Anyone got any tips for removing teflon seal tape?

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Anyone got any tips for removing teflon seal tape?

Postby chrismb » Tue Jan 18, 2011 4:46 pm

In the last few weeks I have spent some not-inconsiderable time trying to buy connectors for, and then connect, my various gas sources to my vacuum system. It's been a minor UNF/UNEF/NPT/NPTF/BSPP/BSPT-adapter-nipple-plug'n'cap-reducer nightmare!

After finding out one of my two regulators leaked across the valve, and the other [which I knew] is a bit low and can't use it for all gases, fortunately the god of ebay offered me a multi-stage 300-down-to-10 bar regulator, specifically for flammable gases. Perfect... now some more thread sizes to find... (who the h*ll uses 1/2" UNEF!?!?).

Anyhows, in fiddling towards the optimum configuration, removal and refitting of components is the norm. But I have yet to develop a good and effective method of cleaning off used teflon tape off of threads. It's pick-pick-pick-pick, whilst all the little bits static-cling to your fingers and you can't brush them off! ....

Any tips?.....
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Re: Anyone got any tips for removing teflon seal tape?

Postby Doug Coulter » Tue Jan 18, 2011 5:34 pm

Being also a guitar player, I have fingernails on one hand. I insert a good one into the thread, and simply screw the stuff off by following a thread bottom with it under pressure as I turn the fitting. Anything more brutal than that risks scratching the threads along the leak paths. Gets it done pretty quick, and usually if you don't quite get it all, it's better, not worse. If it's that far dug into pits, better to leave them full.

Having said that, you can't use tape (or residue) to correct for a lot of "bent" -- or scored, either.
That has to be fixed separately.

Having said that, just a dumb observation. I "just knew" that someday being a computer guy would mean I didn't have to crawl on floors (or even under them, in the day). Or that being a physicist meant I could ditch the art of plumbing. In some senses, being able to do both of those is critical to success. Rats! Foiled again! And the fittings eat your budget, unless you design with as few as possible and make those if you can.

Can you tell? I'm fighting a new leak around my ion source these days, and it's in a hard place to work on. Sigh.
Posting as just me, not as the forum owner. Everything I say is "in my opinion" and YMMV -- which should go for everyone without saying.
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Re: Anyone got any tips for removing teflon seal tape?

Postby chrismb » Tue Jan 18, 2011 6:02 pm

Doug Coulter wrote: And the fittings eat your budget, unless you design with as few as possible and make those if you can.
I have been investing far too much time trawling the internet for the best deals, to avoid exactly that! Of course, you can't just look for the best deal on 'one fitting' because you have to pick a set which go together. I think it would've been much cheaper for me just to buy all options straight off, at the best price to find. But I guess I've spend >10 hours or so picking gas fittings that have cost me £100, rather than £200 the 'dumb' way. Sometimes the money-time trade off works for you, sometimes against.... sometimes you're so tired from trying to keep costs down that you can no longer tell!

I now have a few different ways to set it all up, depending on the bottle-source.

One other thing I'd like to get some confidence on - the most 'geometrically satisfying' way for me to handle one gas with my fittings, at 100 bar, is to take it through a 1/8 npt. I kinda get the feeling that it's a small fitting to take that load (which'd be some 70kg on the threads). Obviously I'd try to squeeze out less than that on the bottle tap, but my Q is; are 1/8" npt brass fittings OK for 100 bar? [I've seen some rated to 3000psi, so I presume that it is OK, but this is a 'lego set' of connectors and any confidence-building tips/warnings welcome!]
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