A clerk at my local Ace Hardware told me to use Teflon tape on the
pipe threads but not the compression fittings. I'm trying to stop a
very slow seepage from the couplings and flex hose surrounding a
quarter turn shut off valve serving the cold water faucet to a
bathroom sink.

Is this advice correct?

GROVER wrote:
A clerk at my local Ace Hardware told me to use Teflon tape on the
pipe threads but not the compression fittings. I'm trying to stop a
very slow seepage from the couplings and flex hose surrounding a
quarter turn shut off valve serving the cold water faucet to a
bathroom sink.

Is this advice correct?

Sometimes a little teflon paste in and around the compression sleeve will
help keep it sealed up.

Jon

"GROVER" wrote in message
...
A clerk at my local Ace Hardware told me to use Teflon tape on the
pipe threads but not the compression fittings. I'm trying to stop a
very slow seepage from the couplings and flex hose surrounding a
quarter turn shut off valve serving the cold water faucet to a
bathroom sink.

Is this advice correct?

I just changed a quarter turn valve behind toilet. Did not replace
compression fitting on copper pipe as I would need to remove toilet to cut
the old one off. I used teflon paste made for gas line work, it is thicker.
No leaks. WW

GROVER wrote in :

A clerk at my local Ace Hardware told me to use Teflon tape on the
pipe threads but not the compression fittings. I'm trying to stop a
very slow seepage from the couplings and flex hose surrounding a
quarter turn shut off valve serving the cold water faucet to a
bathroom sink.

Is this advice correct?

Depends on how that flex hose is coming into the fitting. Ideally you
want the hose fitting coming into the connection fairly straight so it's
not pulling off to the side. This makes a good all around seal.
Sometimes the available lengths of flex hose are just not good.

(assume you mean these flex hoses?)
http://www.direcsupply.com/products/...200250%20d.jpg

In that case you get a extra long one and loop it.
Sorry, can't find a pic of this offhand.

GROVER wrote:
A clerk at my local Ace Hardware told me to use Teflon tape on the
pipe threads but not the compression fittings. I'm trying to stop a
very slow seepage from the couplings and flex hose surrounding a
quarter turn shut off valve serving the cold water faucet to a
bathroom sink.

Is this advice correct?

It is correct advice. Either tighten it or replace it and don't over
tighten. Teflon tape will do nothing on this, the threads do not hold
water, the compression ring does.


--
LSMFT

Those who would give up Essential Liberty
to purchase a little Temporary Safety,
deserve neither Liberty nor Safety.

On Mon, 31 Jan 2011 08:50:02 -0800 (PST), GROVER
wrote:

A clerk at my local Ace Hardware told me to use Teflon tape on the
pipe threads but not the compression fittings. I'm trying to stop a
very slow seepage from the couplings and flex hose surrounding a
quarter turn shut off valve serving the cold water faucet to a
bathroom sink.

Is this advice correct?
Yes it is.

On Jan 31, 11:50*am, GROVER wrote:
A clerk *at my local Ace Hardware told me to use Teflon tape on the
pipe threads but not the compression fittings. *I'm trying to stop a
very slow seepage from the couplings and flex hose surrounding a
quarter turn shut off valve serving the cold water faucet to a
bathroom sink.

*Is this advice correct?

Yes it is. You probably need to replace the brass compression ring.
If you do no thave some extra length in the line it is on you will
need to replace that piece as well. Compression fittings can be
reassembled but not infinitely.

On 01/31/2011 10:50 AM, GROVER wrote:
A clerk at my local Ace Hardware told me to use Teflon tape on the
pipe threads but not the compression fittings. I'm trying to stop a
very slow seepage from the couplings and flex hose surrounding a
quarter turn shut off valve serving the cold water faucet to a
bathroom sink.

Is this advice correct?


Yes.

See the Wikipedia article on compression fittings to understand how they
work. Most important thing with those is to be clean and gentle with them.

Pipe threads are tapered according to the National Pipe Thread (NPT)
standard. See also the Wikipedia article about that. You need teflon
tape or a goopy sealant and a small pipe wrench to stop the leak there.

