I read somewhere that it's not a good idea to uses Teflon tape on threaded
joints in a hydraulic system.
Is that correct and if so, why?

Is it because tape can break off & clog the orifices, or, is it because
hydraulic fluid dissolves Teflon? (it seems to) ...... or are there other
reasons?
Pipe threading compound contains Teflon.
I'm wondering if I should take all those fittings apart and replace the
tape.
TIA

larsen-tools wrote:

I read somewhere that it's not a good idea to uses Teflon tape on threaded
joints in a hydraulic system.
Is that correct and if so, why?

Is it because tape can break off & clog the orifices, or, is it because
hydraulic fluid dissolves Teflon? (it seems to) ...... or are there other
reasons?
Pipe threading compound contains Teflon.
I'm wondering if I should take all those fittings apart and replace the
tape.
TIA

Teflon is bad in light airplane fuel systems--(gravity feed, no fuel pump)
because a little sliver can stop up the main jet or needle valve----if you
tape too close to the end of the male fitting, it can sometimes squeeze ahead
& cut itself loose to wander
around

I wouldn't worry about a hydraulic system, they usually have filters & a few
passes thru the pump will chop it down fine.---unless you have some pilot
operated
flow control valves with leetle bitty oryfices...The thread joint compounds
with
Teflon usualy have the TFE ground up very fine to obviate such circumstances.

p.s.I dunno ANYTHING that will dissolve tetra flouro eththylene.

larsen-tools wrote:

I read somewhere that it's not a good idea to uses Teflon tape on threaded
joints in a hydraulic system.
Is that correct and if so, why?

Is it because tape can break off & clog the orifices, or, is it because
hydraulic fluid dissolves Teflon? (it seems to) ...... or are there other
reasons?
Pipe threading compound contains Teflon.
I'm wondering if I should take all those fittings apart and replace the
tape.
TIA

In article 586uc.17891$mm1.12389@fed1read06,
"larsen-tools" wrote:

I read somewhere that it's not a good idea to uses Teflon tape on threaded
joints in a hydraulic system.
Is that correct and if so, why?

If you did a hack job of it and stretched tape across the openings, I
could see shreds of tape getting into the fluid stream, and perhaps
sticking in valve ports, etc. If you did a proper job it should do
nothing of the sort. You would want to be careful to get it all out when
removing fittings, as that would be a point where carelessness might
result in shreds going into the system.

I expect that you can read somewhere that it's bad, and you can read
somewhere else that it's good. If the system is assembled and has been
run, there's no benefit to dissasembly now, IMHO. Any shreds that are
likely to get in the fluid stream have probably done so, and they will
either end up in the filter eventually and cause no problems, or they
will end up somewhere that causes a problem.

That said, I'll also note that on _my_ hydraulic system, there are no
places teflon tape or pipe dope make any sense at all, as far as I
recall. All the connections I've had to open up are sealed either with
o-rings, or flare fittings - the threads just bring the sealing surfaces
together. Pipe dope might serve as anti-seize, which is no bad thing
(some of my connections took two 3-ft wrenches to open up after being
connected for up to 34 years), but anti-sieze will work just as well.
Your system may well differ and have pipe threads sealing connections.

--
Cats, Coffee, Chocolate...vices to live by

Thanks guys.
I've been reading a lot about home build airplanes (RV-7A to be specific)
and that's where I got the idea that Teflon tape was bad...... now I get it
........... in fuel systems.
What a relief....... I envisioned the hydraulic wonder I'm making working
only when it felt like it....... thanks to the Teflon tape.

"larsen-tools" wrote in message
news:586uc.17891$mm1.12389@fed1read06...
I read somewhere that it's not a good idea to uses Teflon tape on threaded
joints in a hydraulic system.
Is that correct and if so, why?

