Tape or Paste fittings

BukitCase · Jul 22, 2014

I use the actual hydraulic thread sealant on fittings where I have no choice but deal with NPT, it's Loctite 545 - they also make a quick set version that's about 4 times as fast, it's Loctite 5452.

Use a lot of the 242 - but be careful, it's supposedly "removable", but if you read the fine print it's removable on 1/4" and BIGGER - use it on a 8-32 screw, and odds are you'll be DRILLING it out... Steve

SPYDERLK · Jul 23, 2014

BukitCase said:
Use a lot of the 242 - but be careful, it's supposedly "removable", but if you read the fine print it's removable on 1/4" and BIGGER - use it on a 8-32 screw, and odds are you'll be DRILLING it out... Steve

Warm it up. 242 weakens fast. It is only half as strong when it gets up to 212F.
larry

5030 · Jul 23, 2014

J_J said:
I am not sure that any aircraft uses NPT fittings, and therefore no tape required.

In the normal sense of things, only NPT threads use tape with discretion.

Not all NPT threads require sealing tape or paste. If it's a dryseal NPT thread, no dealant is required.

Winmac · Jul 23, 2014

My preference is paste but I've run across some very poorly cut threads that nothing would seal.

Instead or being round the thread portion was distorted into a triangular shape. Junk...

SPYDERLK · Jul 23, 2014

Winmac said:
My preference is paste but I've run across some very poorly cut threads that nothing would seal.

Instead or being round the thread portion was distorted into a triangular shape. Junk...

A bad run of Chinese crap. Probably could chase em with a Chinese die. Its a conspiracy no doubt.

,,,,Actually, I would bet on loctite and extreme tightening to work. :confused3:
larry

nybirdman · Jul 23, 2014

As a pipefitter/steamfitter for 42 years.First,the tape,pipe dope is really only a lubricant ,the threads are what make the leak free connection.We were required to use only liquid pipe dope on hydraulics.The influx of cheap Chinese fittings has caused the industry great grief.
A lot of life long plumbers/pipefitters will disagree with my statement;but I had 25 years on construction and 17 in an auto plant;instructor for for journeymen and apprentices and nuclear certified welder.

batwing · Jul 23, 2014

I have best luck using both tape and paste, my real problem is over tightening.
Ron

bigdeano · Jul 23, 2014

I use LocTite 242 on new clean threads. Repairing something that's all oily I use teflon tape. Any kind of paste that hasn't hardened will push right out under hydraulic pressures in my experience. I've stopped a lot of leaks in water pipes with teflon tape, but occasionally it will still leak. You sometimes have to put more or fewer layers on.

Gary Fowler · Jul 23, 2014

batwing said:
I have best luck using both tape and paste, my real problem is over tightening.
Ron

I would agree that overtightening causes as many leaks as bad threads. Good threads become bad when tightened too much. Also most pipe dope is just a lubricant so you can tighten without galling the threads.

The most laughed at situation is someone putting Teflon tape on high pressure cylinder gauges thinking the threads seal.

jcummins · Jul 23, 2014

I had trouble with a leaking shower facuet i install. Tape did not work. It was the sloppiness in the threads and a plumbing house said use Real-Tuff... I did it worked very well. I'm now using on hydraulic fitting that require it.... And i like it.