When tightening compression joints it always seems a bit kind-of hit
and miss and they seem to need to be VERY tight to not leak - so tight
I worry about damaging the joint or pipe.

I normally put grease on the threads which makes them easier to
tighten but of course doesn't reduce the pressure on the parts..

After fitting a radiator the screw cap had started to crack after it
was leaking a tiny bit and I tightened it some more. So I'm wondering
if I'm doing something wrong, perhaps the pipe should be pulled out a
little bit from the joint before tightening? or anything else?

Also are the silver joints stronger than gold ones?

405 TD Estate wrote:
When tightening compression joints it always seems a bit kind-of hit
and miss and they seem to need to be VERY tight to not leak - so tight
I worry about damaging the joint or pipe.

I normally put grease on the threads which makes them easier to
tighten but of course doesn't reduce the pressure on the parts..

After fitting a radiator the screw cap had started to crack after it
was leaking a tiny bit and I tightened it some more. So I'm wondering
if I'm doing something wrong, perhaps the pipe should be pulled out a
little bit from the joint before tightening? or anything else?

Also are the silver joints stronger than gold ones?

In my limited experience compression joints leak if

a) the pipe isn't 100% aligned with the fitting, i.e. approaching at a
slight angle.
b) the pipe isn't fully pushed into the fitting. Sometimes difficult to
keep it pushed in when both hands are holding spanners.
c) the cut isn't made with a proper pipe cutter

stuart noble wrote:
405 TD Estate wrote:
When tightening compression joints it always seems a bit kind-of hit
and miss and they seem to need to be VERY tight to not leak - so
tight I worry about damaging the joint or pipe.

I normally put grease on the threads which makes them easier to
tighten but of course doesn't reduce the pressure on the parts..

After fitting a radiator the screw cap had started to crack after it
was leaking a tiny bit and I tightened it some more. So I'm wondering
if I'm doing something wrong, perhaps the pipe should be pulled out a
little bit from the joint before tightening? or anything else?

Also are the silver joints stronger than gold ones?

In my limited experience compression joints leak if

a) the pipe isn't 100% aligned with the fitting, i.e. approaching at a
slight angle.
b) the pipe isn't fully pushed into the fitting. Sometimes difficult
to keep it pushed in when both hands are holding spanners.
c) the cut isn't made with a proper pipe cutter

I'd totally agee with Stuart. Given you heed his advise above, they don't
need to be as tight as you describe to seal.


--
Dave - The Medway Handyman
www.medwayhandyman.co.uk

On Sat, 11 Oct 2008 18:47:15 +0000, The Medway Handyman wrote:

stuart noble wrote:
405 TD Estate wrote:
When tightening compression joints it always seems a bit kind-of hit
and miss and they seem to need to be VERY tight to not leak - so tight
I worry about damaging the joint or pipe.

I normally put grease on the threads which makes them easier to
tighten but of course doesn't reduce the pressure on the parts..

After fitting a radiator the screw cap had started to crack after it
was leaking a tiny bit and I tightened it some more. So I'm wondering
if I'm doing something wrong, perhaps the pipe should be pulled out a
little bit from the joint before tightening? or anything else?

Also are the silver joints stronger than gold ones?

In my limited experience compression joints leak if

a) the pipe isn't 100% aligned with the fitting, i.e. approaching at a
slight angle.
b) the pipe isn't fully pushed into the fitting. Sometimes difficult to
keep it pushed in when both hands are holding spanners. c) the cut
isn't made with a proper pipe cutter

I'd totally agee with Stuart. Given you heed his advise above, they
don't need to be as tight as you describe to seal.

Agreed, a tiny smear of a suitable jointing compound also help a lot.


--
Ed Sirett - Property maintainer and registered gas fitter.
The FAQ for uk.diy is at http://www.diyfaq.org.uk
Gas fitting FAQ http://www.makewrite.demon.co.uk/GasFitting.html
Sealed CH FAQ http://www.makewrite.demon.co.uk/SealedCH.html
Choosing a Boiler FAQ http://www.makewrite.demon.co.uk/BoilerChoice.html

Jointing compound - on the olive or threads?

