I have a situation where I have isolating valves and check valves with compression fittings in close proximity and keep getting a slight weep tightening the compression fittings simply causes problems with the next fitting as tightening it loosens the one below especially when trying to keep the isolating valve orientation correct. So the question is can joint sealants like Boss White be used on potable water?

I need to sort the issue out quick as it is holding up the sink installation after which access becomes more difficult and Christmas dinner is at stake.

Richard

On 23/12/2020 13:32, Tricky Dicky wrote:
I have a situation where I have isolating valves and check valves with compression fittings in close proximity and keep getting a slight weep tightening the compression fittings simply causes problems with the next fitting as tightening it loosens the one below especially when trying to keep the isolating valve orientation correct. So the question is can joint sealants like Boss White be used on potable water?

I need to sort the issue out quick as it is holding up the sink installation after which access becomes more difficult and Christmas dinner is at stake.

Richard

I'm 99% sure that Boss White is rated for potable water, but surely it
will say so on the tin or tube.

Traditionally Boss White was used with hemp (although it can be used alone).

These days I tend to use the various PTFE-based thread sealants
available from SF and TS (but seldom have issues for potable water so
don't usually worry about that). Less messy and easier to dismantle than
Boss White type products.

GIYF

https://www.amazon.co.uk/Loctite-pro...Instant%20seal.

On Wednesday, 23 December 2020 at 13:53:32 UTC, newshound wrote:
On 23/12/2020 13:32, Tricky Dicky wrote:
I have a situation where I have isolating valves and check valves with compression fittings in close proximity and keep getting a slight weep tightening the compression fittings simply causes problems with the next fitting as tightening it loosens the one below especially when trying to keep the isolating valve orientation correct. So the question is can joint sealants like Boss White be used on potable water?

I need to sort the issue out quick as it is holding up the sink installation after which access becomes more difficult and Christmas dinner is at stake.

Richard

I'm 99% sure that Boss White is rated for potable water, but surely it
will say so on the tin or tube.

Traditionally Boss White was used with hemp (although it can be used alone).

These days I tend to use the various PTFE-based thread sealants
available from SF and TS (but seldom have issues for potable water so
don't usually worry about that). Less messy and easier to dismantle than
Boss White type products.

GIYF

https://www.amazon.co.uk/Loctite-pro...Instant%20seal.
Thanks Newshound Boss White is out but Fernox do one for potable water just ordered it at SF

Richard

On 23/12/2020 14:23, Tricky Dicky wrote:
On Wednesday, 23 December 2020 at 13:53:32 UTC, newshound wrote:
On 23/12/2020 13:32, Tricky Dicky wrote:
I have a situation where I have isolating valves and check valves with compression fittings in close proximity and keep getting a slight weep tightening the compression fittings simply causes problems with the next fitting as tightening it loosens the one below especially when trying to keep the isolating valve orientation correct. So the question is can joint sealants like Boss White be used on potable water?

I need to sort the issue out quick as it is holding up the sink installation after which access becomes more difficult and Christmas dinner is at stake.

Richard

I'm 99% sure that Boss White is rated for potable water, but surely it
will say so on the tin or tube.

Traditionally Boss White was used with hemp (although it can be used alone).

These days I tend to use the various PTFE-based thread sealants
available from SF and TS (but seldom have issues for potable water so
don't usually worry about that). Less messy and easier to dismantle than
Boss White type products.

GIYF

https://www.amazon.co.uk/Loctite-pro...Instant%20seal.
Thanks Newshound Boss White is out but Fernox do one for potable water just ordered it at SF

Richard



Are you talking about their LSX, or the jointing compound?

On 23/12/2020 13:32, Tricky Dicky wrote:

I have a situation where I have isolating valves and check valves
with compression fittings in close proximity and keep getting a
slight weep tightening the compression fittings simply causes
problems with the next fitting as tightening it loosens the one below
especially when trying to keep the isolating valve orientation
correct. So the question is can joint sealants like Boss White be
used on potable water?

No - non potable only. Boss green / supergreen is the one designed for
potable / wholesome water applications.

