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Default PTFEed Joints weeping

I don't see how it can work then. You have completely different materials
and no olive, so really you have no chance of it working long term I feel.
I hate plumbing as well, but sometimes needs must as they say, but these
days, I think I'll leave it to the profs as I don't like trying to find my
loft mounted tap with no sight and a loft full of lagging.
Brian

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On Tuesday, 21 February 2017 19:21:39 UTC, Harry Bloomfield wrote:
tabbypurr brought next idea :


3 plumbing joints done with ptfe tape all leak. I mostly don't use ptfe
to
seal joints. 2 of the joints are 15mm compression tee (with one male
end, one
female end) onto an extension piece, the other is extension piece onto
brass
threaded ballcock. 1.5 turns of yellow/gas ptfe tape each, all neatly
in
place. I admit to not being clear how the nut would seal to the tee
it's on.
The one joint done with fibre washer & gloop works fine of course, but
I
don't think that approach can be used with the other joints.


Compression joints should not need anything else to seal them, the
olive is supposed to deform to make the seal between fitting and nut
and the pipe. The pipe end should go well into the fitting, to keep
things aligned.


the joints in question don't have an olive. They're screw threaded
extensions to compression fittings. The tape goes on the screw thread.

And yes, I do use gloop on compressions, old pipe does not seal reliably
without.


NT



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Default PTFEed Joints weeping

On 2/22/2017 5:06 PM, John Rumm wrote:
On 22/02/2017 13:19, DerbyBorn wrote:

That is a mess. Those places where I see PTFE poking out, look to me as
if they were intended to have a fibre washer fitted between flat faces.
You might get PTFE to seal, but only if you can get a regular layer of
PTFE around the threads and of just the right thickness, which is
unlikely - so it will leak.


What I was thinking (Looks like a tap elbow)- I would be inclined to take
the photo to a decent Plumbers Merchant and get the correct fittings for
the job.

Althought PTFE on the tread is not the solution, it should be wound on so
that screwing the fitting will tend to tighten the tape - and not push it
out.


If one were going to try and get a seal on that with PTFE you would need
to be quite careful with the winding of it - basically creating a taper
shape[1] on the thread with the tape, so that the "screw in" resistance
increases sharply as the stub penetrates further into the female thread.

e.g. you start with say 4 or 5 turns toward the tip of the thread and
work up to many more (10 to 20) laid up toward the back of the thread) -
winding the tape on "edgeways" so that it folds up helps build thickness
faster.

Agreed.

Another technique with it is to roll the tape between your fingers to
make "string" and then wind that helically into the threads. You can
also, with care, fabricate a replacement for the fibre washer on a tap
connector by winding several turns of this PTFE "string" on to the step
which should take the washer. Emphatically *not* recommended as a
permanent fix, but in the absence of proper washers I have done it a
couple of times for friends on a Sunday evening, when miles away from my
toolboxes. Most of these include a tobacco tin containing some of these
washers, fuses, fuse wire, and a couple of chocolate blocks. And bits of
red and green/yellow sleeve.
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Default PTFEed Joints weeping

On Wednesday, 22 February 2017 16:59:33 UTC, newshound wrote:
On 2/21/2017 11:27 PM, tabbypurr wrote:
On Tuesday, 21 February 2017 20:35:56 UTC, newshound wrote:
On 2/21/2017 8:15 PM, tabbypurr wrote:
On Tuesday, 21 February 2017 20:05:29 UTC, newshound wrote:
On 2/21/2017 7:56 PM, tabbypurr wrote:
On Tuesday, 21 February 2017 19:32:23 UTC, newshound wrote:
On 2/21/2017 7:03 PM, tabbypurr wrote:

3 plumbing joints done with ptfe tape all leak. I mostly don't use ptfe to seal joints. 2 of the joints are 15mm compression tee (with one male end, one female end) onto an extension piece, the other is extension piece onto brass threaded ballcock. 1.5 turns of yellow/gas ptfe tape each, all neatly in place. I admit to not being clear how the nut would seal to the tee it's on. The one joint done with fibre washer & gloop works fine of course, but I don't think that approach can be used with the other joints.

I'm clearly making a basic mistake here. Did I mention I don't like plumbing?


NT

When you say compression tee, do you mean the pipe has an olive on it?

Like an ordinary compression fitting (that takes pipe with olive) except that one end is reversed, ie male not female. It thus has a nut on that screws onto another fitting. I've added 2 threaded extension pieces, one on each port, to make the combined fitting long enough to reach both pipe and ballcock.

