In terms of 'similar' do you mean in terms of application, color, chemical resistance, elasticity, etc? You're going to hit the most points just with
a standard high-temperature silicone like Permatex Hi-Temp, but I am not sure if that is going to be sufficiently structurally sound enough to anchor
into. Then again it all depends on your surface area contact and if you're doing this smart enough if the anchor will hold. For example if you
undercut whatever area you are filling in with silicone so that the seam/hold gets larger toward the bottom then it will wedge itself as upward
pressure is applied from the anchor. Personally I used to use fireplace cement for high-temperature applications but those were much higher than
400F, and at that temperature you won't even be able to cure fireplace cement. |