Teflon tape a no no?

[MikeD74T]

Thread sealing is more complex than teflon tape vs pipe dope. Look at the Loctite PST pages. Various PST compounds are used widely in the nuclear industry. You get what you pay for in leak prevention. MikeD74T

 

[Wayne County Hose]

At about 20 hrs I had a leak on the fel. Instead of taking it to the dealer I just re-taped it myself. I no I didn't start a thread back, as a matter of fact I'm sure I started at the tip.

I changed the fluid at the 50hr mark and now I'm at 80 and am wondering if I should back the fitting out and tape it the right way. Easy to do, but with my luck I'll end up cross threading the fitting.

So, if the tape was to get into the system wouldn't it have done it by now, or should I re-tape it???

I wouldn't worry about it.

 

[Wayne County Hose]

Thread sealing is more complex than teflon tape vs pipe dope. Look at the Loctite PST pages. Various PST compounds are used widely in the nuclear industry. You get what you pay for in leak prevention. MikeD74T

Boy, if they are using NPT to seal nuclear stuff, we're in trouble. NPT is the absolute least reliable fitting there is.

 

[canoetrpr]

Excellent thread and timely for me.

I've got most of my fittings and hoses and I'm ready to install my new remote valve. I have the odd NTP fitting though I've tried to avoid it. WCH spent some time very early on educating me on the advantages of JIC and ORB so most of what I have is that.

The local hydraulics shop that made my hoses and sold me my fittings handed me the yellow telfon tape for sealing the male NTP fittings that I have.

Do I have this right. To use the the tape properly:
- No more than 2 times around the threads.
- Leave at least one thread at the bottom exposed?

Is that it or is there some more technique to it that I am missing?

Do I just tear the tape with my fingers or use a blade or something?

Apologize if this sounds stupid... just want to get this right.

 

[Wayne County Hose]

Doesn't sound stupid at all. I think it's rather smart to ask and get it right the first time. I don't use teflon, but from what has been successful for most here, that sounds about right. Just remember not to use any thread sealer on an NPT swivel fitting. These are easily identified by the female end. If you look in the female end and see a cone inside, it's a swivel fitting. NPT has 2 types of sealing surfaces, internal cone and external thread. If it seals on the cone, no sealant. Look straight into the male end. You will see a 45 degree taper. This is what seals in the internal NPT fitting, not the thread.

 

[canoetrpr]

Hmm. I thought an NTP swivel fitting would be a female end that actually swivels... is this not the case?

Pretty sure that I all I have are non swivels. I've got one JIC by NTP male by male fitting to get my return hose to the tack to fit the Kubota port plug which is a plain ol NTP female.

Then I have male ORB (valve ports) by male NTP that fit into a 45 degree female NTP by male NTP - which go into NTP QDs.

 

[MikeD74T]

Boy, if they are using NPT to seal nuclear stuff, we're in trouble. NPT is the absolute least reliable fitting there is.

Then I guess we're in trouble !!!!! MikeD74T

 

[Wayne County Hose]

Hmm. I thought an NTP swivel fitting would be a female end that actually swivels... is this not the case?

Pretty sure that I all I have are non swivels. I've got one JIC by NTP male by male fitting to get my return hose to the tack to fit the Kubota port plug which is a plain ol NTP female.

Then I have male ORB (valve ports) by male NTP that fit into a 45 degree female NTP by male NTP - which go into NTP QDs.

Sorry for any confusion, I have 2 brain cells left and some days they don't speak to each other.
An NPT swivel looks like a female JIC fitting, except that the cone faces out on the NPT and in on the JIC.

 

[SPYDERLK]

Excellent thread and timely for me.

I've got most of my fittings and hoses and I'm ready to install my new remote valve. I have the odd NTP fitting though I've tried to avoid it. WCH spent some time very early on educating me on the advantages of JIC and ORB so most of what I have is that.

The local hydraulics shop that made my hoses and sold me my fittings handed me the yellow telfon tape for sealing the male NTP fittings that I have.

Do I have this right. To use the the tape properly:
- No more than 2 times around the threads.
- Leave at least one thread at the bottom exposed?

Is that it or is there some more technique to it that I am missing?

Do I just tear the tape with my fingers or use a blade or something?

Apologize if this sounds stupid... just want to get this right.

Good question. There is a little more:

1. Theres a decision point based on experience about tape thickness vs number of wraps vs quality of the fit between joint members. Some of the cheapo tapes are thin and might deserve more wraps. Of course it is the thickness of tape buildup that is the issue factoring in fit quality. On a new tight joint 2 wraps of even the thin stuff is sufficient. With a sloppier joint, as usual, I put the 1st wrap one thread up and then spiral up to the next thread on the 2nd and maybe 3rd wrap - then up again for a 4th if it seems that the joint must be engaged deeply to tighten.

2. Always wrap in the direction that the thread progresses. That avoids any tendency the tape may have to unwind as the thread engages.

3. Pull the tape snug into the threads as you wind. When thru just pull to break the tape where you decide youve got it wrapped.

4. As Andy, WCH, says - no tape in a swivel joint. Yould just be wasting it since the threads dont tighten - they just drive the sealing cone tapers together. Oil on the fitting parts is a real good choice there.

larry

 

[Skyco]

Teflon tape on pipe thread? <shrug> my Kubota came from the factory with it on every NPT fitting........
Works for me