"Ed Sirett" wrote in message
...
On Sat, 11 Oct 2008 18:47:15 +0000, The Medway Handyman wrote:

stuart noble wrote:
405 TD Estate wrote:
When tightening compression joints it always seems a bit kind-of hit
and miss and they seem to need to be VERY tight to not leak - so tight
I worry about damaging the joint or pipe.

I normally put grease on the threads which makes them easier to
tighten but of course doesn't reduce the pressure on the parts..

After fitting a radiator the screw cap had started to crack after it
was leaking a tiny bit and I tightened it some more. So I'm wondering
if I'm doing something wrong, perhaps the pipe should be pulled out a
little bit from the joint before tightening? or anything else?

Also are the silver joints stronger than gold ones?

In my limited experience compression joints leak if

a) the pipe isn't 100% aligned with the fitting, i.e. approaching at a
slight angle.
b) the pipe isn't fully pushed into the fitting. Sometimes difficult to
keep it pushed in when both hands are holding spanners. c) the cut
isn't made with a proper pipe cutter

I'd totally agee with Stuart. Given you heed his advise above, they
don't need to be as tight as you describe to seal.

Agreed, too.

To add some mo

The pipe ought to be clean, free from scratches / gouges, and properly
round.
The olive ought to be able to slide up and down freely, but not loosely.

With the pipe in the fitting, it ought to be possible to do up the nut right
up to the olive by hand. It should then only take a gentle nip up with a
spanner.


Problems can be:
Over-tightening in the first instance ( a possibility from your
description );
Poor condition pipe ( deeply scratched, painted, ovaled out from mis-use or
impropper cutting ).
Pipe entering at an angle as already mentioned. Allow the pipe to be as
free to move side-ways as possible, so it can find a natural alignment.

If you want to use any sealing compound, it ought to go on the sealing
element ( the olive ) rather than the thread. The thread is not the
sealing element in a compression fitting.


--
Ron

If you want to use any sealing compound, it ought to go on the sealing
element ( the olive ) rather than the thread. The thread is not the
sealing element in a compression fitting.


But some lubrication on the thread always helps too, especially on some
fittings where the thread seems to be a bit "rough".
I usually put a smear of compound under and on the olive, then on the
thread.

A

On Sat, 11 Oct 2008 21:25:06 +0100, Andy Dee wrote:




If you want to use any sealing compound, it ought to go on the sealing
element ( the olive ) rather than the thread. The thread is not the
sealing element in a compression fitting.


But some lubrication on the thread always helps too, especially on some
fittings where the thread seems to be a bit "rough".
I usually put a smear of compound under and on the olive, then on the
thread.

And a "Wee drop of embalming fluid" behind the ears ?

Derek.

"Derek Geldard" wrote in message
...
On Sat, 11 Oct 2008 21:25:06 +0100, Andy Dee wrote:




If you want to use any sealing compound, it ought to go on the sealing
element ( the olive ) rather than the thread. The thread is not the
sealing element in a compression fitting.


But some lubrication on the thread always helps too, especially on some
fittings where the thread seems to be a bit "rough".
I usually put a smear of compound under and on the olive, then on the
thread.

And a "Wee drop of embalming fluid" behind the ears ?

Derek.


Cleanliness and a bit of lubrication. No PTFE tape.

John wrote:
"Derek Geldard" wrote in message
...
On Sat, 11 Oct 2008 21:25:06 +0100, Andy Dee wrote:


If you want to use any sealing compound, it ought to go on the sealing
element ( the olive ) rather than the thread. The thread is not the
sealing element in a compression fitting.


But some lubrication on the thread always helps too, especially on some
fittings where the thread seems to be a bit "rough".
I usually put a smear of compound under and on the olive, then on the
thread.
And a "Wee drop of embalming fluid" behind the ears ?

Derek.


Cleanliness and a bit of lubrication. No PTFE tape.

