Anyone use one of these? I'd like to add it to my 10 gal. SS brewpot, but I wanted to know how well it holds up. Seems like even high temp o-rings wouldn't survive too long.
I'm not familiar with Fermentap spigot, but a properly designed and installed weldless fitting should have the O-ring on the inside of the kettle where it will never be exposed to temperatures higher than the 212F boiling wort so long as there is liquid in the kettle. You shouldn't have any problems with it.
Silicon o-rings are rated for like 250F. Can't say I've seen the fermcap weldless used but they look exactly like the one from Bargain Fittings or any other store, so I'd guess they would work. Probably cost too much though.
Silicone o-rings are rated into the 400 degree mark. You will not get failure as long as you put liquid in when heating. The water prevents the o-rings from getting much over 200 degrees.