copper gasket sealer ok to use for exhaust b-pipe?

it says withstands up to 700F, and id be applying it in addition to the existing gaskets. they arent the specific ones provided by greddy as i couldnt find any, so i tried the closest thing i could find but they still leak. will the copper sealer end up blowing out?

btw, ive used jbweld on the muffler before, and it just dries up and falls off like dry bread

You should be fine, I used some blue gasket maker made by Permatex on my composite gaskets I re-used w/ my old GReddy. I think it’s heat range was somewhere around 7-800°F.

composite? well i picked up the copper cuz the autozone guy said it should work. ill slobber the stuff all over it.