What Gasket material makes the best seal?

[SamuraiSam]

@pangea

Kalrez over Tuf-Steel?

edit: damn Its been a minute since I checked the prices. I thought the $300 for kalrez was a 12"… jesus they are expensive, fucking 4"…

that’s insane…

@SidViscous

I prefer the lower durometer. I honestly have no tuf-steel experience but sounds like it’s pretty much just reinforced PTFE.

That’s exactly what it is, sintered “Passivated and atomized” stainless steel impregnated PTFE. In my limited experience, it’s so stiff that it doesn’t seal well enough to allow full vacuum depth, just like plain PTFE. I also prefer lower durometer gaskets; don’t trust stiff ones to seal dinged up tri clamp flanges well at -30"Hg or 100+psi

@TheGratefulPhil

I think Buna-N is a bad choice given its limited chemical compatability.

Next step up would be FKM.

Ideally, PTFE envelope gaskets—but be warned, they require a lot more torque to seal properly. My suggestion is that you purchase a torque wrench and torque the bolts down to the same value each time you tighten.

Tufsteel is really stiff, like unforgivingly stiff. It seems to have the best temperature rating and chemical compatibility, but I’ve only ever used it for steam service.

Same thoughts on buna-n; I use alcohol to clean oil residues off surfaces, and you see the buna breaking down if you use white rags. If it comes off on a rag it could come off into the oil. So. FKM for me.