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  • Floor cooling too quickly

    I finished my oven in November, and have used it 6-7 times now, and have noticed that my floor seems to be cooling too quickly. My cooking process is to heat until fully cleared, 2-3 hours, then spread coals around and let sit a few more minutes, then push the fire to one corner and start making pizza. Using my IR thermometer, it reads about 750.
    I usually do 6-10 pizzas, usually the first burns a little too much, pizza 3-5 are perfect , then pizza 6+ the floor is down to 650 and I no longer get that wonderful char you expect from a wood fired oven.
    My floor is 2" p-crete, 2" casi board, then firebrick. It is an outdoor oven with stucco exterior, but I tarp it when not in use .
    Have have a few theories , first is that moisture is getting in the floor, second is that my firebrick was not the right kind.
    My dome uses high-duty heavy bricks, but for the floor I use some lighter stuff I bought new. They said it was rated to 1800, and great for pizza ovens, but it's so much lighter and easier to break than my other brick.

    Any suggestions on ways to improve this, or what my problem is?
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  • #2
    Dan,

    You may well have some moisture issues. But, first I have a few questions. Can you post a pic of your floor brick. What are their diminsions? Do you have one left over that you can weigh dry? Can you get a product data sheet or a manufacturer and product name from your supplier?
    joe watson

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    • #3
      Sounds like you may have used insulating firebricks on the floor. You need dense firebrick which should be around 1.8- 2.0 kg/ litre. Measure a leftover brick, if you have any, weigh it and compare density.
      Kindled with zeal and fired with passion.

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      • #4
        Insulating firebrick would be white (edit: and so soft your oven would be practically unusable), so pretty easy to ID without weighing - but I doubt this is the issue.

        From how you describe your performance, it sounds like a fire management issue. The oven floor going to 650 after 6-10 pizzas is normal. If you are not keeping a good flame in your fire licking up the side of the oven, the temp will drop. Always keep a small log (size of your wrist or so) burning - flame licking up the side about to the top. If the floor temp still gets too low - then bank the fire on the other side of the oven and start cooking where the coals were.
        Last edited by deejayoh; 01-16-2017, 11:49 AM.
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        • #5
          Here is a picture of my oven during cooking, I'll double check my bricks when I get home later today.
          It may just be normal behavior, or a fire management issue as well. I always keep a log going, but pizzas after #5 are sub-par. Should I be cooking as soon as the dome clears, or would leaving the fire going a little longer be beneficial?
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          • #6
            Good news, that appears to me to be firebrick. But I'd say you need to keep a bigger fire than what I see in that picture to keep up temps. I struggled a bit with my oven losing temp until I realized the solution was MORE FIRE!

            Check out the chapter in "The Art of Wood Fired Cooking" on oven management that starts at page 23: https://books.google.com/books?id=bP...page&q&f=false
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            • #7
              Deejayoh is probably spot on with his assessment. But, your statement:

              Have have a few theories , first is that moisture is getting in the floor, second is that my firebrick was not the right kind.
              My dome uses high-duty heavy bricks, but for the floor I use some lighter stuff I bought new. They said it was rated to 1800, and great for pizza ovens, but it's so much lighter and easier to break than my other brick.
              still raises a consern with me. "Easier to break" does not consern me as much as "so much lighter". From years of scrounging and hoarding, I have samples of super duty, high, medium, and light duty (clay) firebrick. Though, there is a significant amount of difference in their hardness, there is not a very noticeable difference in their weight. At least none that you would notice by palming. One refractory brick that I have on hand does. It is sodium silicate. It is much harder than an insulated fire brick but, not as hard a light duty fire brick. It is a lot heavier than an insulated fire brick but not near as heavy as a minimum duty fire brick. From your pic of the oven floor I'm still not sure. If you have a spare brick with a fresh break I could possibly tell from veiwing a pic. This type of brick has made it's way into ovens before. I'm just trying to rule that out.
              Last edited by Gulf; 01-16-2017, 06:42 PM.
              joe watson

              "A year from now, you will wish that you had started today "

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              • #8
                Originally posted by danjmath View Post
                Here is a picture of my oven during cooking, I'll double check my bricks when I get home later today.
                It may just be normal behavior, or a fire management issue as well. I always keep a log going, but pizzas after #5 are sub-par. Should I be cooking as soon as the dome clears, or would leaving the fire going a little longer be beneficial?
                that looks a very cool fire compared to what i have when cookin pizza i would try what deejayoh suggested and have more fire and change sides

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                • #9
                  Ahh, I am very glad the answer is "MORE FIRE!". To achieve this should I just use more wood? Also, once I am cooking, should I use more than 1 log just burning? (Also, wood quality is probably a problem, my wood has not been seasoned very long, although I do put a new load in the oven when it gets to ~300 degrees after the previous days fire).

                  @deejayoh I have attached the some pictures of the 2 types of firebrick I used, after looking at them again, I think some of the weight difference is just from the size, but I still am pretty sure the dome stuff is heavier.
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                  • #10
                    Those are just two different densities of firebrick. The heavier one is really heavy as it is only slightly bigger than the smaller one, but double the weight. You need more Fire Scotty!
                    FWIW the opening is pretty big compared to the size of the oven, so you are losing some heat with that big hole in the side. Also I would push the fire to one side or the other instead of all around the back. This will give you some really hot areas in the back to cook with and then cooler areas in the door to use as well. A slight design change gives you more usable space but it is a little late for that now. Just keep the wood coming. You really haven't got the oven broke in yet at 7-8 bakes, so more pizza and more wood.
                    The cost of living continues to skyrocket, and yet it remains a popular choice.

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                    • #11
                      Not broke in? Guess it's time to make more pizza! Just need to find more good wood.....
                      Thanks for the input everyone.
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                      • #12
                        Originally posted by danjmath View Post
                        Ahh, I am very glad the answer is "MORE FIRE!". To achieve this should I just use more wood? Also, once I am cooking, should I use more than 1 log just burning? (Also, wood quality is probably a problem, my wood has not been seasoned very long, although I do put a new load in the oven when it gets to ~300 degrees after the previous days fire).

                        @deejayoh I have attached the some pictures of the 2 types of firebrick I used, after looking at them again, I think some of the weight difference is just from the size, but I still am pretty sure the dome stuff is heavier.
                        It is the density of the brick that is important, so without knowing the measurements of your two bricks it is impossible to know their volume and therefore calculate their density. Also the bricks must be dry as any absorbed moisture in a porous brick will increase its weight and give a false density reading.

                        1. Measure your bricks in centimetres and work out their volumes (this will be in cubic centimetres, so divide by 1000 to get volume in litres.
                        2. Density = Mass/Volume, so weigh the dry brick (in Kilograms) and divide by the volume (litres) to get the Density in Kg/Litre.

                        As stated in post #3 the density should be in the range of 1.8 - 2.0 kg/Litre (same as g/cm3)

                        3. Repeat for the second brick to compare their density.

                        Generally there are only two types of firebrick, insulating and dense, where insulating firebricks are typically less than half the density of dense firebricks. There can be still considerable difference in density of the harder dense firebricks though, generally the higher duty bricks are denser than the lower duty ones.
                        Last edited by david s; 01-25-2017, 03:24 PM.
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