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

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.

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

On 2/21/2017 7:03 PM, 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?
IIRC fittings to a ballcock are also normally done with an olive.

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.

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?

Well basic mistake one to my mind is using PTFE tape with compression
joints. PTFE and compression joints don't mix - where did you put the
tape anyway?

--
Chris Green
·

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.

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.

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


NT

On 2/21/2017 7:56 PM, 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? 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




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.


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

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




NT

On 2/21/2017 7:36 PM, Chris Green wrote:
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?

Well basic mistake one to my mind is using PTFE tape with compression
joints. PTFE and compression joints don't mix - where did you put the
tape anyway?

Although this is the conventional wisdom, IMHO it is always worth
putting PTFE tape on the threads because it reduces the friction
coefficient. So you get more axial force for a given torque. It's the
axial force which makes the seal.

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

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.


a puzzled NT

newshound wrote:
On 2/21/2017 7:36 PM, Chris Green wrote:
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?

Well basic mistake one to my mind is using PTFE tape with compression
joints. PTFE and compression joints don't mix - where did you put the
tape anyway?

Although this is the conventional wisdom, IMHO it is always worth
putting PTFE tape on the threads because it reduces the friction
coefficient. So you get more axial force for a given torque. It's the
axial force which makes the seal.

It's the squishing of the olive round the pipe that makes the seal
surely. OK, some PTFE tape on the thread may help by lubricating it
but surely a quick dab of grease or oil would actually work better as
a lubricant.

--
Chris Green
·

On 2/21/2017 8:15 PM, 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. 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).



a puzzled NT

On 21/02/2017 20:08, newshound wrote:
On 2/21/2017 7:36 PM, Chris Green wrote:
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?

Well basic mistake one to my mind is using PTFE tape with compression
joints. PTFE and compression joints don't mix - where did you put the
tape anyway?

Although this is the conventional wisdom, IMHO it is always worth
putting PTFE tape on the threads because it reduces the friction
coefficient. So you get more axial force for a given torque. It's the
axial force which makes the seal.

Wisdom says use a proper lubricant.

Lubricant doesn't creep like PTFE.

PTFE is intended for taper threads.

Whenever I see PTFE tape on a compression fitting you can always tell
it's a rank amateur.

In practice you can supply more than enough force to a compression
fitting to destroy an olive, such there ought not be any need for lubricant.

On 21/02/2017 20:44, Fredxxx wrote:

In practice you can supply more than enough force to a compression
fitting to destroy an olive, such there ought not be any need for
lubricant.

That's not always the case - it really depends on location and how
easily you can get a spanner on it (not to mention the type of
spanner[1]). In some circumstances you can't get adequate torque without
lubrication on the threads, and PTFE does the job without getting grease
all over the place.

[1] 'Orible stamped steel things like this:

http://wiki.diyfaq.org.uk/index.php/...eelSpanner.jpg

will get into all kinds of gaps more manly spanners won't, but they can
be a bugger to get enough torque on the nut - especially on 22mm and
larger fittings.


--
Cheers,

John.

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

On 21/02/2017 19:03, 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.

Personally I would not use gas PTFE in this application - its can be too
thick.

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.

Some photos of the actual fittings you are using might help to get a
clearer understanding.

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

Generally if its got an olive, and the pipe is clean - then it will
normally seal fine without additional stuff. If you are trying to get a
seal on a threaded connector. Then you need either a washer or O ring
that can seal against the flat on the surface of the fitting (e.g. like
on a tap connector), or you need a tapered male fitting + sealing
"stuff" to go into it. (ideally tapered fittings should be used in pairs
i.e. taper male into taper female - however in reality a taper male will
normally seal into a parallel female with lots of PTFE (as commonly done
on rad tails))


--
Cheers,

John.

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

On 21/02/2017 20:15, wrote:

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.

That sounds like you have a male - female nipple.
They aren't extension pieces for extending a compression joint.
They have tapered threads and the compression fitting will have parallel
threads.