However it sounds like all you need is a spanner to hold the body of the
fitting in place while you tighten the nuts.

I need to sort the issue out quick as it is holding up the sink
installation after which access becomes more difficult and Christmas
dinner is at stake.




--
Cheers,

John.

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

On 23/12/2020 13:53, newshound wrote:
On 23/12/2020 13:32, Tricky Dicky wrote:
I have a situation where I have isolating valves and check valves
with compression fittings in close proximity and keep getting a
slight weep tightening the compression fittings simply causes
problems with the next fitting as tightening it loosens the one
below especially when trying to keep the isolating valve
orientation correct. So the question is can joint sealants like
Boss White be used on potable water?

I need to sort the issue out quick as it is holding up the sink
installation after which access becomes more difficult and
Christmas dinner is at stake.

Richard


I'm 99% sure that Boss White is rated for potable water,

No, that's the green version

but surely
it will say so on the tin or tube.

It does. "Boss White Jointing Compound - 400g Tub
A non-toxic jointing compound. Conforms to BS 6956-5:1992 for use with
hot and cold water (non-potable duties), Natural Gas and low pressure
steam up to 7 bar pressure and temperature up to 200°C."

Traditionally Boss White was used with hemp (although it can be used
alone).

You can't use hemp on potable supplies either (it can harbour microbial
growth). PTFE tape would be a more appropriate choice.

These days I tend to use the various PTFE-based thread sealants
available from SF and TS (but seldom have issues for potable water so
don't usually worry about that). Less messy and easier to dismantle
than Boss White type products.

GIYF

https://www.amazon.co.uk/Loctite-pro...Instant%20seal.

Fernox LSX is another silicone based sealer you can use.

--
Cheers,

John.

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

In article ,
Tricky Dicky wrote:
I have a situation where I have isolating valves and check valves with
compression fittings in close proximity and keep getting a slight weep
tightening the compression fittings simply causes problems with the next
fitting as tightening it loosens the one below

You need to stop pretty well any compression fitting from turning when you
tighten it.

--
*Can vegetarians eat animal crackers?

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

On 23 Dec 2020 at 15:57:25 GMT, ""Dave Plowman" News)"
wrote:

In article ,
Tricky Dicky wrote:
I have a situation where I have isolating valves and check valves with
compression fittings in close proximity and keep getting a slight weep
tightening the compression fittings simply causes problems with the next
fitting as tightening it loosens the one below

You need to stop pretty well any compression fitting from turning when you
tighten it.

If concerned about the bit of pipe between two compression fittings turning,
tighten on of them until it doesn't turn when you tighten the other.

--
Roger Hayter

Sealant on the treads is not the solution - the threads only provide a
clamping force. The olive forms the seal. Cleanliness is the most important
thing.

On 23/12/2020 18:37, JohnP wrote:


Sealant on the treads is not the solution - the threads only provide a
clamping force. The olive forms the seal. Cleanliness is the most important
thing.

Agreed, absolutely. But occasionally you end up with one joint that
weeps and where it would be a PITA to replace because of all the other
stuff connected to it. And then those PTFE goos are very useful.

It is also one of the reasons I usually use PTFE tape on the threads of
new compression fitting builds, because it reduces the friction so that
you get a better clamping load with less torque.

People always tell you not to put the tape over the olive, and I don't.
Although actually if you compare the strength of PTFE with even fully
annealed copper, you will find that a thin layer of PTFE will completely
extrude away from the metal to metal interface. The same is true of the
"knife edge" that you get where brass olives dig into a copper pipe.
PTFE tape there is *not* going to prevent you from getting a seal.

But, in a bodge, it's always possible for tape to trap grit at the
sealing location and make things worse.

On 23/12/2020 14:32, John Rumm wrote:
On 23/12/2020 13:53, newshound wrote:
On 23/12/2020 13:32, Tricky Dicky wrote:
I have a situation where I have isolating valves and check valves
with compression fittings in close proximity and keep getting a
slight weep tightening the compression fittings simply causes
problems with the next fitting as tightening it loosens the one
below especially when trying to keep the isolating valve
orientation correct. So the question is can joint sealants like
Boss White be used on potable water?

