PTFE vs. TFE

[teg]

I'm thinking I'm going to install hydraulics with TFE... all it says is "Do not use on halogens..." I'm using Harvey's TFE paste which is good for 10,000 psi on use for water, steam, natural & LP gas, *OILS*, fuels & dilute acids. Do I have to use PTFE???

And just in case, What will happen if I use it???

 

[kennyd]

Got me...

 

[slowzuki]

TFE is PTFE - Poly tetra fluoro ethylene - aka teflon

Its akin to Polyethylene plastic, poly just means many molecules of ethylene chained.

You couldn't use your sealant with some refrigerants or the oil containing part of said refrigeration system.

 

[teg]

Cool thanks...

I Google Halogens... comprising fluorine (F), chlorine (Cl), bromine (Br), iodine (I), and astatine (At). So I'll continue to assume this paste will work since Oil was listed...

Photo of the pipe thread compound and the spool location. I was planning to use fittings to plumb... :mur: I will be get a couple of extra hoses in the morning :ashamed::confused2::confused2:

 

[Ford tractor]

Cool thanks...

I Google Halogens... comprising fluorine (F), chlorine (Cl), bromine (Br), iodine (I), and astatine (At). So I'll continue to assume this paste will work since Oil was listed...

Photo of the pipe thread compound and the spool location. I was planning to use fittings to plumb... :mur: I will be get a couple of extra hoses in the morning :ashamed::confused2::confused2:

Uh.... you do know that you plumb hydraulic fittings DRY, right? No goop, no tape. Just clean, dry fittings torqued to spec.

Unless you WANT to bugger up the entire system when that stuff gets into it.

 

[CurlyDave]

The paste is good.

Slowzuki is right, PTFE and TFE are the same stuff, and you have no halogens in your hydraulic system.

If you have pipe threads in your system you need pipe thread sealant on only those fittings. Other types of fitting do not require sealant.

 

[teg]

Uh.... you do know that you plumb hydraulic fittings DRY, right? No goop, no tape. Just clean, dry fittings torqued to spec.

Unless you WANT to bugger up the entire system when that stuff gets into it.

Are you saying that NPT is done dry? or are you talking about the other types??? I didn't want ANY leaks so I used the paste on the NPT connections.

Can you explain a little more about "...bugger up the entire system..." What exactly would getting some of this paste mixed up in say the 5-6 gallons that my system uses. I would like to know if I need to change the hydraulic oil since I'm sure a little bit might have gotten in there.

 

[kennyd]

Are you saying that NPT is done dry? or are you talking about the other types??? I didn't want ANY leaks so I used the paste on the NPT connections.

Can you explain a little more about "...bugger up the entire system..." What exactly would getting some of this paste mixed up in say the 5-6 gallons that my system uses. I would like to know if I need to change the hydraulic oil since I'm sure a little bit might have gotten in there.

You have nothing to worry about:thumbsup:

 

[kennyd]

Uh.... you do know that you plumb hydraulic fittings DRY, right? No goop, no tape. Just clean, dry fittings torqued to spec.

Unless you WANT to bugger up the entire system when that stuff gets into it.

Like others...I would like you to explain this a little better please.:confused2:

 

[Discount Hydraulic Hose]

Are you saying that NPT is done dry? or are you talking about the other types??? I didn't want ANY leaks so I used the paste on the NPT connections.

Can you explain a little more about "...bugger up the entire system..." What exactly would getting some of this paste mixed up in say the 5-6 gallons that my system uses. I would like to know if I need to change the hydraulic oil since I'm sure a little bit might have gotten in there.

NPT (National Pipe Thread) requires thread sealant.

However, most hydraulic fittings are actually NPTF (National Pipe Tapered Fuel), also called Dryseal American National Standard Taper Pipe Thread, defined by ANSI B1.20.3.

NPTF is designed to provide a more leak-free seal without the use of teflon tape or other sealant compound. NPTF threads are the same basic shape but with crest and root heights adjusted for an interference fit, eliminating the spiral leakage path.

source: National pipe thread - Wikipedia, the free encyclopedia

NPTF fittings will mate with same-size NPT fittings, and can be used in all applications calling for NPT.

IMPORTANT: Because the threads are deformed when fittings are assembled, an NPTF connection may not seal as intended (without sealant) after it has been disassembled and assembled again. In this instance, the use of tape or paste should create an effective seal.

Another useful description of NPT and NPTF threads can be found here

 

[teg]

OH, goodie... more acronyms :confused2:

:thumbsup::thumbsup::thumbsup: Thanks for the good information.... and yes, I had to redo some of my connections to be able to make other connections work. I also, reversed the high pressure return with the low pressure return... lucky I figured that one out before hooking up the hoses... caught it during one of my many "follow the hoses" checks.

 

[slowzuki]

As a note for others looking at this thread in the future, never use teflon tape in any threads on a hydraulic system. The stringing bits of it can get inside and get stuck inside important parts of the hydraulic system. The liquid pipe dopes (most of them anyways) won't harden in oil so they just get mixed in, preventing a clogging problem.

 

[kennyd]

As a note for others looking at this thread in the future, never use teflon tape in any threads on a hydraulic system. The stringing bits of it can get inside and get stuck inside important parts of the hydraulic system. The liquid pipe dopes (most of them anyways) won't harden in oil so they just get mixed in, preventing a clogging problem.

That great advice falls on many deaf ears 'round here:thumbsup: There have recently been several threads dedicated to that very subject.

 

[Ford tractor]

Are you saying that NPT is done dry? or are you talking about the other types??? I didn't want ANY leaks so I used the paste on the NPT connections.

Can you explain a little more about "...bugger up the entire system..." What exactly would getting some of this paste mixed up in say the 5-6 gallons that my system uses. I would like to know if I need to change the hydraulic oil since I'm sure a little bit might have gotten in there.

Sorry to have posted and run, but you know how it goes some days.

NPT pipe fittings like from the hardware store are used on low pressure systems. The technical discussion occurred without me (and far better than I could do it too!). Basically, real hydraulic fittings are engineered to be assembled dry and they will stay that way when correctly torqued. Too loose and too tight are equally bad by the way.

If you've ever plumbed up stuff in the house and found the stringy PTFE tape or gobs of the paste in the faucet screen you know that stuff does not stay put. Running it through hydraulic pumps and valves that may have clearances in the millionth's of an inch isn't good. Odd as it may seem, there are worse things (and more expensive overall) than a moist fitting.

Just my $0.02 including tax. Take it or leave it as you see fit.

 

[teg]

It'll take it!!! It's *ALL* good information... By the way the whole write up of the finish spool is at the link below... I put it in the kubota section mainly because it's about one of those models (hindsight, should have posted in hydraulics)

http://www.tractorbynet.com/forums/...7948-instructions-add-extra-spools-l2800.html

Thanks again... Dan/teg

 

[SpringHollow]

Unfortunately, there are still a lot of NPT fittings on many of our hydraulic systems and they require sealant. I have switched a few over on mine but that is really long term thinking since the adapter i need to use is still NPT so it only helps me when i change the hose the next time. For really clean fittings, there are liquid sealants that can be used. But most hose repairs are not done in such clean conditions. So we have to use paste or tape. Lots of factory hydraulic items are done with tape. Either product causes a problem if done wrong.

Ken