High temperature sealant for SS hoses 1200 °F with NPT thread

[Stefan2211]

Hello,
we have flexible hoses in SS for high temperature exhaust gases (mainly nitrogen) up to 1200°F. Does anyone has experiences with one of the following sealants
X-Pando, Deacon 8875-Thin,Flexitallic Graoil GTS and Loctite NS 5550?

Is any of these sealants long lasting and can hot/cold cycles?

Thanks

 

[btrueblood]

Flexible hoses themselves don't really hold up at those temperatures (the sealant material inside the slip joints bakes out over time and becomes brittle, then fails). Any pipe thread "sealant" will work ok until it is flexed, or thermally cycled. Solid pipe, with welded flanges and metal crush gaskets, work for automobiles and are pretty much the only thing you see on production vehicles, for good reason.