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36" WF Pompeii Oven in Maryland - Forno Bravo Forum: The Wood-Fired Oven Community


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36" WF Pompeii Oven in Maryland

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  • #76
    Originally posted by JRPizza View Post
    If the oven wants to crack it will crack. I didn't have joints lined up so the crack in my oven just went right through a couple of bricks. I think it was david s that said you want your mortar to be weaker than your bricks - apparently not mine
    I’m not trying to ruffle feathers and I know we’re not building kilns and the thermal expansion we deal with is about half that of a kiln, BUT the principles remain. This from Daniel Rhodes , Kilns, design, construction and operation, Pitman publishing, (generally regarded as “the kiln builders bible”)

    ”Expansion joints must be provided in the brickwork of kilns. If no expansion space is provided for, the kiln will bulge and swell on heating due to the expansion of the bricks In practice, a space of about 1/4 inch is allowed between the ends of every third or fourth brick. This space should not be filled with mortar. More space than this is sometimes allowed just to be sure that the wall will not be too tight. In kiln building it is much better to have a loose structure than a tight one. For this reason the amateur may have a slight advantage over the professional mason, because his bricklaying is apt to be somewhat loose and not tightly locked together. I have seen kilns made by professional bricklayers which in use suffered severe cracking and swelling due to the overly tight and precise workmanship and the lack of expansion joints.”

    We’re talking around 1% expansion from ambient to stoneware temperature, so about 10 mm/m, or for an oven around half that from ambient to pizza temp. A 1/4” expansion pushing against a cooler outer decorative arch or base of the dome can certainly place stress on it if not a crack unless allowance is made. Although, as they say, there are two types of oven owners, those whose ovens have cracks and those who lie about their ovens having cracks. The same applies with kilns.
    Last edited by david s; 06-12-2019, 02:35 AM.
    Kindled with zeal and fired with passion.


    • #77
      Thanks guys! It almost gave me a heart attack when I saw the crack in the back... after all that work!

      I've now had ~5 fires that have gone over 1k degrees and the outer shell still is only around 100 degrees at the end a 5-6 hour pizza firing session (constant temps of ~850). Thankfully, the crack has not gotten any larger. I think I'm pretty much done with the build now and I wanted to sincerely thank everyone on the forum here for their expertise, especially @UtahBeehiver, @JRPizza , @Gulf , david s

      I've gone ahead and written up a 3 page guide of "Instructions for Making a Neopolitan Pizza in a Woodfire Oven" for when I have Pizza Picnics that I've laminated and just have out on the table when my friends/family are over and want to make a pizza, here's what I've got so far, feel free to use/suggest further edits: https://docs.google.com/document/d/1Pg3b7ion1Xklsl4efzIksRBt9K-p1DKBtByFcFn-XL4/edit?usp=sharing

      Thanks again to everyone here!

      The finished build:
      Click image for larger version  Name:	IMG_20190614_151728-(1).jpg Views:	1 Size:	510.1 KB ID:	414158
      Click image for larger version  Name:	IMG_20190614_151744.jpg Views:	1 Size:	393.8 KB ID:	414159