GROVER wrote:
A clerk at my local Ace Hardware told me to use Teflon tape on the
pipe threads but not the compression fittings. I'm trying to stop a
very slow seepage from the couplings and flex hose surrounding a
quarter turn shut off valve serving the cold water faucet to a
bathroom sink.

Is this advice correct?

The purpose of Teflon tape is to lubricate the threads so the fittings go
together more easily. Teflon tape is not designed to be a sealant, even
though it may act minimally in this capacity.

LSMFT wrote:
GROVER wrote:

A clerk at my local Ace Hardware told me to use Teflon tape on the
pipe threads but not the compression fittings. I'm trying to stop a
very slow seepage from the couplings and flex hose surrounding a
quarter turn shut off valve serving the cold water faucet to a
bathroom sink.

Is this advice correct?


It is correct advice. Either tighten it or replace it and don't over
tighten. Teflon tape will do nothing on this, the threads do not hold
water, the compression ring does.


My own experience begs me to differ with you on that point.

While it may not be kosher, I've stopped slow leaks on compression
fittings by trimming a few inches of teflon tape down to about 3/16"
width and wrapping that narrow strip around the stub end of the tubing
adjacent to the compression ring. When reassembled the teflon tape gets
squeezed into the space between the valve outlet, the stub end of the
tubing and the compression ring, sealing whatever path was leaking just
fine.

YMMV, but it's worked for me at least three times already.

Jeff

--
Jeffry Wisnia
(W1BSV + Brass Rat '57 EE)
The speed of light is 1.8*10e12 furlongs per fortnight.

We need to know if teflon tape is a lubricant, or water
displacer. And if it's got any relation to Nazis.

--
Christopher A. Young
Learn more about Jesus
www.lds.org
..


"GROVER" wrote in message
...
A clerk at my local Ace Hardware told me to use Teflon tape
on the
pipe threads but not the compression fittings. I'm trying
to stop a
very slow seepage from the couplings and flex hose
surrounding a
quarter turn shut off valve serving the cold water faucet to
a
bathroom sink.

Is this advice correct?

On Mon, 31 Jan 2011 16:32:35 -0600, "HeyBub"
wrote:

GROVER wrote:
A clerk at my local Ace Hardware told me to use Teflon tape on the
pipe threads but not the compression fittings. I'm trying to stop a
very slow seepage from the couplings and flex hose surrounding a
quarter turn shut off valve serving the cold water faucet to a
bathroom sink.

Is this advice correct?

The purpose of Teflon tape is to lubricate the threads so the fittings go
together more easily. Teflon tape is not designed to be a sealant, even
though it may act minimally in this capacity.

Actually teflon tape does both. Before teflon tape a waxed linen
thread was often used to accomplish the same thing. Wax alone would
not do the job and it is an excellent lubricant - and plain linen
thread would just shred, doing no good at all.

wrote:
On Mon, 31 Jan 2011 16:32:35 -0600, "HeyBub"
wrote:

GROVER wrote:
A clerk at my local Ace Hardware told me to use Teflon tape on the
pipe threads but not the compression fittings. I'm trying to stop a
very slow seepage from the couplings and flex hose surrounding a
quarter turn shut off valve serving the cold water faucet to a
bathroom sink.

Is this advice correct?

The purpose of Teflon tape is to lubricate the threads so the
fittings go together more easily. Teflon tape is not designed to be
a sealant, even though it may act minimally in this capacity.

Actually teflon tape does both. Before teflon tape a waxed linen
thread was often used to accomplish the same thing. Wax alone would
not do the job and it is an excellent lubricant - and plain linen
thread would just shred, doing no good at all.

Sort of. Teflon tape is indicated for tapered threads where its lubrication
properties help to tighten the contact, thereby deforming the threads to
create the seal.

Parallel threads do not deform and no amount of tightening will cause them
to seal. To seal a parallel thread, you need some additional form of
sealant: a gasket, deforming ring, sealant, etc. Teflon tape does no good at
all on parallel threads. Nada.

