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Insulation - Forno Bravo Forum: The Wood-Fired Oven Community



New Forno Bravo Forum Feature

Forno Bravo Forum Community,

You will notice a new forum at the top of the main page called, "Ask Me Anything". This forum will be used for live one hour "Ask Me Anything" (AMA) sessions hosted by people who are knowledgeable in different areas pertaining to wood fired ovens. How it works:
- Each AMA will have a "sticky" thread where the community can post questions they would like answered during the live session. This will allow everyone to participate even if you can't be online for the live session. These questions will not be answered by the host until the live AMA; if you need an answer quickly, you should post it in the appropriate Forum area for the community to respond.
- Another thread will be posted for the live AMA. Registered users who are logged in during the live session can interact with the host by asking questions and receiving responses.
- The live thread will remain in the AMA forum to view after the session.

To kick off our AMA feature, we have invited author, chef and master bread maker and host of Pizza Quest, Peter Reinhart, to be our first host! Peter will be in the Forum on Monday, February 15th, from 7:00 - 8:00 pm EST. If you are unable to be online during the live session, you can post your questions in the sticky post. Peter will answer those questions during the live session on February 15th. You can view Peter's answers to your questions as well as what happened during the live session in the session thread.

We hope you enjoy this new feature! Please let us know if there is a topic that you'd like to have as an AMA and we'll look for a host!

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  • Insulation

    James, I've read your recommendations on using 1" of 6# insulating blanket. I'm building a 36" igloo style oven and will finish up the oven brickwork this coming w/e. Based on the rec's, next comes the 1" blanket, then 4" of perlcrete. I'll try to post some pics shortly...

    Can I skip the blanket? If I were to skip the blanket, do I need a slip plane between the oven and the perlcrete? Is 5" or 6" of perlcrete enough to compensate for omitting the blanket? Anyone else got an opinion/experience to add?

    btw, for anyone just getting started, harbor freight (www.harborfreight.com) has a 10" brick/tile wetsaw on sale for $199. It's not a name brand but for the money...

    Thanks for all the help!
    Last edited by DavidK; 12-15-2005, 10:02 AM.

  • #2
    It's intereesting that there are two reasons to insulate something -- either to keep heat in, where you want it, or to keep it from getting to somewhere that you don't want it. The first is the logic behind using an insulating blanket. It is more efficient than vermiculite/perlite, so it does a good job of keeping heat inside the oven. The other reason to consider using it is to provide a solid layer that will help keep loose insulation from ever working its way into the oven through a crack or seam. A blanket does cost a little more than buying the extra couple bags of vermiculite.

    2" of loose insulation is close to 1" of woven ceramic blanket, so if you go to 5"-6" loose, you won't get heat on your enclosure walls.

    You don't have to worry about a slip plane -- vermiculite loose or casted with portland cement isn't solid enough for that to matter.

    Hope this is helpful.
    Last edited by james; 12-15-2005, 11:30 AM.
    Pizza Ovens
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    • #3
      Thanks James. Your guidance is always helpful! Since my oven will be finished as an igloo, it will have a cast insulating shell with the final layer being stucco. So as I read it, a 6" layer is equal to 4" perlcrete + 1" blanket.

      As for the blanket, Thermal Products is charging $1/sf or $49.50/box, so based on my calculations, I only need about 24sf. Add shipping and we're talking $30-ish. That's more than reasonable as far as ROI, but for me, it isn't the cost but a burning desire to steam ahead without being slowed by a 7-10 day UPS delivery... Decisions, decisions.

      btw, Thermal Products is only carrying #8 1"x24" insulfrax now, but the price seems more than reasonable...