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  • I have 4 questions...who's up to the challenge??

    Ok Forno Bravo peeps I'm In the middle of the build and I have the following questions (More to follow )

    Quick Stats: The oven build is a 42" Pompeii build in North East Ohio that will be in an enclosure.

    1) I have Ceramic Fire blanket that I will be using to insulate the dome...Do I need to add an additional V-crete layer and then a stucco layer? (or is that unnecessary being that the oven will be in an enclosure)
    2) Can I / should I cure the oven with the Ceramic Fire blanket attached? (if so, is the week wait sufficient before curing??)
    Part b. With the fire blanket and V-crete layers? (Do I need to wait longer before curing?)
    Part c. With blanket, V-crete, and stucco layer? (Do I need to wait even longer before curing?)
    3) How Important is a thermal break and where should it be placed?
    4) Circling back to the 3" fire blanket layer...is that enough insulation on it's own to keep the oven hot enough for pizzas all night? And then after removing the fire from the oven, to bake bread in the oven next day?

    Sorry for all of the question and I have done some research on these questions in the forum but what I found was not an exact match for the my questions / next steps of the build...thanks so much!! Zoo

  • #2
    The vermicrete layer over the blanket is just to even out the shape and to provide a firm substrate to work the stucco on. If you are building an enclosure there is no need for either vermicrete or stucco, although if you are concerned that the blanket might become a home for rodents you could cover it with say a 6:1 vermicrete that should be strong enough but not so heavy that it will compress the blanket.
    3 blanket should be fine, but for pizza you need to maintain a fire on the side during cooking.
    Kindled with zeal and fired with passion.

    Comment


    • #3
      David answered #1, here's my take on the rest:
      2 - I didn't wait for the blanket but many say it can help to reduce cracking by allowing more even heating of the structure. Mine did crack so maybe that was part of the problem. If I built another oven I'd probably wait. A week should be OK to wait but just take it low and slow. Maybe even put an incandescent or heat lamp inside to provide a little heat to drive moisture while you are waiting for a fire. When you do start consider using charcoal or what David and others from the southern hemisphere call "heat beads". Can't comment on parts a and b as I cured before I put on my stucco.
      3 - Lots of discussion on this by smart people and no two ovens identical enough to each other besides a heat break to get data from, but for all the cost and time building an oven I felt taking a little more effort to put in an air gap and buying some insulating rope was worth it. My philosophy has always been if you don't know exactly how good something needs to be, just do the best job you can. If you build your vent arch larger than the inner arch to provide a reveal to seal a door against, making a gap is really a trivial matter. Lots of pics here on the forum.
      4 - Like David says, you need a live fire for pizza. I have about 3" of blanket. For pizza, I fire my oven for at least 2 hours (low and slow), then push to the side and cook pies with some bright flame going which really helps cook the top (bottom cooks super fast from contact with the floor). After pizza I usually get a small fire going in the middle for about another hour, or longer if I want the oven aroung 50-0 in the morning. Otherwise after an hour or so I put my door on. Depending on how long I did the second firing I'm usually still in the upper 400's by mid-morning. We will cook a few chickens (they will be done in an hour or less) then put in some roasts later in the afternoon, or the following day if I want to cook really slow. Obviously you will have lower temperatures in the morning during your winters, but 3" of blanket should be plenty, especially if you have enough in the floor (I have 5" of board) and a good door.
      My build thread
      http://www.fornobravo.com/community/...h-corner-build

      Comment


      • #4
        I agree with JR on all the points. I cured my oven with the blanket on and i do not know of any cracks in the oven. I also waited a few weeks to do the fires because i wanted to have my enclosure done.

        3 it is highly recommended to leave a reveal for a door and once you do that the heat breaks are not a big deal just a thick sheet of cardboard as a spacer and try to minimize the contact patch and then stuff with rope and seal up. That is really a very easy thing to do and why not it can't hurt.

        4 i fire for probably 3 hrs or maybe longer to get it nice and hot and keep a nice fire going on the side and i will keep it going for a while after i am done. When i put the door on the next day i have been as high as 700F and normally in the 600F range. If you insulate it properly it can hold heat for a long time mine will take up to 10days to fully cool off.

        Comment


        • #5
          Hey guys! Thanks for the responses thus far....I only have 2 1/2 inches of fiber board under the floor....I noticed JR said he has 5....wow! no heat is getting through that lol! A follow up question to the posts would be can I construct the dome, wrap in blanket, then V-crete, then stucco the exterior, and THEN cure the oven? Thoughts??? I'm super paranoid about water getting into the insulation even though it will be covered, because the walls of the enclosure will be glued pavers that essentially will be dry stacked it will allow for some moisture pass through into the enclosure. I do have the fiber board sitting on top of some 3/8th Durock sheets that I treated with "redguard" moisture barrier to keep water from wicking up into the insulation boards.

          Comment


          • #6
            If you are building an enclosure then there is little point in doing vermicrete and stucco layers as well. I always do the drying fires before adding the stucco layer because it will want to hold moisture in, making driving the water out far more difficult. In your case, as you are doing an enclosure id be doing the drying fires after one layer of blanket, then add one or two more, then maybe a cap of 6:1 vermicrete over the top as suggested before finishing your enclosure and roof.
            Kindled with zeal and fired with passion.

            Comment


            • #7
              I live in Cleveland Heights and built an oven three years ago and it works perfectly. General rundown 36 floor 2 of ceramic board under firebrick floor, firebrick dome home brew mortar, 3 ceramic fiber insulation, wire over that, stucco with structural fibers added, put a truck transmission pressure valve that screws through the stucco to vent any moisture, 6 stainless double wall chimney, I did a cast entry arch that is separated 1/8 from the dome. We use it all year not one problem. Oh also used a waterproofing paint for the stucco.

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              • #8
                Nicely done

                Comment


                • #9
                  Originally posted by Rock 71 View Post
                  I live in Cleveland Heights and built an oven three years ago and it works perfectly. General rundown 36 floor 2 of ceramic board under firebrick floor, firebrick dome home brew mortar, 3 ceramic fiber insulation, wire over that, stucco with structural fibers added, put a truck transmission pressure valve that screws through the stucco to vent any moisture, 6 stainless double wall chimney, I did a cast entry arch that is separated 1/8 from the dome. We use it all year not one problem. Oh also used a waterproofing paint for the stucco.
                  Very nice!! Glad to hear that there is someone in my general vicinity that uses the oven all year long without issues...enjoy!

                  Comment


                  • #10
                    I'm in the Boston area and used the oven all winter with no issues. 4" of insulation under the floor, 5" over the dome, no thermal break then fully inclosed in a house-like structure (the pizza hut) with no vcrete or stucco. I've thought about pouring perlite down the chimney chase to fill the building, but I'm not sure that that would really add anything at this point. It's typically 6-700 degrees the next morning after pizza, I need to cool it down for bread; then 350 the next day, great for pot roasts and such. A thermal break might have given me a bit more heat retention, but so far don't miss it at all. Thats with a really bad door-- a piece of backer board reinforced with plywood. Really need to make a better door!
                    My build thread: https://tinyurl.com/y8bx7hbd

                    Comment


                    • #11
                      I think you are at the sweet point on the amount insulation, any more has diminishing returns. You probably hit it on the button with a better door but to be 6-700 F the next day is great from my perspective.
                      Russell
                      Google Photo Album [https://photos.google.com/share/AF1Q...JneXVXc3hVNHd3/]

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