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Dreaming of oven for many years, now want to start

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  • Dreaming of oven for many years, now want to start

    FornoForumn team
    From SoCal USA, in the farmlands of Moorpark, CA.
    i have been dreaming of building my own oven for years and built a patio structure recently to home it. A labor of love.
    so far I have setup to have a 36” ID oven, but the more I read the more anxiety I get as I really don’t have any plans for how to build it.
    could anyone point me to finding some plans?
    so far, in have crafted the base, purchased and installed 2” insulation from FB and installed a base row using 1,3,1,1 mixed mortar with fire clay.

    ive read so much in the past days, almost getting apprehensive on the volume of information and ways to make it al, work.
    here’s my request for anyone who would be willing to guide

    1) I am struggling to plan the entry opening width of the arch
    2) I have put in a gas Pipe. Haven’t seen anyone do this so now I fear it’s a problem but it’s hard plumbed from the floor.
    3) Im concerned that i have left insufficient room in the front for the chimney at approximately 14.5” to my lip

    any comments are appreciated as I would rather tear out now than later.

  • #2
    First down load the cheap or even free plans from Forno Bravo, located in the resource section. It is a good baseline, a little dated, but will help with design and construction.

    1. A 36" ID oven requires a 6" ID chimney so the vent chamber needs at least the same square area opening as the chimney but it does not have to be round either. The width is builders choice but the height needs to be 63-65% of the dome height.
    2.Not many have pursued of the forum member have installed gas, perhaps a handful. FB and other third party supppliers do make gas option kits with the a safety flash back valves. It is highly recommended that gas installations be done by a certified plumber/fitter and with certified gas burner assemblies.
    3. It is hard to tell from the picture the placement of the entry bricks relative to the arch, they almost seem set in from the inside diameter of the dome rather than intersecting the dome.

    Read the plans and get back with the forum
    Google Photo Album []


    • #3
      Originally posted by golfguiedo View Post
      2) I have put in a gas Pipe. Haven’t seen anyone do this so now I fear it’s a problem but it’s hard plumbed from the floor.

      This seems like a cool idea. I'm a beginning member and haven't completed my build, but my novice thoughts on the gas line if you keep it: a) definitely put gas shut off before oven, which I'm sure you already have. b) maybe put a union right after the brick so you can quickly disconnect gas burner and replace with a cap for when you are using wood, so you don't damage your burner and it doesn't get in the way of your wood fire process / ash removal. I've no idea what temperature burners are generally rated for. Have you thought of how to regulate the temperature? manual metering valve or temperature control valve? If all parts are rated for the heat you intend to see and you intend to use gas often enough, it seems like the heat sync and other trade offs could be worth it.


      • #4
        There is an old saying about not mattering how fast you run if you don't know where you are going. Oven's are kind of like that in that it is best to have all the sizing/spacing sorted out before you start laying bricks. From your post I'm not sure how you got to where you are at without having a plan. If you have 14.5" (a brick and a half) from the dome arch to the front end of your stand you are probably good as long as the arch is properly placed (what Russell mentioned). After you have checked out the plans you should post a sketch of your dimensions as currently built. Do you have an IT or a plan to keep the dome bricks in their proper orientation? Did you place your arch so that the top bricks will properly intersect the dome? Letting us know where you are at and how you got there will help with any advice needed.
        My build thread


        • #5
          thank you all three for your 1st comments. I found all your responses in my Junk folder- - wow, gotta love it.

          Mr Utahbeehiver-For over a year i have had the 73 page document downloaded from FB, but I don't think of these as plans, they are more a description of the process that I need to go thru. By plans, I think of something with actual dimensions, and that is something I have never been able to locate on FB. it's titled "Pompeii Oven Instruction v2". Although this never talked about gas, the FB ovens all had the gas kits in them as options, and I thought it was a no-brainer to do. Not so sure as I have yet to see anyone with a fire starter since opening up the builds.

          1) acknowledged I read 6" and 8". thx for that confirmation, 6" will do. I don't quite get the meaning of 65% of dome height, do you mean 65% higher than the dome height so ~72" total height (44"x1.65) to create the proper draft? 2) will investigate. 3) Intended to intersect the dome at the cut line. Again maybe this is where my lack of a plan is hurting me, but following what I see.

          Yes, I actually have (2) shutoffs. Normal 1/4 turn certified NSF and then the fireplace petcock. The gas line intended as fire starter only. It has shutoff at the front of the oven, under the entry nearly 4' from the output. Have only intentions to use it for starter and then off position, once lit.