So where is the seal?

I thought the ptfe between the screw threads was going to do it, but clearly not.

Assuming these are parallel threads, you will need
a soft washer on the axial face (unless you fill up the thread clearance
with some sort of fluid sealant)0

yes, hoping I have a suitable washer now.

IIRC fittings to a ballcock are also normally done with an olive.

Neither the current or previous one were/are. The male bit of the compression elbow is screwed onto the ballcock.

OK then you need another soft washer (fibre or rubber) on the axial face.

right

You should not be trying to use PTFE tape to seal any significant water
pressure. But IMHO it is worth using tape on compression fittings *to
reduce the friction*, which means you get more axial pressure for a
given torque. Lots of people tell you that you must not put tape *over*
the olive or the cones but a single turn won't matter.

There are basically three ways to seal with threaded connectors.

One is using tapered threads, these are sealed with fibre, traditionally
hemp but now usually Loctite synthetic thread. A smear of "Boss White"
is also needed.

The second is the washing machine or garden tap connector. You need a
soft washer, either rubber or fibre, trapped in the female (hose)
fitting against the end face of the tap. Tap fittings use a variant of
this, with a thinner fibre washer trapped against the tap by a flange on
the male fitting.

The third is the compression fitting, where you are trapping an olive
between cones on the male and female parts. This relies on squeezing the
olive tightly enough on the pipe so that fluid cannot flow between the
olive and the pipe (sometimes a problem with chromed pipes).

There are liquid sealants which can be applied to threaded joints, I
usually think they are a bit of a "bodge" but sometimes you are
constrained by, for example, a damaged cone on a fixed part, or a scored
pipe. I always carry some in my plumbing toolbox.

I'll see if I can get washers in there, but from a quick look I doubt I can. In which case I could use some sort of fairly quick setting stuff, but that still won't seal the nut to the male end of the compression fitting.

elbow is like this:
https://www.raygrahams.com/images/th...052314_700.jpg

That needs a tapered male thread although you might get away with a washer

I'm more than puzzled by the idea of using a tapered thread with it

Tapered threads are sized so that they become completely tight before
the male thread has bottomed in the female component. On its own, a
tapered thread can't normally make a gas-tight seal, but the leakage
path will be small, so it can be sealed by something like boss white. A
down-side of tapered joints is that you don't have much control of the
orientation of the parts at the point where they become tight. However
by having something like hemp threads wrapped around the male threads,
you can influence the point at which it becomes tight, and hence control
the angular orientation. Tapered threads are not so commonly used in
copper systems, but they were the standard system in "old" iron pipe,
e.g. in "gravity" hot water systems, and are sometimes used for
hand-rails and guard rails. It's a bit of an art building a complicated
"3D" system in iron.


extensions look like this but without the nut on:
https://www.raygrahams.com/images/th...038720_188.jpg

I would expect there to be an olive between the nut and the fitting

which nut and which fitting? I can't imagine how one would get an olive between the extension piece and the elbow.

This picture shows two components. A sort of sleeve with a female thread
at one end, and a male thread on the other.


that's what the extension pieces are

There is a nut on the male
thread. I would expect there to be an olive "inside" the nut. This would
let you seal a piece of copper pipe to the right hand end of the
fitting, by tightening the nut (with the olive in place).


But that lot doesn't come into it. No nut, no olive, no pipe.


NT

The bottom line is, this explains why you are getting leaks with PTFE
tape only.

You either need a rubber or fibre washer to give an axial seal, or taper
threads with sealant, or perhaps some sort of bodge with a setting sealant.

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Default PTFEed Joints weeping

Anyone using PTFE tape on car wheel nuts?


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Default PTFEed Joints weeping

On 22/02/2017 19:01, newshound wrote:
On 2/22/2017 5:06 PM, John Rumm wrote:
On 22/02/2017 13:19, DerbyBorn wrote:

That is a mess. Those places where I see PTFE poking out, look to me as
if they were intended to have a fibre washer fitted between flat faces.
You might get PTFE to seal, but only if you can get a regular layer of
PTFE around the threads and of just the right thickness, which is
unlikely - so it will leak.


What I was thinking (Looks like a tap elbow)- I would be inclined to
take
the photo to a decent Plumbers Merchant and get the correct fittings for
the job.

Althought PTFE on the tread is not the solution, it should be wound
on so
that screwing the fitting will tend to tighten the tape - and not
push it
out.