I need to sort the issue out quick as it is holding up the sink
installation after which access becomes more difficult and
Christmas dinner is at stake.

Richard


I'm 99% sure that Boss White is rated for potable water,

No, that's the green version


My bad, it is a very long time since I used it. My first house (in the
70's) had quite a bit of iron pipe in places, so I did end up using hemp
and Boss White at times.

I still keep a reel of the Loctite "dental floss" (which I think might
be Kevlar) in my "heavy" plumbing tool kit for taper threads. But that
works fine used "dry".

In article ,
newshound wrote:
On 23/12/2020 18:37, JohnP wrote:


Sealant on the treads is not the solution - the threads only provide a
clamping force. The olive forms the seal. Cleanliness is the most important
thing.

Agreed, absolutely. But occasionally you end up with one joint that
weeps and where it would be a PITA to replace because of all the other
stuff connected to it. And then those PTFE goos are very useful.

It is also one of the reasons I usually use PTFE tape on the threads of
new compression fitting builds, because it reduces the friction so that
you get a better clamping load with less torque.

People always tell you not to put the tape over the olive, and I don't.
Although actually if you compare the strength of PTFE with even fully
annealed copper, you will find that a thin layer of PTFE will completely
extrude away from the metal to metal interface. The same is true of the
"knife edge" that you get where brass olives dig into a copper pipe.
PTFE tape there is *not* going to prevent you from getting a seal.

But, in a bodge, it's always possible for tape to trap grit at the
sealing location and make things worse.

I was taught to put tape over the olive. It seesm to work - even 40 years
later.

--
from KT24 in Surrey, England
"I'd rather die of exhaustion than die of boredom" Thomas Carlyle

charles wrote:
In article ,
newshound wrote:
On 23/12/2020 18:37, JohnP wrote:


Sealant on the treads is not the solution - the threads only provide a
clamping force. The olive forms the seal. Cleanliness is the most important
thing.

Agreed, absolutely. But occasionally you end up with one joint that
weeps and where it would be a PITA to replace because of all the other
stuff connected to it. And then those PTFE goos are very useful.

It is also one of the reasons I usually use PTFE tape on the threads of
new compression fitting builds, because it reduces the friction so that
you get a better clamping load with less torque.

People always tell you not to put the tape over the olive, and I don't.
Although actually if you compare the strength of PTFE with even fully
annealed copper, you will find that a thin layer of PTFE will completely
extrude away from the metal to metal interface. The same is true of the
"knife edge" that you get where brass olives dig into a copper pipe.
PTFE tape there is *not* going to prevent you from getting a seal.

But, in a bodge, it's always possible for tape to trap grit at the
sealing location and make things worse.

I was taught to put tape over the olive. It seesm to work - even 40 years
later.

I guess, as in the thread, it acts as a lubricant, The nut has to
rotate against the olive so some lubricant doesn't go amiss. I do
wonder if grease or a lubricant spray of some sort might be as
effective.

--
Chris Green
·

On 23/12/2020 13:32, Tricky Dicky wrote:
I have a situation where I have isolating valves and check valves with compression fittings in close proximity and keep getting a slight weep tightening the compression fittings simply causes problems with the next fitting as tightening it loosens the one below especially when trying to keep the isolating valve orientation correct. So the question is can joint sealants like Boss White be used on potable water?

I need to sort the issue out quick as it is holding up the sink installation after which access becomes more difficult and Christmas dinner is at stake.

Richard



Valves usually have a couple of flats on the body so that you can stop
them turning with a spanner or hold the body with a pipe wrench or water
pump pliers.

Maybe the pipe entering the isolating/check values is not truly on axis
which tends to make the nut on the compression fitting bind on the side
of the pipe when tightening up rather than being easy to turn until the
last 1/4 to 1/2 turn which tightens it. The other possibility for a
weeping compression is that the pipe was not fully seated into the
fitting before initially tightening.

Perhaps on your weeping compression fittings remove the pipe. Is the
olive still loose? Is the olive at the very end of the pipe rather than
10mm+ down the pipe.