You can use the PTFE for a bit of lubrication...

--
Cheers,

John.

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

On Oct 11, 10:33*pm, John Rumm wrote:
Cleanliness and a bit of lubrication. No PTFE tape.

You can use the PTFE for a bit of lubrication...

Where does the PFTE go? I love seeing ptfe just sneaking out of the
nut of a compression joint! Thats enough to put smile on the face of
any miserable plumber! Even a friendly builder I know does that, bless
his cotton socks

I read this thread with interest and the idea of putting lubrication
on the threads is hogwash! I've done thousands of compressions and
never needed to! So what if they squeak a bit?
I agree with a smear of compound of your choice on the water facing
part of the olive *only*. Many people say no compound, but it saves
dismantling later on a weeping joint so is a worthwhile precaution in
my mind.

But please - no ptfte tape on threads, ever!

In article
,
405 TD Estate wrote:
When tightening compression joints it always seems a bit kind-of hit
and miss and they seem to need to be VERY tight to not leak - so tight
I worry about damaging the joint or pipe.

I normally put grease on the threads which makes them easier to
tighten but of course doesn't reduce the pressure on the parts..

After fitting a radiator the screw cap had started to crack after it
was leaking a tiny bit and I tightened it some more. So I'm wondering
if I'm doing something wrong, perhaps the pipe should be pulled out a
little bit from the joint before tightening? or anything else?

You must be using enormous torque to damage a 15mm compression fitting.

If you have leaks after normal tightening, something is wrong.

Is the pipe clean, round, straight and free from bad scratches?
Is it going fully into the fitting?
Are you using good quality fittings?

A lick of Fernox LS-X silicone sealer round the olive before tightening
won't harm - but really shouldn't be needed.

--
*Honk if you love peace and quiet*

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

Andy Dee wrote:
If you want to use any sealing compound, it ought to go on the
sealing element ( the olive ) rather than the thread. The thread
is not the sealing element in a compression fitting.


But some lubrication on the thread always helps too, especially on
some fittings where the thread seems to be a bit "rough".
I usually put a smear of compound under and on the olive, then on the
thread.

I've found that 'rough' thread on some makes of compression fittings, oddly
enough mainly on the ones from my local plumbing supplies place. TBH I find
that Wickes compresion fittings are the best.

I use 2 turns of PTFE tape as a lubricant.



--
Dave - The Medway Handyman
www.medwayhandyman.co.uk



--
Dave - The Medway Handyman
www.medwayhandyman.co.uk

Dave Starling wrote:
On Oct 11, 10:33 pm, John Rumm wrote:
Cleanliness and a bit of lubrication. No PTFE tape.

You can use the PTFE for a bit of lubrication...

Where does the PFTE go? I love seeing ptfe just sneaking out of the
nut of a compression joint! Thats enough to put smile on the face of
any miserable plumber! Even a friendly builder I know does that, bless
his cotton socks

I read this thread with interest and the idea of putting lubrication
on the threads is hogwash! I've done thousands of compressions and
never needed to! So what if they squeak a bit?
I agree with a smear of compound of your choice on the water facing
part of the olive *only*. Many people say no compound, but it saves
dismantling later on a weeping joint so is a worthwhile precaution in
my mind.

But please - no ptfe tape on threads, ever!

Flame suit on

I usually buy compression fittngs from Wickes or Screwfix, which ever is
nearest, no problems with either. The last lot I bought to re stock the van
were from a local plumbing supplies place and they are a PITA as well as
being more expensive.

No idea of specific manufacturers, but they obviously do vary.

PTFE tape is a great thread lubricant! The compresion fittings from my
local plumbing supplies place simply wouldn't do up tight enough without
PTFE tape lubrication.


--
Dave - The Medway Handyman
www.medwayhandyman.co.uk

We were somewhere around Barstow, on the edge of the desert, when the
drugs began to take hold. I remember "Ron Lowe"
ronATlowe-famlyDOTmeDOTukSPURIOUS saying something like:

With the pipe in the fitting, it ought to be possible to do up the nut right
up to the olive by hand. It should then only take a gentle nip up with a
spanner.

