Loctite 577 Thread Sealer question

[Submariner1]

If you use ptfe again. Put more of it on. You’re not using enough! It’s very thin and has to fill all the imperfections between the two threads.

I tried 12 layers on one joint and was gobsmacked it still leaked albeit a very small leak. It needed and extra 1/8 turn to seal it.
Hence gave up on this - note all new fittings in SS.
Weird as I have never had problems sealing pipes with ptfe tape before , but then they were not running 150 psi.

 

[Turbo]

To those who suggest putting on loads of PTFE tape - its the wrong way to use it!

PTFE tape is used as a lubricant to allow you to tighten taper threaded fittings tight enough so they seal! It is not a sealant so putting on loads of it will not help a bad joint stop leaking - it can make it worse by stopping you being able to tighten the joint fully! All you need on a taper fit joint is 2 or 3 layers of tape on all the threads. It rarely works on parallel thread fittings!

 

[waddycall]

I disagree with that. I’m a heating engineer and use both ptfe and loctite 55 daily on water, gas and oil. The quality of many pipe fittings is pretty poor and often requires more than the “correct” amount of tape/loctite/sealant. I also use mixtures of ptfe and paste and loctite 55 and paste which is also considered wrong. And I also use non gas rated ptfe on gas fittings when necessary.
It’s very difficult to buy taper thread male irons these days for some reason. They often end up with a washer and tape and sealant!
The welder/pipe fitter on our firm uses 20 wraps of ptfe on larger pipe sizes.!
I also don’t know anyone who hand tightens and then counts the turns to determine if a fittings done up properly.

 

[Ross365]

Yes, I too regard PTFE tape as both a lube and a sealant, primarily on tapered fittings. I've used it successfully with some hellishly reactive chemicals. The problem is now that there is some really poor "PTFE" tape around. Good PTFE tape is really soft and compliant, the cheap versions are not pure PTFE, they are co-polymers and are not really as good as the real stuff and just feels "wrong".

 

[Submariner1]

If you use ptfe again. Put more of it on. You’re not using enough! It’s very thin and has to fill all the imperfections between the two threads.

well I had success with Loctite 577. Only issue was one joint where to get the angle right I had to back it off 1/2 revolution and that one had a tiny leak. Actually locked up the joint hand tight plus a tad with a spanner, and set with Loctite 577 and then cut off the ears on the O clamps and reset the angle where the hose-tail went into the hose. Bit of a pain. But now all are perfectly air tight.
Lesson learnt. Think ahead LOL!
Going into the air-filter one had to be just hand tight, to get the right angle. And Loctite 577 sealed it perfectly.

 

[paroczaiz]

I had the same issue once, the Loctite 577 solved it