--
mailto : news {at} admac {dot} myzen {dot} co {dot} uk

On Wednesday, 23 December 2020 at 21:11:00 UTC, alan_m wrote:
On 23/12/2020 13:32, Tricky Dicky wrote:
I have a situation where I have isolating valves and check valves with compression fittings in close proximity and keep getting a slight weep tightening the compression fittings simply causes problems with the next fitting as tightening it loosens the one below especially when trying to keep the isolating valve orientation correct. So the question is can joint sealants like Boss White be used on potable water?

I need to sort the issue out quick as it is holding up the sink installation after which access becomes more difficult and Christmas dinner is at stake.

Richard

Valves usually have a couple of flats on the body so that you can stop
them turning with a spanner or hold the body with a pipe wrench or water
pump pliers.

Maybe the pipe entering the isolating/check values is not truly on axis
which tends to make the nut on the compression fitting bind on the side
of the pipe when tightening up rather than being easy to turn until the
last 1/4 to 1/2 turn which tightens it. The other possibility for a
weeping compression is that the pipe was not fully seated into the
fitting before initially tightening.

Perhaps on your weeping compression fittings remove the pipe. Is the
olive still loose? Is the olive at the very end of the pipe rather than
10mm+ down the pipe.

--
mailto : news {at} admac {dot} myzen {dot} co {dot} uk
I went back to the start and the issue is solved. When I realised that a compression 15mm adaptor, an isolator and a check valve all in the space of about 250mm, I realised I might encounter some of the problems so I originally assembled the two assemblies on the bench before putting them in situ. The hot water one proved unproblematic but as posted the cold proved problematic and Sods law it was the nuts on the isolator and the check valve just below that seeped. I did grip the isolator with mole grips while tightening the compression joints but the effect was that as I tightened one the next one loosened. Anyway took the assembly apart retightened all the compression joints on the bench giving each a smear of the Feronox potable water sealant for good measure, reassembled the the whole thing in situ gripping the check valve across some slight flats with the mole grips whilst tightening the lowest compression joint and problem solved. Probably going back to the bench was the crucial task with Feronox sealant as belt and braces. So thanks to all respondents. Christmas dinner is still in the balance, faffing around with the fittings and an unscheduled trip to SF meant I did not get the sink done, so I have tomorrow to drop the worktop in place and fit the sink in but with everything in place and prepared tomorrow should see that done barring any unforeseen issues now I just hope I have not offended the gods of DIY!

Thanks again to all
Richard

On 23/12/2020 20:26, charles wrote:
In article ,
newshound wrote:
On 23/12/2020 18:37, JohnP wrote:


Sealant on the treads is not the solution - the threads only provide a
clamping force. The olive forms the seal. Cleanliness is the most important
thing.

Agreed, absolutely. But occasionally you end up with one joint that
weeps and where it would be a PITA to replace because of all the other
stuff connected to it. And then those PTFE goos are very useful.

It is also one of the reasons I usually use PTFE tape on the threads of
new compression fitting builds, because it reduces the friction so that
you get a better clamping load with less torque.

People always tell you not to put the tape over the olive, and I don't.
Although actually if you compare the strength of PTFE with even fully
annealed copper, you will find that a thin layer of PTFE will completely
extrude away from the metal to metal interface. The same is true of the
"knife edge" that you get where brass olives dig into a copper pipe.
PTFE tape there is *not* going to prevent you from getting a seal.

But, in a bodge, it's always possible for tape to trap grit at the
sealing location and make things worse.

I was taught to put tape over the olive. It seesm to work - even 40 years
later.

Plumbers are, in the main, pretty ****ing stupid.

When I got one to install my *mains pressure* 2.1 bar regulated
cylinder, in the loft he nodded approvingly "That will giver you better
water pressure"

I can confirm that ptfe does nothing and sometimes makes things worse


--
"In our post-modern world, climate science is not powerful because it is
true: it is true because it is powerful."

Lucas Bergkamp

PTFE tape has seemingly fixed most of my compression fitting issues for over
20 years now!

I'm still alive too!
Brian

--

This newsgroup posting comes to you directly from...
The Sofa of Brian Gaff...