Even where indicated, tape can be a hazard. Over-use can prevent the threads
from deforming, minimizing the seal leading to leaks, and bits of tape
hanging in the passageway can break off and compromise downstream valves or
orfices.

On Mon, 31 Jan 2011 20:47:43 -0500, wrote:

On Mon, 31 Jan 2011 16:32:35 -0600, "HeyBub"
wrote:

GROVER wrote:
A clerk at my local Ace Hardware told me to use Teflon tape on the
pipe threads but not the compression fittings. I'm trying to stop a
very slow seepage from the couplings and flex hose surrounding a
quarter turn shut off valve serving the cold water faucet to a
bathroom sink.

Is this advice correct?

The purpose of Teflon tape is to lubricate the threads so the fittings go
together more easily. Teflon tape is not designed to be a sealant, even
though it may act minimally in this capacity.

Actually teflon tape does both. Before teflon tape a waxed linen
thread was often used to accomplish the same thing. Wax alone would
not do the job and it is an excellent lubricant - and plain linen
thread would just shred, doing no good at all.

Never heard of the waxed linen thread, but I used pipe dope long
before Teflon came around.
Think it was a combination of linseed oil and red lead, but I read
that somewhere and won't stand by it.
Besides, it was always a white or off white color.
The old pipe dope always hardened too.
Any old pipe I ever took apart had rock hard dope.
Didn't cause adhesion, just more force to break the bond.
Looks like there's no museum of pipe dope where you can get the facts.
I did run across a quote of ANSI/NSF 61 standards that says white
Teflon tape is only good to 3/8".
I've been using whatever cheap Teflon tape I have around on up to
3/4" and might have used that on a much bigger header I reworked
when I put a new boiler in at my ma's house.
But I may have used a TFE paste on that.

--Vic

On Jan 31, 2:57*pm, jeff_wisnia
wrote:
LSMFT wrote:
GROVER wrote:

A clerk *at my local Ace Hardware told me to use Teflon tape on the
pipe threads but not the compression fittings. *I'm trying to stop a
very slow seepage from the couplings and flex hose surrounding a
quarter turn shut off valve serving the cold water faucet to a
bathroom sink.

* Is this advice correct?

It is correct advice. Either tighten it or replace it and don't over
tighten. Teflon tape will do nothing on this, the threads do not hold
water, the compression ring does.

My own experience begs me to differ with you on that point.

While it may not be kosher, I've stopped slow leaks on compression
fittings by trimming a few inches of teflon tape down to about 3/16"
width and wrapping that narrow strip around the stub end of the tubing
adjacent to the compression ring. When reassembled the teflon tape gets
squeezed into the space between the valve outlet, the stub end of the
tubing and the compression ring, sealing whatever path was leaking just
fine.

YMMV, but it's worked for me at least three times already.

Jeff

--
Jeffry Wisnia
(W1BSV + Brass Rat '57 EE)
The speed of light is 1.8*10e12 furlongs per fortnight.

I've got to agree with Jeff.

Yes, compression fitting have straight threads and a compression
sleeve to do the sealing
BUT telfon tape or teflon dope can be used on stubborn fittings that
refuse to seal.

I used to to be a purist and replace fittings that wouldn't seat
properly & seal.
I took the tip from a master plumber who I saw using teflon dope on
compression fitted angle stops.

I asked him.....
"Hey Robert, what's up with the telfon dope on the compression
fittings?
They're supposed to be metal to metal contact....no dope required."

To which he replied....
"Yeah, I know but it seems like my crew and I used to invariably get
one to two 'leakers' out of a houseful of compression fitted angle
stops. Often requiring the valve to be replaced or worse...... a call
back the day. Since I've switched to teflon dope; leakers, no call
backs."

His experience was hard to argue with. He & his crews probably do
more angle stops in a couple months than I have in my entire life. I
switched to doping compression fittings. Goes against my engineer's
sensibilities but it works.

The dope or tape doesn't seal the straight threads but serves to help
the compression sleeve & seat to seal. Maybe modern compression seats
& sleeves aren't as well made as years ago and they have
imperfections / deformities that need the dope?