If one were going to try and get a seal on that with PTFE you would need
to be quite careful with the winding of it - basically creating a taper
shape[1] on the thread with the tape, so that the "screw in" resistance
increases sharply as the stub penetrates further into the female thread.

e.g. you start with say 4 or 5 turns toward the tip of the thread and
work up to many more (10 to 20) laid up toward the back of the thread) -
winding the tape on "edgeways" so that it folds up helps build thickness
faster.

Agreed.

Another technique with it is to roll the tape between your fingers to
make "string" and then wind that helically into the threads. You can
also, with care, fabricate a replacement for the fibre washer on a tap
connector by winding several turns of this PTFE "string" on to the step
which should take the washer. Emphatically *not* recommended as a
permanent fix, but in the absence of proper washers I have done it a
couple of times for friends on a Sunday evening, when miles away from my
toolboxes. Most of these include a tobacco tin containing some of these
washers, fuses, fuse wire, and a couple of chocolate blocks. And bits of
red and green/yellow sleeve.


Yup, I found that I can quite reliably get a seal on parallel male and
female threads using the tape trick. Last time was when I wanted to test
the soundness of the rads after multiple mods and changes. I needed to
bodge a way of connecting my pressure gauge to a rad top connection. The
gauge made a good seal on to the end of a service valve with its
internal washer, then all I needed to do was get a service valve to seal
on the top boss of the rad (having removed the bleed valve). Application
of PTFE as previously described worked nicely. I was then able to
pressurise the system, and leave it for 48 hours to check that there was
no drop off in pressure.


--
Cheers,

John.

/================================================== ===============\
| Internode Ltd - http://www.internode.co.uk |
|-----------------------------------------------------------------|
| John Rumm - john(at)internode(dot)co(dot)uk |
\================================================= ================/
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Default PTFEed Joints weeping

On 22/02/2017 19:30, wrote:
On Wednesday, 22 February 2017 16:59:33 UTC, newshound wrote:
On 2/21/2017 11:27 PM, tabbypurr wrote:
On Tuesday, 21 February 2017 20:35:56 UTC, newshound wrote:
On 2/21/2017 8:15 PM, tabbypurr wrote:
On Tuesday, 21 February 2017 20:05:29 UTC, newshound wrote:
On 2/21/2017 7:56 PM, tabbypurr wrote:
On Tuesday, 21 February 2017 19:32:23 UTC, newshound wrote:
On 2/21/2017 7:03 PM, tabbypurr wrote:

3 plumbing joints done with ptfe tape all leak. I mostly don't use ptfe to seal joints. 2 of the joints are 15mm compression tee (with one male end, one female end) onto an extension piece, the other is extension piece onto brass threaded ballcock. 1.5 turns of yellow/gas ptfe tape each, all neatly in place. I admit to not being clear how the nut would seal to the tee it's on. The one joint done with fibre washer & gloop works fine of course, but I don't think that approach can be used with the other joints.

I'm clearly making a basic mistake here. Did I mention I don't like plumbing?


NT

When you say compression tee, do you mean the pipe has an olive on it?

Like an ordinary compression fitting (that takes pipe with olive) except that one end is reversed, ie male not female. It thus has a nut on that screws onto another fitting. I've added 2 threaded extension pieces, one on each port, to make the combined fitting long enough to reach both pipe and ballcock.

So where is the seal?

I thought the ptfe between the screw threads was going to do it, but clearly not.

Assuming these are parallel threads, you will need
a soft washer on the axial face (unless you fill up the thread clearance
with some sort of fluid sealant)0

yes, hoping I have a suitable washer now.

IIRC fittings to a ballcock are also normally done with an olive.

Neither the current or previous one were/are. The male bit of the compression elbow is screwed onto the ballcock.

OK then you need another soft washer (fibre or rubber) on the axial face.

right

You should not be trying to use PTFE tape to seal any significant water
pressure. But IMHO it is worth using tape on compression fittings *to
reduce the friction*, which means you get more axial pressure for a
given torque. Lots of people tell you that you must not put tape *over*
the olive or the cones but a single turn won't matter.

There are basically three ways to seal with threaded connectors.

One is using tapered threads, these are sealed with fibre, traditionally
hemp but now usually Loctite synthetic thread. A smear of "Boss White"
is also needed.

The second is the washing machine or garden tap connector. You need a
soft washer, either rubber or fibre, trapped in the female (hose)
fitting against the end face of the tap. Tap fittings use a variant of
this, with a thinner fibre washer trapped against the tap by a flange on
the male fitting.

The third is the compression fitting, where you are trapping an olive
between cones on the male and female parts. This relies on squeezing the
olive tightly enough on the pipe so that fluid cannot flow between the
olive and the pipe (sometimes a problem with chromed pipes).

