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Firebrick composition-what's good and bad? - Forno Bravo Forum: The Wood-Fired Oven Community



I'm Peter Reinhart! Ask Me Anything! Monday, February 15, 2016 7:00-8:00 pm EST

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.

Ask Me Anything New Forum Feature

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.

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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Firebrick composition-what's good and bad?

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  • Firebrick composition-what's good and bad?

    I've been looking at firebricks and have found a few options with differing alumina/silica content. The closest I've found so far has 33% alumina and 63% silica (with ferric oxide, titania and accessory oxides all about 1.5%).
    Is this too much silica or won't it make much difference?
    The suppliers class this as a high duty firebrick - their low duty has about 23% alumina/73% silica. Which is more important to have the higher content??

  • #2
    Re: Firebrick composition-what's good and bad?

    The reason the plans advise against high duty brick is cost and the fact that some high duty bricks are insulating bricks - poor thermal mass. I don't know whether the chemical composition matters as much to this as the method of construction. The weight of the brick helps to assess this - heavier bricks are generally better. Can you obtain the low duty bricks from this supplier? That would probably be ideal.


    • #3
      Re: Firebrick composition-what's good and bad?

      It sounds like the bricks you have found are perfect. 30-odd% is just what you are looking for.

      We only recommended against high duty firebricks because they are very high in alumina (I don't remember the exact figure, but I think it is something like 60%), and could get too hot when you have a big fire, and then give up heat too fast once the fire was out and you wanted to cook with retained heat. A few % +/- isn't a big deal.
      Go for it.
      Pizza Ovens
      Outdoor Fireplaces


      • #4
        Re: Firebrick composition-what's good and bad?

        Same supplier can do low/medium/high bricks. Thks for the info. The manual labor side of the project doesn't worry me but some of the technical aspects can get me a bit confused.