Is it because tape can break off & clog the orifices, or, is it because
hydraulic fluid dissolves Teflon? (it seems to) ...... or are there other
reasons?
Pipe threading compound contains Teflon.
I'm wondering if I should take all those fittings apart and replace the
tape.
TIA

"Ecnerwal" wrote in message
...
In article 586uc.17891$mm1.12389@fed1read06,


SNIP
That said, I'll also note that on _my_ hydraulic system, there are no
places teflon tape or pipe dope make any sense at all, as far as I
recall. All the connections I've had to open up are sealed either with
o-rings, or flare fittings - the threads just bring the sealing surfaces
together. Pipe dope might serve as anti-seize, which is no bad thing
(some of my connections took two 3-ft wrenches to open up after being
connected for up to 34 years), but anti-sieze will work just as well.
Your system may well differ and have pipe threads sealing connections.

--
Cats, Coffee, Chocolate...vices to live by
The above says a lot. Are you working a hydraulic system that is using pipe
thread? If using pipe thread then Teflon, properly applied is fine. If
your using any other type of fitting then Teflon is not the stuff to use.
Teflon tape is designed as a LUBRICANT so that tapered pipe fittings can be
tightened correctly without galling. It is not a sealant!

larsen-tools wrote:

I read somewhere that it's not a good idea to uses Teflon tape on threaded
joints in a hydraulic system.

As I understand it, the TFE "problem" is fine shreds of TFE getting into
the system snd clogging fine jets (e.g. diesel injectors). If properly
applied to pipe threads, it's fine. "Properly applied" means the tape
does not cover or extend beyond the last male thread. I think the
"don't use" mandate is because you can't count on the ham fisted
properly applying it.

Ted

jerry Wass wrote:
p.s.I dunno ANYTHING that will dissolve tetra flouro eththylene.


Hot acids will.

How many wraps is "properly applied?


"Ted Edwards" wrote in message
...
larsen-tools wrote:

I read somewhere that it's not a good idea to uses Teflon tape on
threaded
joints in a hydraulic system.

As I understand it, the TFE "problem" is fine shreds of TFE getting into
the system snd clogging fine jets (e.g. diesel injectors). If properly
applied to pipe threads, it's fine. "Properly applied" means the tape
does not cover or extend beyond the last male thread. I think the
"don't use" mandate is because you can't count on the ham fisted
properly applying it.

Ted

On Sun, 30 May 2004 17:33:39 GMT, Ted Edwards
wrote:

larsen-tools wrote:

I read somewhere that it's not a good idea to uses Teflon tape on threaded
joints in a hydraulic system.

As I understand it, the TFE "problem" is fine shreds of TFE getting into
the system snd clogging fine jets (e.g. diesel injectors). If properly
applied to pipe threads, it's fine. "Properly applied" means the tape
does not cover or extend beyond the last male thread. I think the
"don't use" mandate is because you can't count on the ham fisted
properly applying it.

Ted


I once set up a hydraulic system to drive a very small servo valve
controlling a roller position within very few thousandths. Tiny
orifices in that thing, and it was very expensive. The plumbing was
mostly mechanical tubing, with very few tapered thread fittings. We
used a hardening Loctite product designed to seal hydraulic systems on
those. The servo valve, manifold mounted, came with a flushing
fitting to allow startup and circulation through the filters for a day
before changing the filters and installing the valve. The
commissioning instructions were full of cautions about maintaining
near clean-room conditions while the system was open.

I suspect there'd be a lot more forgiveness in hydraulics on a backhoe
or something similar.

Pete Keillor

On Sat, 29 May 2004 12:09:24 -0700, "larsen-tools"
wrote:

I read somewhere that it's not a good idea to uses Teflon tape on threaded
joints in a hydraulic system.
Is that correct and if so, why?
It is best not to use Teflon tape as it can shred and clog parts of
your system - a problem you will not encounter with Pipe Sealer with
Teflon. Another problem I recall was in a plant here in Houston years
ago when Teflon tape was used in fittings on a fuel loading hose.
Apparently, the tape was thick enough to act as an insulator and
allowed static electricity to build rather than discharge to ground.
When the operator touched the nozzle to the lip of the filler a spark
ignited the gasoline.