Blind user, so no pictures please
Note this Signature is meaningless.!
"newshound" wrote in message
o.uk...
On 23/12/2020 13:32, Tricky Dicky wrote:
I have a situation where I have isolating valves and check valves with
compression fittings in close proximity and keep getting a slight weep
tightening the compression fittings simply causes problems with the next
fitting as tightening it loosens the one below especially when trying to
keep the isolating valve orientation correct. So the question is can
joint sealants like Boss White be used on potable water?

I need to sort the issue out quick as it is holding up the sink
installation after which access becomes more difficult and Christmas
dinner is at stake.

Richard

I'm 99% sure that Boss White is rated for potable water, but surely it
will say so on the tin or tube.

Traditionally Boss White was used with hemp (although it can be used
alone).

These days I tend to use the various PTFE-based thread sealants available
from SF and TS (but seldom have issues for potable water so don't usually
worry about that). Less messy and easier to dismantle than Boss White type
products.

GIYF

https://www.amazon.co.uk/Loctite-pro...Instant%20seal.

On 23/12/2020 22:14, Tricky Dicky wrote:

On Wednesday, 23 December 2020 at 21:11:00 UTC, alan_m wrote:

On 23/12/2020 13:32, Tricky Dicky wrote:

I have a situation where I have isolating valves and check valves with compression fittings in close proximity and keep getting a slight weep tightening the compression fittings simply causes problems with the next fitting as tightening it loosens the one below especially when trying to keep the isolating valve orientation correct. So the question is can joint sealants like Boss White be used on potable water?

I need to sort the issue out quick as it is holding up the sink installation after which access becomes more difficult and Christmas dinner is at stake.

Richard


Valves usually have a couple of flats on the body so that you can stop
them turning with a spanner or hold the body with a pipe wrench or water
pump pliers.

Maybe the pipe entering the isolating/check values is not truly on axis
which tends to make the nut on the compression fitting bind on the side
of the pipe when tightening up rather than being easy to turn until the
last 1/4 to 1/2 turn which tightens it. The other possibility for a
weeping compression is that the pipe was not fully seated into the
fitting before initially tightening.

Perhaps on your weeping compression fittings remove the pipe. Is the
olive still loose? Is the olive at the very end of the pipe rather than
10mm+ down the pipe.

--
mailto : news {at} admac {dot} myzen {dot} co {dot} uk

I went back to the start and the issue is solved. When I realised that a compression 15mm adaptor, an isolator and a check valve all in the space of about 250mm, I realised I might encounter some of the problems so I originally assembled the two assemblies on the bench before putting them in situ. The hot water one proved unproblematic but as posted the cold proved problematic and Sods law it was the nuts on the isolator and the check valve just below that seeped. I did grip the isolator with mole grips while tightening the compression joints but the effect was that as I tightened one the next one loosened. Anyway took the assembly apart retightened all the compression joints on the bench giving each a smear of the Feronox potable water sealant for good measure, reassembled the the whole thing in situ gripping the check valve across some slight flats with the mole grips whilst tightening the lowest compression joint and problem solved. Probably going back to the bench was the crucial task with Feronox sealant as belt and braces. So thanks to all respondents. Christmas dinner is still in the balance, faffing around with the fittings and an unscheduled trip to SF meant I did not get the sink done, so I have tomorrow to drop the worktop in place and fit the sink in but with everything in place and prepared tomorrow should see that done barring any unforeseen issues now I just hope I have not offended the gods of DIY!

Thanks again to all
Richard


Glad it is solved. Often a problem with several bits in series,
especially with limited space. I have quite a collection of adjustables,
water pump spanners, strap wrenches, and mole wrenches that cover most
eventualities. Sometimes an extra pair of hands to hold something "down
the chain" helps. There's also an element of "feel" that recognises when
something unintended has moved. As you have discovered, sealants give
you a bit of margin. Also, for cold water and DHW any very tiny weeps,
perhaps only showing up as a damp spot, usually seal themselves quite
quickly with lime deposits.

