Not for bbq smoker modification

I could be misleading you with this review because I used it for my bbq smoker instead of a furnace, but I figured heat is heat so... I bought this to seal up the gaps in my new smoker (before ever using the smoker). After the first smoke, I never took it over 320 degrees and this stuff started to peel right off. After the second smoke, the rest started to pop and crack and now all the gaps are back.

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