On Mon, 31 May 2004 02:45:22 GMT, (Tom)
wrote:

On Sat, 29 May 2004 12:09:24 -0700, "larsen-tools"
wrote:

I read somewhere that it's not a good idea to uses Teflon tape on threaded
joints in a hydraulic system.
Is that correct and if so, why?
It is best not to use Teflon tape as it can shred and clog parts of
your system - a problem you will not encounter with Pipe Sealer with
Teflon. Another problem I recall was in a plant here in Houston years
ago when Teflon tape was used in fittings on a fuel loading hose.
Apparently, the tape was thick enough to act as an insulator and
allowed static electricity to build rather than discharge to ground.
When the operator touched the nozzle to the lip of the filler a spark
ignited the gasoline.

Definitely a no-no on fuel dipensing equipment (although you see it
all the time) or natural gas/propane systems, it is also dangerous in
fuel systems and hydraulics. It CAN be applied in a safe manner, but
it is extremely difficult to know if it is actually safe after it is
installed, as far as shredding is concerned, and is virtually never
checked as far as ground continuity.

"Tom" wrote in message
...
On Sat, 29 May 2004 12:09:24 -0700, "larsen-tools"
wrote:

I read somewhere that it's not a good idea to uses Teflon tape on
threaded
joints in a hydraulic system.
Is that correct and if so, why?
It is best not to use Teflon tape as it can shred and clog parts of
your system - a problem you will not encounter with Pipe Sealer with
Teflon. Another problem I recall was in a plant here in Houston years
ago when Teflon tape was used in fittings on a fuel loading hose.
Apparently, the tape was thick enough to act as an insulator and
allowed static electricity to build rather than discharge to ground.
When the operator touched the nozzle to the lip of the filler a spark
ignited the gasoline.
AHAA!! - So that's why 'they' made me get that expensive thread sealer for
the fuel delivery system at the golf course shop. Live and learn - ain't
life wonderful.
Regards.
Ken.

clogging of orfices, and that most hydraulaics are sealed w/ 37°, 45° or
other angle faces, or O-rings against bosses/c-bores, not the threads so do
not nead a sealant, though NPT fittings do. Same is true for heating oil
lines/fittings. The Teflon does not dissolve in oil (or much of anything)
but it doesn't seal oil well either, so tapered thread fittings tend to
seep.

"larsen-tools" wrote in message
news:586uc.17891$mm1.12389@fed1read06...
I read somewhere that it's not a good idea to uses Teflon tape on threaded
joints in a hydraulic system.
Is that correct and if so, why?

Is it because tape can break off & clog the orifices, or, is it because
hydraulic fluid dissolves Teflon? (it seems to) ...... or are there other
reasons?
Pipe threading compound contains Teflon.
I'm wondering if I should take all those fittings apart and replace the
tape.
TIA

Chief McGee wrote:

How many wraps is "properly applied?

I was told three by a gas man. Note that he _only_ uses the heavier
yellow stuff.

Ted

tomcas wrote:

jerry Wass wrote:
p.s.I dunno ANYTHING that will dissolve tetra flouro eththylene.

Hot acids will.

Which hot acids? We used to use some pretty nasty stuff, both hot and
cold, on germanium. All lab ware used was TFE. None dissolved.

Ted

On Mon, 31 May 2004 02:45:22 GMT, (Tom) wrote:

snip
Another problem I recall was in a plant here in Houston years
ago when Teflon tape was used in fittings on a fuel loading hose.
Apparently, the tape was thick enough to act as an insulator
snip

Oddly enough, some years ago I had very good experience with PTFE tape for
that very purpose. We use platinum resistance thermometers to measure seawater
coolant temperatures in power station performance tests. The zinc screw on
connectors on the cables bind to the stainless top of the PRT when splashed
with salt water. I discovered that a turn of PTFE would give enough insulation
and lubrication to make the locking rings easy to remove as opposed to locking
up enough to need to be cut off after a month or two.


Mark Rand
RTFM

Ted Edwards wrote:
tomcas wrote:


jerry Wass wrote:

p.s.I dunno ANYTHING that will dissolve tetra flouro eththylene.



Hot acids will.


Which hot acids? We used to use some pretty nasty stuff, both hot and
cold, on germanium. All lab ware used was TFE. None dissolved.

Ted


Ted
I was wrong. I can't find any reference to hot acid resistance. Sorry,
false alarm.