You need a short bit of pipe and some proper compression or solder
fittings, or do it the easy way and use pushfit.

On Tuesday, 21 February 2017 19:03:50 UTC, tabby 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

Here's the steward of the bar in question
http://i66.tinypic.com/xoprer.jpg


NT

On Tuesday, 21 February 2017 20:33:07 UTC, Chris Green wrote:
newshound wrote:
On 2/21/2017 7:36 PM, Chris Green wrote:
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?

Well basic mistake one to my mind is using PTFE tape with compression
joints. PTFE and compression joints don't mix - where did you put the
tape anyway?

Although this is the conventional wisdom, IMHO it is always worth
putting PTFE tape on the threads because it reduces the friction
coefficient. So you get more axial force for a given torque. It's the
axial force which makes the seal.

It's the squishing of the olive round the pipe that makes the seal
surely. OK, some PTFE tape on the thread may help by lubricating it
but surely a quick dab of grease or oil would actually work better as
a lubricant.

The problem joints don't involve a pipe or olive. They're where 2 parts are screwed together.


NT

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

On Tuesday, 21 February 2017 21:10:30 UTC, John Rumm wrote:
On 21/02/2017 20:44, Fredxxx wrote:

In practice you can supply more than enough force to a compression
fitting to destroy an olive, such there ought not be any need for
lubricant.

That's not always the case - it really depends on location and how
easily you can get a spanner on it (not to mention the type of
spanner[1]). In some circumstances you can't get adequate torque without
lubrication on the threads, and PTFE does the job without getting grease
all over the place.

[1] 'Orible stamped steel things like this:

http://wiki.diyfaq.org.uk/index.php/...eelSpanner.jpg

will get into all kinds of gaps more manly spanners won't, but they can
be a bugger to get enough torque on the nut - especially on 22mm and
larger fittings.

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.


NT

On Tuesday, 21 February 2017 22:56:53 UTC, dennis@home wrote:
On 21/02/2017 20:15, tabbypurr wrote:

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.

That sounds like you have a male - female nipple.

ok doc.

They aren't extension pieces for extending a compression joint.
They have tapered threads and the compression fitting will have parallel
threads.

You need a short bit of pipe and some proper compression or solder
fittings, or do it the easy way and use pushfit.

Not enough room - I could redo the whole area using new fittings, and might have to. Maybe I could attach the 'extensions' whatever they may be with epoxy.


NT

Chris Green wrote in :

newshound wrote:
On 2/21/2017 7:36 PM, Chris Green wrote:
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?

Well basic mistake one to my mind is using PTFE tape with
compression joints. PTFE and compression joints don't mix - where
did you put the tape anyway?

Although this is the conventional wisdom, IMHO it is always worth
putting PTFE tape on the threads because it reduces the friction
coefficient. So you get more axial force for a given torque. It's the
axial force which makes the seal.

It's the squishing of the olive round the pipe that makes the seal
surely. OK, some PTFE tape on the thread may help by lubricating it
but surely a quick dab of grease or oil would actually work better as
a lubricant.


+1

wrote in news:1a3a4d7f-1f3f-4e6f-b69c-
:

http://i66.tinypic.com/xoprer.jpg

Is this a wind up?

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

+1

On Tuesday, 21 February 2017 23:57:05 UTC, DerbyBorn wrote:
tabbypurr wrote in news:1a3a4d7f-1f3f-4e6f-b69c-
:

http://i66.tinypic.com/xoprer.jpg

Is this a wind up?

why?


NT

On 21/02/2017 23:23, wrote:
On Tuesday, 21 February 2017 19:03:50 UTC, tabby 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

Here's the steward of the bar in question
http://i66.tinypic.com/xoprer.jpg

Not sure you want to start from there! ;-)

It looks like you have a parallel thread BSP female on a male parallel
thread BSP coming out of the tank. That's never going to seal without
serious bodgery. The same propably goes for the other two fittings as
well alas.

