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Muffler Putty for patching

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  • Muffler Putty for patching

    Hi All,

    Anyone ever thought of, or has tried to use muffler putty to fill small gaps and cracks in their castable domes. I have a few small places that could use some cosmetic filling. Was going to get some High Temp mortar Mix but then I though why not muffler putty. Here's a link to one of dozens of products.


    Just curious!

    Cheers JB

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  • #2
    Not tried it, could be a goer. But I should think a mix of the same material you used for the casting would be preferable. The job needs to be done while the casting is still moist though, otherwise you won’t get a decent bond and the filling material may dry too fast for the hydration process to take place properly. You may also need to sieve the sand so there’s only really fine stuff in the mix.
    Last edited by david s; 11-02-2018, 03:49 AM.
    Kindled with zeal and fired with passion.


    • #3
      Hi Dave,

      I agree. I'm still curious though. I think I'll try it. Do some patching with some high heat mortar, some with homebrew and some with muffler putty and let everyone know how I go in a few weeks time when I fire this sucker up!!

      Cheers JB


      • #4
        The SDS says the Permatex Muffler putty contains sodium silicate. The SDS says potential decomposition product is carbon oxides. This leads me to believe that the muffler putty is probably a filler like limesand (crushed or ground calcium carbonate/limestone) mixed with sodium silicate and water.
        I think, therefore, that it would make a better crack repairer for you oven than it does muffler putty. I base this on the grounds that it would probably not be very flexible when hardened, which would be more of a problem on an exhaust system than an oven.


        • #5
          I had some cracks I repaired using a fireplace repair mortar that has the consistency of caulking (a little wetter) -

          The jury is still out on its effectiveness but it was easy to use. Apparently it bonds well and sets rock hard.



          • #6
            Hi Guys,

            Called into Bunnings today for some other bits and pieces and they were sold out of Muffler Putty. I also checked out the tubes of high heat silicone sealants but they weren't rated for much over 200C so I didn't worry about getting that. I did come across a tub of Selleys Fire Cement which looked like it would be good but at $39 for a small tub I had to pass. Will see what I can find during the course of the week. Will keep everyone posted.