Depends what you mean by that. Your 'gentle nip up' might actually mean
a good quarter turn or more. Most people's 'nip up' would leave it prone
to loosening off.
--
Dave
GS850x2 XS650 SE6a

"It's a moron working with power tools.
How much more suspenseful can you get?"
- House

In article ,
John wrote:
Cleanliness and a bit of lubrication. No PTFE tape.

It shouldn't be needed but will do no harm.

--
*Why is the word abbreviation so long?

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

I haven't been cleaning the pipe as i would for a soldered joint -
maybe that's it?

Also some of the pipe's are slightly mis-aligned - maybe that's it?

Kinda wishing I'd taken the chrome off a bit of the pipes and soldered
the things. I guess you guys find soldered joints a lot more reliable
as well...? There again I don't know how round the pipe would be after
I file the chrome off..

405 TD Estate wrote:
I haven't been cleaning the pipe as i would for a soldered joint -
maybe that's it?

Also some of the pipe's are slightly mis-aligned - maybe that's it?

Kinda wishing I'd taken the chrome off a bit of the pipes and soldered
the things. I guess you guys find soldered joints a lot more reliable
as well...? There again I don't know how round the pipe would be after
I file the chrome off..

Chrome pipe is a slightly different ball game - it tends to need a more
serious doing up to get a good seal IME.

--
Cheers,

John.

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

On Sat, 11 Oct 2008 23:13:01 +0000, The Medway Handyman wrote:

Dave Starling wrote:
On Oct 11, 10:33 pm, John Rumm wrote:
Cleanliness and a bit of lubrication. No PTFE tape.

You can use the PTFE for a bit of lubrication...

Where does the PFTE go? I love seeing ptfe just sneaking out of the nut
of a compression joint! Thats enough to put smile on the face of any
miserable plumber! Even a friendly builder I know does that, bless his
cotton socks

I read this thread with interest and the idea of putting lubrication on
the threads is hogwash! I've done thousands of compressions and never
needed to! So what if they squeak a bit? I agree with a smear of
compound of your choice on the water facing part of the olive *only*.
Many people say no compound, but it saves dismantling later on a
weeping joint so is a worthwhile precaution in my mind.

But please - no ptfe tape on threads, ever!

Flame suit on

I usually buy compression fittngs from Wickes or Screwfix, which ever is
nearest, no problems with either. The last lot I bought to re stock the
van were from a local plumbing supplies place and they are a PITA as
well as being more expensive.

No idea of specific manufacturers, but they obviously do vary.

Since the joints are supposed to be manufactured to BS 864 (or it's EN
equivalent) they /ought/ to be reasonably similar.

However there are several options:
1)The manufactuers are not holding to the standard.
2) The standard allows for a tolerance band.
3) Some of the fittings are not to BS 864 just supposedly good enough.

I tend not to used anything on the threads or if I'm using silicone
greases for the olive I might put a little on the threads. However the
latter make the tightening more 'squeaky' IME. PTFE removes the
squeakiness in the tightening but will make the joints slightly harder to
do up.


--
Ed Sirett - Property maintainer and registered gas fitter.
The FAQ for uk.diy is at http://www.diyfaq.org.uk
Gas fitting FAQ http://www.makewrite.demon.co.uk/GasFitting.html
Sealed CH FAQ http://www.makewrite.demon.co.uk/SealedCH.html
Choosing a Boiler FAQ http://www.makewrite.demon.co.uk/BoilerChoice.html

On Sat, 11 Oct 2008 19:00:12 -0700, 405 TD Estate wrote:

I haven't been cleaning the pipe as i would for a soldered joint - maybe
that's it?

That's over the top,but clean so that pipe is smooth is needed.


Also some of the pipe's are slightly mis-aligned - maybe that's it?

A small amount of misalignment is possible, some olives are better than
others in this area.


