Tape or Paste fittings

[C4Ranch]

What do you do?

I read here that many prefer paste but for the life of me, I seem to have many of them leak when I paste...

 

[oldnslo]

Teflon tape is fine as long as you don't wrap the first couple of threads. Typically the problem with tape is when you take fittings apart and the tape strings get left in the fittings.

 

[Furu]

Since this is in the hydraulic forum I presume you mean hydraulic fittings. I use tape all the time on water/air pipe threads.

Many folks believe, quite correctly, that tape can find its way into the pump and filter and really gum up the works. Paste does not do that as it does not have what amounts to the filament threads. I believe that an argument can be made that tape is just fine but if not installed very carefully and more importantly IMO, when the fitting is removed you have to be very careful to not leave any of the remnants so that they can get down into the fluid and find their way to the pump/filter. Not always possible or easy.
The only time I have had paste leak was when the thread had minor damage to it and in a 2800-3000 psi system that needed to be replaced anyway.

Best idea is to not use NPT fittings and the problem goes away. JIC, ORB, ORFS are far superior in just about every way.

 

[mfreund]

Do not use tape on hydraulic fitting. Any tape loose will plug the filters and get stuck in the valves.

 

[/pine]

Lots of threads/arguments on this subject...
This argument can go either way...paste almost always has to allowed to cure before introducing pressure...

most of the issues come from "re-work" i.e., if you remove a taped fitting you have to be careful to get all the old tape out of the threads...but the same goes for paste which can actually be harder to remove without letting some chunks fall deeper into whatever the fitting is on...

Even professional (Goodyear) hydraulic shops use and sell tape (and paste)...

The ultimate argument for not using tape is that there is a story out there where tape was supposedly found to be the cause of an airplane crashing because the hydraulics were clogged by tape...

IMO prudent/judicial use of tape is better than sloppy use of paste...and much easier to re-work...

 

[J_J]

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.

 

[/pine]

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.

Actually I read about the aircraft issue in another thread here on TBN...

According to many manufacturers Teflon tape is "only a lubricant" and not a sealant...and this makes sense why it works well with NTP...:thumbsup:

 

[SPYDERLK]

Actually I read about the aircraft issue in another thread here on TBN...

According to many manufacturers Teflon tape is "only a lubricant" and not a sealant...and this makes sense why it works well with NTP...:thumbsup:

I would have some fun with anybody that fed me that line.

 

[varmint]

Ah... a brother manufactures specialty valves and pump units for the geothermal industry... he still makes some with threads, only because some customers demand them, but the great majority use simple o-ring press seals. The threaded valves greatly outnumber the o-ringed for leakage issues, although they are only a tiny fraction of the total.

 

[Deere Dude]

For me tape is least preferred and Teflon paste is good stuff, but for fewer leaks I use LocTite 242 I believe the number is. The blue stuff. That hardly ever leaks with pipe and I have had no problem getting fittings apart. This is a thread-locker that works great for bolts and nuts so they don't vibrate loose also.


Hydraulic systems use a different number of LockTite from the same company.

 

[BukitCase]

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]

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]

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]

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]

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]

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]

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

 

[bigdeano]

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]

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]

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.