web analytics
fireclay or diatomaceous - 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!

Forno Bravo
See more
See less

fireclay or diatomaceous

  • Filter
  • Time
  • Show
Clear All
new posts

  • fireclay or diatomaceous

    I finally was able to reach my friend who gave me a bag of white cristal powder (I raised a question on my tread this morning, but I opened a new tread now as it deserves fresh focus)....this stuff is called DIATOMACEOUS.
    I thought it was fireclay as it was a left over from his oven....
    He told me that you insert/add this powder on top of the dome between the mortar and bricks and it is supposed to fill in when cracks happen.
    Diatomaceous earth consists of fossilized remains of diatoms, a type of hard-shelled algae.
    86% silica, 5% sodium, 3% magnesium and 2% iron
    Does anybody know about it?
    Diatomaceous earth - Wikipedia, the free encyclopedia
    I have a 25lb bag so I am going to use it to level the calsium silicate boards and on top of them to fill the gaps and then I'll follow his idea and put some on the dome.
    I thought to share this... Ciao Carlo
    Ciao Carlo

    Cost spreadsheet updated 4/22/08

    Pictures updated 5/28/08

  • #2
    Re: fireclay or diatomaceous

    So this is supposed to make the oven self-repairing like a punture proof tire ?
    Sharpei Diem.....Seize the wrinkle dog


    • #3
      Re: fireclay or diatomaceous

      that's what my friend was told...looking for more info...
      Ciao Carlo

      Cost spreadsheet updated 4/22/08

      Pictures updated 5/28/08


      • #4
        Re: fireclay or diatomaceous

        Here are the physical properties. It looks like it turns to silica ( glass ) when melted. However, the melting point is 1700 degrees C ( 3100 degrees F for others ) I don't think a pizza oven will reach those temperatures. If they did we could cook a 5 second pizza

        March 2001

        Amorphous diatomaceous earth
        Diatomite, uncalcined
        Diatomaceous earth, natural

        CAS No: 61790-53-2
        RTECS No: VV7311000 SiO2
        Molecular mass: 60.8

        TYPES OF
        HAZARD /
        FIRE Not combustible. In case of fire in the surroundings: all extinguishing agents allowed.

        Inhalation Cough. Local exhaust or breathing protection. Fresh air, rest. Refer for medical attention.
        Skin Dry skin. Roughness. Protective gloves. Rinse and then wash skin with water and soap.
        Eyes Redness. Pain. Safety goggles. First rinse with plenty of water for several minutes (remove contact lenses if easily possible), then take to a doctor.
        Ingestion Do not eat, drink, or smoke during work.

        Sweep spilled substance into containers; if appropriate, moisten first to prevent dusting. Wash away remainder with plenty of water. (Extra personal protection: P1 filter respirator for inert particles.)


        Physical State; Appearance

        Physical dangers
        Heating the material at high temperatures results in the formation of crystalline silica (see ICSC 0809 Cristobalite).

        Occupational exposure limits
        TLV (as silica amorphous): 10 mg/m E,I (ACGIH 2000).
        TLV (as silica amorphous): 3 mg/m E,R (ACGIH 2000).
        TLV: Intended change silica amorphous - insufficient data
        MAK: 4 mg/m (Inhalable fraction) Pregnancy risk group: C (DFG 2005).
        Routes of exposure
        The substance can be absorbed into the body by inhalation.

        Inhalation risk
        Evaporation at 20C is negligible; a harmful concentration of airborne particles can, however, be reached quickly when dispersed.

        Effects of long-term or repeated exposure
        The substance may have effects on the lungs, resulting in mild fibrosis (see Notes).

        Boiling point: >2200C
        Melting point: 1710C
        Density: 2.3 g/cm
        Solubility in water: none

        Typical Applications:
        A silica source in the production of calcium silicates, insulation bricks and material in safes, fireproof filing cabinets, etc. Used in the paint, varnish, lacquer, and polish industries. Used as an insecticide in gardens and in swimming pools as a filtering agent.
        Last edited by brokencookie; 04-06-2008, 04:15 PM.
        Sharpei Diem.....Seize the wrinkle dog


        • #5
          Re: fireclay or diatomaceous

          Insecticide and filtering agent! Will it cure baldness?

          I never understood where they came up with the "earth" on the name. Is it mined from old sea floor sediments?
          Everyone makes mistakes. The trick is to make mistakes when nobody is looking.



          • #6
            Re: fireclay or diatomaceous

            It is mined near bodies of water or old dry lake beds ( or seabeds). There are two varieties, saltwater and freshwater. The properties of each are a little different. "Diatomaceous earth consists of fossilized remains of diatoms, a type of hard-shelled algae." I checked the properties of the most common varieties and the melting temps are all very high. IMHO there must be something else that could be used as a self sealer. I have used a block sealer in my car that consists of a high copper content silica that becomes "glass" @ aobut 240 degrees F. A self sealing oven is kind of a neat idea but I think it would not be worth the trouble to set it up correctly. As we have seen, the cracks are only important to the builders ego, not the performance of the oven.

            Sharpei Diem.....Seize the wrinkle dog


            • #7
              Re: fireclay or diatomaceous

              Another bit of useless info on diatomaceous and diatoms: In the open ocean the small algae type organisms have either a calcium or a silca shell. When they die they start the slow descent to the ocean floor. At about 600 ft of depth, calcium goes into solution, literally it desolves into the sea water. The result is the silica based organisms reach the bottom and over eons develop quite thick layers. After even more geologic time some sea floors are lifted above sea level due to tectonic forces and these sediments become "diamomaceous earth". Under a microscope they are quite beautiful and the age of the sediment can be fairly accurately dated by the species of diatom present.

              These are spikey little devils and something one really doesn't want in one's lungs (or one's shorts! :-). They kill bugs by puncturing their hard exoskeleton and then they simply dry out, dissicate to death.

              See all that college wasn't wasted! LOL