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Adding Graphene aka Carbon Nanotubes to Homebrew or Refractory

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  • Adding Graphene aka Carbon Nanotubes to Homebrew or Refractory

    Hello fellow oven builders,

    In another post, David S mentions using carbon nanotubes as an admixture for the castable dome concrete mix. The product he uses is called Edencrete, however, after researching the tech, it appears there are many suppliers, I was able to find some on Alibaba in both liquid/paste and powder form. I wonder if anyone can contribute some tribal knowledge on actually using the stuff, finding dosage info in layman terms is proving to be difficult.

    Anyone planning to cast a dome should definitely look into it. For my first/only oven, I used 3:1:1:1 homebrew with polypro burnout fibers, and though the oven works great, I was not satisfied with the perceived hardness of the final product and ease of dinging the wall. My current project will be a bit bigger and I don't want to worry about eventual collapse, I think graphene aka carbon nanotubes will address the issue.

    Looking forward to your thoughts.
    Robi
    Last edited by robi; 01-19-2022, 05:51 PM.

  • #2
    I doubt whether you'll find any information regarding graphene use in a castable for this application, although there is some info at lab scale suggesting its ok for refractory use. Edencrete don't have any testing for this application although their chief scientist tells me there's no reason it can't be used. Their admix is designed for standard Portland cement concrete for which they have done a lot of testing. I have performed my own tests with a sample bar breaking device and recorded flexural strength gains of 50%. There is another company developing a graphene admix for concrete but they have not yet developed a liquid admix of have a product certified for sale as a concrete strength enhancer. Adding powdered graphene apparently has dosage and mixing issues which can easily result in inconsistent strength. I use both stainless needles and AR glass fibres in conjunction with castable refractory. As the glass fibres have a melting point of around 900C, that is well north of the temperatures we use. I don't think any other oven manufacturers use fibre reinforcing in their castings. I'm sure that they would say if they do use them and I've not seen any reference to it.

    As you've said in the title of this thread "Graphene AKA carbon nanotubes" that is not quite accurate. There are many forms of graphite morphologies, nano tubes, nano onions, graphene etc. The names generally describe their form. Nano tubes are essentially sheets of graphene that form themselves into tubes. As a strength enhancement for concretes both graphene and nanotubes produce similar results in testing ie around 35% increase in both flexural and compressive strength,
    Last edited by david s; 01-19-2022, 08:07 PM.
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