          JR Pizza - I have absolutely the same feeling, any road will do if you have no path in mind. I have read over and over the Pompeii instructions, and have been digging into the builds with pictures for weeks, reading the forum for newbies. That all said, my 1st major questions came when I couldn't find folks talking about the entry opening width to calculate for a 36"ID. I plan a 1/2 circle entrance, & have the template to cut keys to make that happen in the trapezoidal shape that mimics the artist GiannoFocaccia's arch and entry. Many are nice, that one caught my eye.

          So is there some detailed plans with dimensions I have missed? I have tried the resources pages, but found nothing so far. I thank you all for taking your valuable time to reply. I find your accomplishments motivating and at the same time daunting task I have undertaken. almost paralyzing in terms of how much details you have worked into each section.

          At this point, I hope to ensure 1) I set the inside arch well 2) have adequate space for a vent (hopefully within my planned space I setup) 3) locate some detailed drawings if any exist to manipulate into my 36"

          I am sure if you notice anything, you'll not hesitate to speak up and point it out. that's why I joined. Of course, I am happy to house a fellow builder if anyone is loving CA, and wants a 2 week Pompeii Vacation! Mighty nice here these days...

          all the best and look forward to your responses.


          • #6
            There really is not a cook book step1, step 2 etc.or exact dimensions since every build is different in terms size, material, enclosed, not enclosed. etc. The eplans V2 are guidelines/baseline and over 10 years old and the gas option was not available then by FB but they do show a kit of their website not.There is "sticky" in the Newbie Section that is called Treasure in Archives or something like that that has some of the more documented builds. The inner arch "height" is 65% of the height of the dome, dome height = 18" or should be, so 0.65 x 18 = 11.7" as I mentioned before "width" is builder's choice but you need to leave a reveal on the arch and vent chamber to allow a door to seal the dome, do a search on reveal if you are uncertain what this is. Attached is a pic of where the bottom course of the inner arch and the ID of the dome need to intersect.

            Click image for larger version

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            Google Photo Album []


            • #7
              Do you have any CAD skills? I have some files for a 36 inch oven laying around that I build using Freecad that I could share if you would like. I think going with the hemispherical arch is a good choice. You need to figure out how tall you want your door opening to be so you can make sure that a brick sitting on the top of your arch will "become" part of the dome as it builds up. You can see a shot of my CAD side view at the link below. My oven is a 39" with a 12.25 height, and you can see how I placed a brick at that height which allowed me to set the arch distance from the oven centerline.
              With a hemispherical arch, the opening width usually works out to be twice the radius of the arch. I built mine with a 9.75" radius, which gave me a 19.5" wide opening. Since my height was 12.25" my 9.75" radius sits on a full non tapered brick (2.5" thick) I also made an arch calculator spread sheet to help figure out the taper on the arch brick I can share if you want.

              My build thread


              • #8
                I pulled together this visio drawing trying to understand if really the opening would be 23.4" (11.7x2). Was not expecting this large of an opening. Then trying to visualize the cuts for the left/right side. and where the flue woulbe be located from the face. Lastly if a 1" reveal could work. Hope this translated document opens and is legible.

                JR - I would gladly like to see your plans and your calculator


                • #9
                  Using a full arch the width will be the height x 2. Can go down to abt 63% and be fine, in fact I have seen a few lower than that. The 63-65% of dome height is a rule of thumb. But the width at 11.7 is correct. If you go with a partial arch as in fig 2. then as long as the top the arch is at the 11.7 (width is adujustable) you can go that way be aware that the lower the profile of this type of arch the more outward pressure is place on the vertical wall and may require buttressing depending on the type of chimney you install. FYI, consider what is call a tapered inner arch, this makes the transition and tie-in to the dome to the arch much easier. A lot of builders use this method, I did it, JR, etc. You actually did one with the trapezoidal brick template in one of your pics. But get back with us latter on this, It is one of the most difficult concepts to visualize.