You want a straight tap connector to 15mm compression fitting on the
tank, and two bits of copper pipe and an elbow soldered onto the stub of
pipe coming out of that Yorkshire fitting to join to it.



--
Cheers,

John.

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

On Wednesday, 22 February 2017 01:19:37 UTC, John Rumm wrote:
On 21/02/2017 23:23, tabbypurr wrote:
On Tuesday, 21 February 2017 19:03:50 UTC, tabby 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

Here's the steward of the bar in question
http://i66.tinypic.com/xoprer.jpg

Not sure you want to start from there! ;-)

It looks like you have a parallel thread BSP female on a male parallel
thread BSP coming out of the tank. That's never going to seal without
serious bodgery. The same propably goes for the other two fittings as
well alas.

I realise that now. I have a tube of serious bodgery somewhere. I don't know how the previous elbow fitting sealed, it was connected the same way, but I couldn't get it to reseal on the new ballcock.

You want a straight tap connector to 15mm compression fitting on the
tank, and two bits of copper pipe and an elbow soldered onto the stub of
pipe coming out of that Yorkshire fitting to join to it.

Too much flammable stuff in close proximity to solder in situ. If I use a straight compression to connect to a soldered elbow it'll be too long, and the hand bent pipe only barely manages to be straight enough to fit what's there now. I guess I'll need to cut the whole area out & start afresh. Fun. Maybe I should try that tube of bodgery first.


NT

On 22/02/17 02:04, wrote:

Too much flammable stuff in close proximity to solder in situ.

Not sure that's true. those soldering mats are very good and a squeegee
spray full of water is a handy local extinguisher BUT if you remove
everything in the picture you have at one end what looks like a washered
joint, and at the other what could be a bog standard olived compression,
and the ability to create right angle pipework in between remotely soldered.


If I use a straight compression to connect to a soldered elbow it'll
be too long, and the hand bent pipe only barely manages to be
straight enough to fit what's there now. I guess I'll need to cut the
whole area out & start afresh. Fun. Maybe I should try that tube of
bodgery first.


NT



--
"The great thing about Glasgow is that if there's a nuclear attack it'll
look exactly the same afterwards."

Billy Connolly

wrote in news:c5ec582a-ff23-49d0-bdde-feffaf309aa0
@googlegroups.com:

On Tuesday, 21 February 2017 23:57:05 UTC, DerbyBorn wrote:
tabbypurr wrote in news:1a3a4d7f-1f3f-4e6f-b69c-
:

http://i66.tinypic.com/xoprer.jpg

Is this a wind up?

why?


NT

It is the sort of fitting that needs washers.

On 22/02/2017 02:04, wrote:
On Wednesday, 22 February 2017 01:19:37 UTC, John Rumm wrote:
On 21/02/2017 23:23, tabbypurr wrote:
On Tuesday, 21 February 2017 19:03:50 UTC, tabby 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

Here's the steward of the bar in question
http://i66.tinypic.com/xoprer.jpg

Too much flammable stuff in close proximity to solder in situ. If I
use a straight compression to connect to a soldered elbow it'll be
too long, and the hand bent pipe only barely manages to be straight
enough to fit what's there now. I guess I'll need to cut the whole
area out & start afresh. Fun. Maybe I should try that tube of bodgery
first.

Alternative, straight compression on the vertical pipe to connect to a
12" section of plastic pipe. Right angled tap connector on the other end
of the plastic pipe. The plastic can then drop down, gently bend into
180deg U shape, and allow the end to come back up to the ballcock with
the RA tap connector ready to screw on. That way you don't need to be
constrained by the layout of the start and end points or need to solder
in situ.


--
Cheers,

John.

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

laid this down on his screen :
Here's the steward of the bar in question
http://i66.tinypic.com/xoprer.jpg

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.

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.

On Tuesday, February 21, 2017 at 7:48:05 PM UTC, Chris Green wrote:

Well basic mistake one to my mind is using PTFE tape with compression
joints. PTFE and compression joints don't mix -

The apprentice uses it without thinking.
The journeyman avoids it without thinking.
The master uses it thoughtfully.


