Female PTFE to male glass - best way to seal?


I have a slightly different setup from the standard full bore short path since I am rocking a stainless steel cold trap.

I ended up grabbing one of these female PTFE adapters and I was wondering how to make sure it’s nice and sealed, as the adapters seem slightly lose. Just grease or distillate?

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Usually there is a sealing ring?

Like the ones from Beaker and Wrench

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It has a seal ring, it just doesn’t have the best fit


Normal ptfe is inherently a product that has memory. You get less uses from them and should use a very expensive grease. And never Mar the sides. If it fits loosely it means who ever sold you the PTFE had them in large bags, the the heaver ones at top squished the ones on bottom and they aren’t true. Send then back to avoid inherent leaks.


I feel that this is the leak point on my new setup that I have pieced together. Just gotta figure out a good way to diagnose it.

I picked up the PTFE from beaker and wrench and I’m using KF25 and 1" steel pipe from the PTFE to the cold trap and to the pump. Still need a few more pieces before I am happy, but it is running

Much love for the glassware, just trying to get it working at peak performance

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String, zip tie, lab stand to relieve the weight of the bellows at the joint.?