                  The current drawings only show 1/2 bricks on the arch. In order to do a tapered inner arch you start with whole bricks. 1" reveal is fine. Inner ar
                  Google Photo Album []


                  • #10
                    Arch height and arch radius don't have to be identical, which is what I tried to explain in my post above but apparently was not clear enough. Look at the attached pic. My opening is 12.25" tall but only 19.5" wide. The way to do this is pick a width, let 1/2 the width define the radius, and make up the height difference with flat bricks underneath the hemispherical part of the arch to raise it to the desired level. With my 39" oven, using a full thickness brick @2.5" raised my opening to the height I wanted while keeping my width reasonable.
                    My build thread


                    • #11
                      The FB plans recommend for a 36" to have an opening height of 12" and a width of 19", which is a 66.67% ratio. If you stuck with this you would have a 9.5" height, a 19" width, and could use a full brick under the arch to hit their recommended height. I know the ratio is kind of at the high end and don't know why they recommend it but possibly so you could use a full brick under the hemisphere? I like the 39" oven dimensions as my height worked out to be 62.82%. You could use a full brick and their dimensions or shave down a brick to hit something you might be more comfortable with. You could also ask forum members that used the FB dimensions how well their oven "breathes".
                      My build thread


                      • #12
                        Thx Russell. Getting an early start today so lets see what progress I can make. 1st course is all cut and will soon have both sides. Getting ready to make my IT so that I can set the 1st course.

                        1) Regarding the process of soaking the bricks in advance. How long is typical?
                        2) Also can you advise the benefits of cutting every brick as a taper vs setting the net rows with non tapered bricks and having "triangles of mortor"? As no-one ever sees the outside, I am sure there must be a functional reason to benefit cutting every brick in half, then both sides of the 1/2 brick again..
                        3) On the inner arch, will I find that every brick be a full brick, (with the nice side facing out?), and will they all be the same as the bottom left/right sides?
                        4) On the homemade mortors. Has anyone commented on benefits of fine sand vs courser sand? I bought a bag of 30 that I used based on someone else's comments that 60 was too large. Appreciate your knowledge.
                        5) What the impact if I shrink the oven size by 1" (17.5) and the ratio jumps to 67% vs 63-65%. IS a higher ration better or worse and Should I address that by lowering the height of inner arch?

                        Pizza for 4th of July is a goal but who knows if that's realistic or a long shot.

                        One final thing, I what amazed by your craftsmanship as I had not seen your build until this morning,when I hit your link. T he copper dome is amazing. The attention to details was impressive. Hope I have half of your patience in me for this one!.


                        • #13
                          I see you have an arch form - what dimensions did you settle on? Also I can't tell if you have any shims under the form or have allowed for them, but the ability to remove shims and drop down the form for removal will greatly facilitate getting the form out without having to destroy it or disturb arch bricks.
                          My build thread


                          • #14
                            I get it now and I prefer to lessen my opening as well, but I have a built consequence. For even inch I shorten the opening, I move outward on the radius about 1" opr more. So by shortening by 2" where the opening intersects the walls. I have not enough allowance to have my entrance chamber move outward further. as it will overhang the slab. So I am left with a decision a) to move the opening inward and as such, the opening will not be flush with the walls, it will be 1.5" inward of the walls. (red marks on board) or b) make my oven smaller :>( or c) keep a larger opening. Anything you suggest i consider?


                            • #15
                              1. Depends on a lot of variables, the brick, the temp, the humidity, etc, you just have to experiment. Like the three bears, too long, mortar slides off, too dry, mortar set to fast and may crack, just right, holds mortar but allows enough time to adjust and tamp.
                              2. No you do not need to taper but you will need to bevel and you move up in courses to avoid what is called "inverted" V. You only need to bevel the top and inside of the bricks no the whole side. I did both full taper and bevels but if I built another I would do just as I explained. JR Pizza did this. mortar in the back side, it is your friend.
                              3. Does not matter, it is the inner arch and most is covered up by the vent chamber bricks. The tapered arch bricks are unique, so you don't cut them all the same (they start as a full brick but are cut dow, with the exception of arch taper to get uniform joint thickness (looking towards the oven opening)
                              4. I just used a builder quartz sand, not play ground sand.
                              5. Like I said, it is rule of thumb but you should be able to reach this ration by adjusting the arch and first course.,
                              Fourth of Jul;y is an aggressive schedule when you take in curing time, etc. But you know how much time you have.

                              The correctly placed and configures IT is important, post a sketch of what you are planning before you build. Critical items, pivot point needs to be at floor elevation if possible ( I did not do this back in 2012 and had to make adjustments as I went up). Pivot point, along the IT rod to the L bracket must intersect the half thickness of your brick, adjustable in length.
                              Google Photo Album []