On 23/12/2020 13:32, Tricky Dicky wrote:
I have a situation where I have isolating valves and check valves with compression fittings in close proximity and keep getting a slight weep tightening the compression fittings simply causes problems with the next fitting as tightening it loosens the one below especially when trying to keep the isolating valve orientation correct. So the question is can joint sealants like Boss White be used on potable water?

I need to sort the issue out quick as it is holding up the sink installation after which access becomes more difficult and Christmas dinner is at stake.

Richard


I always add PTFE tape to compression joints after first tightening
these days. Quality of fittings just aint what it used to be!

Mike

In article ,
charles wrote:
In article ,
newshound wrote:
On 23/12/2020 18:37, JohnP wrote:


Sealant on the treads is not the solution - the threads only provide
a clamping force. The olive forms the seal. Cleanliness is the most
important thing.

Agreed, absolutely. But occasionally you end up with one joint that
weeps and where it would be a PITA to replace because of all the other
stuff connected to it. And then those PTFE goos are very useful.

It is also one of the reasons I usually use PTFE tape on the threads
of new compression fitting builds, because it reduces the friction so
that you get a better clamping load with less torque.

People always tell you not to put the tape over the olive, and I
don't. Although actually if you compare the strength of PTFE with
even fully annealed copper, you will find that a thin layer of PTFE
will completely extrude away from the metal to metal interface. The
same is true of the "knife edge" that you get where brass olives dig
into a copper pipe. PTFE tape there is *not* going to prevent you
from getting a seal.

But, in a bodge, it's always possible for tape to trap grit at the
sealing location and make things worse.

I was taught to put tape over the olive. It seesm to work - even 40
years later.

Absolutely. It may not be needed - but does no harm.

--
*Eagles may soar, but weasels don't get sucked into jet engines *

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

On 23/12/2020 14:27, John Rumm wrote:

snip

However it sounds like all you need is a spanner to hold the body of the
fitting in place while you tighten the nuts.

My thought too. Perhaps 3 spanners and 3 hands needed? Though you should
be able to work from one end to the other with just two, keeping the
last fitting or nut stationary.

On 23/12/2020 20:26, charles wrote:
In article ,
newshound wrote:
On 23/12/2020 18:37, JohnP wrote:


Sealant on the treads is not the solution - the threads only provide a
clamping force. The olive forms the seal. Cleanliness is the most important
thing.

Agreed, absolutely. But occasionally you end up with one joint that
weeps and where it would be a PITA to replace because of all the other
stuff connected to it. And then those PTFE goos are very useful.

It is also one of the reasons I usually use PTFE tape on the threads of
new compression fitting builds, because it reduces the friction so that
you get a better clamping load with less torque.

People always tell you not to put the tape over the olive, and I don't.
Although actually if you compare the strength of PTFE with even fully
annealed copper, you will find that a thin layer of PTFE will completely
extrude away from the metal to metal interface. The same is true of the
"knife edge" that you get where brass olives dig into a copper pipe.
PTFE tape there is *not* going to prevent you from getting a seal.

But, in a bodge, it's always possible for tape to trap grit at the
sealing location and make things worse.

I was taught to put tape over the olive. It seesm to work - even 40 years
later.

I was taught it was something only done by amateurs. It's doesn't help
seal but may lubricate the threads.
https://en.wikipedia.org/wiki/Compression_fitting

If you are going to use lubricant on the threads Jet-Lube V-2 Plus is a
potable lubricant.

In article ,
Fredxx wrote:
I was taught to put tape over the olive. It seesm to work - even 40 years
later.

I was taught it was something only done by amateurs. It's doesn't help
seal but may lubricate the threads.
https://en.wikipedia.org/wiki/Compression_fitting

Why would putting tape on the olive lubricate the threads?

If you are going to use lubricant on the threads Jet-Lube V-2 Plus is a
potable lubricant.

Why would you want lubricant on the threads? I've never managed to strip
them.

--
*A closed mouth gathers no feet.

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

On 24/12/2020 17:39, Dave Plowman (News) wrote:
In article ,
Fredxx wrote:
I was taught to put tape over the olive. It seesm to work - even 40 years
later.

