierney, the moderator of this Forum, wrote,in part: (Special fonts and colors added for emphasis by Marcel)

                    (JB) "I think for this group, we should use the term "foundation" for the concrete slab that sits on the ground, and "insulating hearth" (or "hearth") for the multi-layer hearth that rests on the the "stand" (typically made from concrete blocks). That might clear up any confusion on terms, and the difference between issues regarding the foundation and the hearth.
                    ================================================== ====
                    "Everything should be made as simple as possible, ...
                    but no simpler!" (Albert Einstein)


                    • #11

                      Hi guys; thank you for the advice, and I needed to be clear on definition. The slab, I meant is that I had a complete slab (patio slab poured) @ the same time I poured the hearth as well, that is why acalled it slab also. Regarding my insulation is that I did not get the chance to do the insulation first and then pour the rest of concrete for the hearth. I had a block wall and bbq pit and the the oven block walls done for me, but I laid out the entire walls with footings all around the block walls. I got hurt at work and cannot do the heavy work with my hands, and that limited my manual input or I would have done it the way you described it. So what I opted to do to compensate for the insulation is to double up on the base foundation with fire bricks, and offsetting the joints, I believe this will take care of the insulation. What do you guys think. I know it will be more work and material but I really do not have a choise.
                      By the way I will be insulating the entire oven once the brick work is completed with virmaculite insulation.

                      Thank you so much for the input, and like the pictures it makes it much more clear the steps and pattern.



                      • #12

                        Sorry guys, I forgot to ask a important question. Does anyone know or have installed a thermometer in the oven? I am looking into purchasing a thermometer tha thas a range up to 1,000?F, +/- 1?F. I am trying to think of the proper location on the height. The model I am loking at has a 12" long probe, and it mounts right into the oven. I believe it should be close to the middle. Any suggestions!

                        Thanks again.