There are liquid sealants which can be applied to threaded joints, I
usually think they are a bit of a "bodge" but sometimes you are
constrained by, for example, a damaged cone on a fixed part, or a scored
pipe. I always carry some in my plumbing toolbox.

I'll see if I can get washers in there, but from a quick look I doubt I can. In which case I could use some sort of fairly quick setting stuff, but that still won't seal the nut to the male end of the compression fitting.

elbow is like this:
https://www.raygrahams.com/images/th...052314_700.jpg

That needs a tapered male thread although you might get away with a washer

I'm more than puzzled by the idea of using a tapered thread with it

Tapered threads are sized so that they become completely tight before
the male thread has bottomed in the female component. On its own, a
tapered thread can't normally make a gas-tight seal, but the leakage
path will be small, so it can be sealed by something like boss white. A
down-side of tapered joints is that you don't have much control of the
orientation of the parts at the point where they become tight. However
by having something like hemp threads wrapped around the male threads,
you can influence the point at which it becomes tight, and hence control
the angular orientation. Tapered threads are not so commonly used in
copper systems, but they were the standard system in "old" iron pipe,
e.g. in "gravity" hot water systems, and are sometimes used for
hand-rails and guard rails. It's a bit of an art building a complicated
"3D" system in iron.


extensions look like this but without the nut on:
https://www.raygrahams.com/images/th...038720_188.jpg

I would expect there to be an olive between the nut and the fitting

which nut and which fitting? I can't imagine how one would get an olive between the extension piece and the elbow.

This picture shows two components. A sort of sleeve with a female thread
at one end, and a male thread on the other.

that's what the extension pieces are

There is a nut on the male
thread. I would expect there to be an olive "inside" the nut. This would
let you seal a piece of copper pipe to the right hand end of the
fitting, by tightening the nut (with the olive in place).

But that lot doesn't come into it. No nut, no olive, no pipe.


NT

The bottom line is, this explains why you are getting leaks with PTFE
tape only.

You either need a rubber or fibre washer to give an axial seal, or taper
threads with sealant, or perhaps some sort of bodge with a setting sealant.


Done & leakproof
http://i68.tinypic.com/xc9pjn.jpg


Nice job, that ought to do it ;-)



--
Cheers,

John.

/================================================== ===============\
| Internode Ltd - http://www.internode.co.uk |
|-----------------------------------------------------------------|
| John Rumm - john(at)internode(dot)co(dot)uk |
\================================================= ================/
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Default PTFEed Joints weeping

In article ,
charles wrote:
It probably doesn't help, but I'd have done all of that using end feed
solder fittings. Which if you take care, never leak.


Very difficult to get a good joint on a pipe that still has water
around.


Not difficult to drain those from a tank?


I wouldn't wave a blowlamp near a plastic water tank, either,


You protect it from heat - same as anything else close to where you're
soldering, if needed.

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Dave Plowman London SW
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Default PTFEed Joints weeping

In article 2,
DerbyBorn wrote:
Anyone using PTFE tape on car wheel nuts?


Why would you? A smear of copper grease will stop them seizing.

--
*Parenthetical remarks (however relevant) are (usually) unnecessary *

Dave Plowman London SW
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Default PTFEed Joints weeping

On Tuesday, 21 February 2017 23:29:30 UTC, tabby wrote:

Of all the plumbing spanners my flat stamped one is one of the more useful. It's more than thick enough to get serious torque on the nuts - but it is the thickest stamped one I've ever seen. The slight offset makes it even more getinnable. It's designed for car fans.


Laser brand.


NT


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I find many do, or use as the reason why they are using PTFE tape, often
fully covering the olive as well.


+1.

In my house it has one application - on radiator tails and top bungs.
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On Thursday, 23 February 2017 21:05:14 UTC, DerbyBorn wrote:

I find many do, or use as the reason why they are using PTFE tape, often
fully covering the olive as well.


+1.

In my house it has one application - on radiator tails and top bungs.


Maybe it's time for a wiki page on ptfe.


NT
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In article ,
John Rumm wrote:
I find many do, or use as the reason why they are using PTFE tape,
often fully covering the olive as well.


Covering the olive will alter the sealing properties, and can be used to
fix some categories of leak.


I do use PTFE on the olive after cleaning the pipes thoroughly, and making
sure there are no inline scratches. Examine more carefully than I would
for a solder fitting.

And oddly, never have a compression fitting leak. ;-)

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