Kinda wishing I'd taken the chrome off a bit of the pipes and soldered
the things. I guess you guys find soldered joints a lot more reliable as
well...? There again I don't know how round the pipe would be after I
file the chrome off..

I'd definitely leave the chrome on and use a little resin (LS-X, Loctite
thread seal, etc) on the oilve/chamfer part.


--
Ed Sirett - Property maintainer and registered gas fitter.
The FAQ for uk.diy is at http://www.diyfaq.org.uk
Gas fitting FAQ http://www.makewrite.demon.co.uk/GasFitting.html
Sealed CH FAQ http://www.makewrite.demon.co.uk/SealedCH.html
Choosing a Boiler FAQ http://www.makewrite.demon.co.uk/BoilerChoice.html

I've never really looked at it systematically but I wonder whether
some olives are better than others, where 'better' might be 'softer',
so more likely to seat in the fitting. I just did a complicated
little run that I built up on the bench (fresh pipe, no alignment
issues, plenty of access to tighten everything) then installed and it
leaked in about half the joints. Took it off and recycled most of the
pipe and all of the fittings but, obviously, had to use fresh olives -
every joint was a good 'un. If I knew where I got that pack of olives
(probably Screwfix), I'd get some more while they're still on the same
batch!

On the other hand, it might have been a 'good day/bad day' thing and
nothing to do with the olives......

In article ,
Ed Sirett wrote:
No idea of specific manufacturers, but they obviously do vary.

Since the joints are supposed to be manufactured to BS 864 (or it's EN
equivalent) they /ought/ to be reasonably similar.

However there are several options:
1)The manufactuers are not holding to the standard.
2) The standard allows for a tolerance band.
3) Some of the fittings are not to BS 864 just supposedly good enough.

I've seen fittings with damage to the tapers. Dunno how much the BS majors
on quality control.

--
*I'm not being rude. You're just insignificant

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

On Oct 12, 1:26*am, "Dave Plowman (News)"
wrote:
In article ,
* *John wrote:

Cleanliness and a bit of lubrication. No PTFE tape.

It shouldn't be needed but will do no harm.

--
*Why is the word abbreviation so long?

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

when cleaning the tube I use steel wool and a rub it 'round and round'
rather than 'up and down' so there are no 'channels' scratched into
the tube surface. Much as if I was doing a soldered joint. perhaps
this is overkill.

Robert

In article
,
RobertL wrote:
when cleaning the tube I use steel wool and a rub it 'round and round'
rather than 'up and down' so there are no 'channels' scratched into
the tube surface. Much as if I was doing a soldered joint. perhaps
this is overkill.

Just for information you can get cleaner strips these days that are faster
than wire wool - and no sharp bits to pierce the skin. They seem quite
expensive - but have a long life. I won't use anything else now. Also
makes cleaning the back of a pipe in a tricky place easy.

However neither method should produce scratches deep enough to cause
problems - and 'round' the pipe is the natural way to clean it.

--
*Indian Driver - Smoke signals only*

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

Dave Plowman (News) wrote:
In article
,
RobertL wrote:
when cleaning the tube I use steel wool and a rub it 'round and
round' rather than 'up and down' so there are no 'channels'
scratched into the tube surface. Much as if I was doing a soldered
joint. perhaps this is overkill.

I also clean the pipe prior to using a compression fitting, don't think its
overkill at all.

Just for information you can get cleaner strips these days that are
faster than wire wool - and no sharp bits to pierce the skin. They
seem quite expensive - but have a long life. I won't use anything
else now. Also makes cleaning the back of a pipe in a tricky place
easy.

I use those & find them really good, if the end of the pipe is accessable I
use one of these
http://www.wickes.co.uk/Plumbing-Too...ol/invt/159884


--
Dave - The Medway Handyman
www.medwayhandyman.co.uk

The message

from GMM contains these words:

Took it off and recycled most of the
pipe and all of the fittings but, obviously, had to use fresh olives -
every joint was a good 'un. If I knew where I got that pack of olives
(probably Screwfix), I'd get some more while they're still on the same
batch!

Conex ones are particularly good, IMHO