I was taught it was something only done by amateurs. It's doesn't help
seal but may lubricate the threads.
https://en.wikipedia.org/wiki/Compression_fitting

Why would putting tape on the olive lubricate the threads?

If you are going to use lubricant on the threads Jet-Lube V-2 Plus is a
potable lubricant.

Why would you want lubricant on the threads? I've never managed to strip
them.

Because, by reducing friction at that point you get significantly more
axial force, which is what does the sealing, for a given torque. Also,
excess torque can disturb the next joint down the line, as discussed in
another thread. Same reason you were always taught to lubricate all the
studs and nuts when rebuilding a bottom end, so as to get the bearing
caps clamped down as well as possible.

On 24/12/2020 17:39, Dave Plowman (News) wrote:
In article ,
Fredxx wrote:
I was taught to put tape over the olive. It seesm to work - even 40 years
later.

I was taught it was something only done by amateurs. It's doesn't help
seal but may lubricate the threads.
https://en.wikipedia.org/wiki/Compression_fitting

Why would putting tape on the olive lubricate the threads?

Quite, and not sure why you think that. I advocate lubricant on the
threads. Perhaps a smear on the olive to allow the nut to turn.

If you are going to use lubricant on the threads Jet-Lube V-2 Plus is a
potable lubricant.

Why would you want lubricant on the threads? I've never managed to strip
them.

Something I have never achieved. They usually squeak and bind well
before then.

In article ,
newshound wrote:
Why would you want lubricant on the threads? I've never managed to strip
them.

Because, by reducing friction at that point you get significantly more
axial force, which is what does the sealing, for a given torque. Also,
excess torque can disturb the next joint down the line, as discussed in
another thread. Same reason you were always taught to lubricate all the
studs and nuts when rebuilding a bottom end, so as to get the bearing
caps clamped down as well as possible.

I've never had a problem tightening a compression fitting with dry
threads. With adequate sized spanners.

As regards an engine, you really need to know if the given torque setting
is clean and dry or lubricated. But such fixings are likely far more
critical torque wise than a compression fitting.

--
*I brake for no apparent reason.

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

In article ,
Fredxx wrote:
Something I have never achieved. They usually squeak and bind well
before then.

Yes - tighten until they groan. ;-)

--
*WHAT IF THERE WERE NO HYPOTHETICAL QUESTIONS?

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

On 24/12/2020 17:39, Dave Plowman (News) wrote:
In article ,
Fredxx wrote:
I was taught to put tape over the olive. It seesm to work - even 40 years
later.

I was taught it was something only done by amateurs. It's doesn't help
seal but may lubricate the threads.
https://en.wikipedia.org/wiki/Compression_fitting

Why would putting tape on the olive lubricate the threads?

It doesn't - but it might help create a seal if there is a very fine
scratch on the outside of the olive that is causing a slow leak.

If you are going to use lubricant on the threads Jet-Lube V-2 Plus is a
potable lubricant.

Why would you want lubricant on the threads? I've never managed to strip
them.

Mainly when you want to do up a fitting in a confined space and can only
get short spanners in there. You can then tighten them better with less
friction to fight.

(Jet lube also works - although is a tad more messy!)



--
Cheers,

John.

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

On 25/12/2020 11:04, Dave Plowman (News) wrote:
In article ,
newshound wrote:
Why would you want lubricant on the threads? I've never managed to strip
them.

Because, by reducing friction at that point you get significantly more
axial force, which is what does the sealing, for a given torque. Also,
excess torque can disturb the next joint down the line, as discussed in
another thread. Same reason you were always taught to lubricate all the
studs and nuts when rebuilding a bottom end, so as to get the bearing
caps clamped down as well as possible.

I've never had a problem tightening a compression fitting with dry
threads. With adequate sized spanners.

Indeed, try tightening the nuts on a 22mm butterfly valve in the gap
between the top of a kitchen cabinet and the ceiling, when the only
thing you can get in there is a pair of these:

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

(admittedly 17 years ago - but that was the last time I needed to use
PTFE on the threads to be able to get the nuts done up tight enough)



--
Cheers,

John.

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