I've never had a problem with it.

wrote in news:6e07a80c-d49f-477e-ba82-
:

On Tuesday, February 21, 2017 at 7:48:05 PM UTC, Chris Green wrote:

Well basic mistake one to my mind is using PTFE tape with compression
joints. PTFE and compression joints don't mix -

The apprentice uses it without thinking.
The journeyman avoids it without thinking.
The master uses it thoughtfully.


I've never had a problem with it.




It is slapping it onto the treads thinking it will improve the seal that is
so wrong. The thread is a clamping mechanism. The olive and cones do the
sealing. If these are clean then nothing else is needed. (Stand back for
the lubrication comments) Oil could be a good lube, but too often people
overtighten from the outset. Mauling a joint!

On 22/02/2017 16:05, DerbyBorn wrote:
wrote in news:6e07a80c-d49f-477e-ba82-
:

On Tuesday, February 21, 2017 at 7:48:05 PM UTC, Chris Green wrote:

Well basic mistake one to my mind is using PTFE tape with compression
joints. PTFE and compression joints don't mix -

The apprentice uses it without thinking.
The journeyman avoids it without thinking.
The master uses it thoughtfully.


I've never had a problem with it.




It is slapping it onto the treads thinking it will improve the seal that is
so wrong.

Is anyone suggesting that?

The thread is a clamping mechanism. The olive and cones do the
sealing. If these are clean then nothing else is needed.

If... alas not something that can always be relied upon in real life. It
only takes a deep scratch on a pipe that can't be cut back further, and
can't be soldered, or a fitting that must be re-used etc.

Of the many hundreds of compression joints I have made, I have only had
to resort to extra steps to get them to seal a handful of times (in fact
only two or three that come to mind). Can't see the point in rejecting a
solution that works where there is no easy alternative.

(Stand back for
the lubrication comments) Oil could be a good lube,

It could, but given that most plumbing kits will include PTFE, and it
*is* supremely slippery while also being non messy, there is no harm in
using it when necessary IMO.

(or even when not, if you don't enjoy metal to metal squawking - PTFE
also makes compression joists very quiet to tighten)

but too often people
overtighten from the outset. Mauling a joint!

Its actually harder than many imagine - they will usually take fairly
serious over tightening before they actually fail unless you distort the
nuts.

You are more likely to have a problem with poorly fitting spanners, than
too much torque alone.



--
Cheers,

John.

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

On 2/21/2017 11:27 PM, 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.

On 2/21/2017 8:29 PM, Chris Green wrote:
newshound wrote:
On 2/21/2017 7:36 PM, Chris Green wrote:
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?

Well basic mistake one to my mind is using PTFE tape with compression
joints. PTFE and compression joints don't mix - where did you put the
tape anyway?

Although this is the conventional wisdom, IMHO it is always worth
putting PTFE tape on the threads because it reduces the friction
coefficient. So you get more axial force for a given torque. It's the
axial force which makes the seal.

It's the squishing of the olive round the pipe that makes the seal
surely. OK, some PTFE tape on the thread may help by lubricating it
but surely a quick dab of grease or oil would actually work better as
a lubricant.

No, you will get lower friction with PTFE.

I still maintain it is the axial force which is important, although it
is true this is converted to a radial force by the contact between the
cone and the olive. Actually this is an argument for having PTFE tape
between the olive and the cone.

In article ,
wrote:
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.

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.

--
*How many roads must a man travel down before he admits he is lost? *

Dave Plowman London SW
To e-mail, change noise into sound.

On 2/21/2017 8:44 PM, Fredxxx wrote:
On 21/02/2017 20:08, newshound wrote:


Whenever I see PTFE tape on a compression fitting you can always tell
it's a rank amateur.

Or possibly someone who was publishing tribology research in the 1970's
and 80's.

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.

--
Cheers,

John.

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

In article ,
Dave Plowman (News) wrote:
In article ,
wrote:
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.

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

--
from KT24 in Surrey, England