Now to address the dope or tape question.

"it's a lubricant", "no, it's sealant".......... "no, it's both".

They are sealants that provide come lubrication BUT their main purpose
is "sealant", here's why.........

Standard tapered pipe threads (NPT) will NOT seal without a sealant.
Yes, they get torqued together BUT no matter how well lubricated or
how much they're tightened, they will NOT completely seal.

BTDT....... YEARS ago I did the experiment of trying to get NPT pipe
threads to seal with lube alone; they can't, they won't. The
internal threads & external thread have a bit of clearance so even
when they are "tight" there is an volume beyond the tip of the
external thread, ending in the valley of the internal thread.

This "gap" between the tips & the valleys is where the pipe dope needs
to be, to seal the NPT threads.
Without tape or dope, you'll always get a bit of leakage; back
through that spiral path.

The good new is, a lot of domestic water carries minerals that will do
the job of pipe dope..... eventually.

In fact, check out the MSDS for Loctite HVAC Blue
http://www.deltaindustrial.com/MSDS/...ntCompound.pdf

The non-volatile part is calcium carbonate....... HVAC Blue is user
applied "hard water deposits"

Now for those who really want to "geek out".... there are "dry seal"
pipe threads (NPTF) but if anyone ever suggests that you use them, I
recommend asking them to "show me how".

I've used them, YEARS ago and can attest, they are nasty & a real
PITA. Do whatever you can do to avoid them. The are close tolerance
and meant to create a true interference fit. The whole point is "seal
without sealant". Made for military or applications where sealants
(dope or tape) are a no-no.
Bad enough in plated steel, in stainless they are a nightmare.

cheers
Bob

"GROVER" wrote in message
A clerk at my local Ace Hardware told me to use Teflon tape on the
pipe threads but not the compression fittings. I'm trying to stop a
very slow seepage from the couplings and flex hose surrounding a
quarter turn shut off valve serving the cold water faucet to a
bathroom sink.

Is this advice correct?

How cold is the water in that pipe? Perhaps it is not a leak, rather
condensation? (like on the outside of a glass of ice water...)

Matt wrote in
:

On 01/31/2011 10:50 AM, GROVER wrote:
A clerk at my local Ace Hardware told me to use Teflon tape on the
pipe threads but not the compression fittings. I'm trying to stop a
very slow seepage from the couplings and flex hose surrounding a
quarter turn shut off valve serving the cold water faucet to a
bathroom sink.

Is this advice correct?


Yes.

See the Wikipedia article on compression fittings to understand how
they work. Most important thing with those is to be clean and gentle
with them.

Pipe threads are tapered according to the National Pipe Thread (NPT)
standard. See also the Wikipedia article about that. You need teflon
tape or a goopy sealant and a small pipe wrench to stop the leak
there.

http://en.wikipedia.org/wiki/Compression_fittings

Good article. Didn't know this part. Never looked that closely.

"To work properly, the ferrule must be oriented correctly; typically the
ferrule is fitted such that the longest sloping face of the ferrule faces
away from the nut."

On 1/31/2011 5:57 PM, jeff_wisnia wrote:
LSMFT wrote:
GROVER wrote:

A clerk at my local Ace Hardware told me to use Teflon tape on the
pipe threads but not the compression fittings. I'm trying to stop a
very slow seepage from the couplings and flex hose surrounding a
quarter turn shut off valve serving the cold water faucet to a
bathroom sink.

Is this advice correct?


It is correct advice. Either tighten it or replace it and don't over
tighten. Teflon tape will do nothing on this, the threads do not hold
water, the compression ring does.


My own experience begs me to differ with you on that point.

While it may not be kosher, I've stopped slow leaks on compression
fittings by trimming a few inches of teflon tape down to about 3/16"
width and wrapping that narrow strip around the stub end of the tubing
adjacent to the compression ring. When reassembled the teflon tape gets
squeezed into the space between the valve outlet, the stub end of the
tubing and the compression ring, sealing whatever path was leaking just
fine.

YMMV, but it's worked for me at least three times already.

Jeff

Works for me also, tape or pipe dope.