NPTF fitting/port question
NPTF fitting/port question
(OP)
I have an application where we currently thread a steel NPT plug into an aluminum housing. I am looking to change both parts from NPT to NPTF to avoid having to apply Teflon tape (this is a production part and would save assembly time). From the other research I have done, the NPTF thread should create a good seal without the Teflon tape, as the parts are designed to deform together. My worry is that while the aluminum part will deform correctly, the steel won't. That would still leave one spiral leak path and we will end up having to use the Teflon tape anyway. Also, I have seen comments that NPTF should still use the Teflon tape to avoid galling at installation. I was hoping to be able to use a spray-on lubricant to avoid the galling. Does anyone have experience with either of these issues? Thanks!





RE: NPTF fitting/port question
RE: NPTF fitting/port question
Ted
RE: NPTF fitting/port question
RE: NPTF fitting/port question
If you used o-ring ports, you could use different adapters for each order, and eliminate the extra holes and plugs.
Mike Halloran
Pembroke Pines, FL, USA
RE: NPTF fitting/port question
RE: NPTF fitting/port question
Maybe that is an "old wives' tale" or "industrial folklore" I've picked up somewhere along the way.
RE: NPTF fitting/port question
RE: NPTF fitting/port question
RE: NPTF fitting/port question
Ted
RE: NPTF fitting/port question
RE: NPTF fitting/port question
Using threaded joints without a gasket/o-ring or sealant is a different matter and is usually a bad idea.
RE: NPTF fitting/port question
Ted
RE: NPTF fitting/port question
RE: NPTF fitting/port question
In a service with any significant amount of water INSIDE the system, or where the system is immersed externally, I wouldn't use a steel plug in an aluminum component! So yes, the success of this pairing of materials DOES depend on service. And without a gasket or sealant in an NPT joint of any design- forget about it!
RE: NPTF fitting/port question
RE: NPTF fitting/port question
Link:
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RE: NPTF fitting/port question
I like PTFE based seal tape and prevent any from hanging over the edge. One tape issue is leaving fragments that can blow down the tubing etc.
Some thread seals are listed and colored for different applications. Potable water should be different than other water or gas applicatons to accommodate plumbing inspection. The PTFE temperature limit below about 300 degree F would not suit some other applications. Some sealants permit easy removal and others are nearly permanant. Some thread paste is like pipe dope; others not.
I don't remember using a spray by intention although even WD-40 etc. could happen in a pinch. Use good judgement along with supplier documentation to obtain a good fit.