Where to use PTFE tape - water connections
405 TD Estate
water tight but I have to tighten them up so much I worry I will break
the thread (though I haven't yet)
Also I assume you use plenty on threaded connections e.g. a TVR valve
into a radiator?
Andrew Gabriel
405 TD Estate <men...@yahoo.com> writes:
> Should I use PTFE tape on threaded olive connections? I can get then
> water tight but I have to tighten them up so much I worry I will break
> the thread (though I haven't yet)
PTFE should not be used anywhere near the sealing surfaces.
One layer on the sliding surfaces makes a good lubricant to
ease tightening them up -- that's the thread, and the back of
the olive, but not the front or inside of the olive.
If a compression fitting has failed and won't stop leaking
with appropiate tighening, the PTFE on the sealing surfaces
can sometimes make a reasonable bodge-it repair.
> Also I assume you use plenty on threaded connections e.g. a TVR valve
> into a radiator?
Yes. Radiators and tails vary, but I tended to start with 10
turns. If it screwed all the way home without getting tight,
dismantle, discard the used tape, and repeat with 12-15 turns.
--
Andrew Gabriel
[email address is not usable -- followup in the newsgroup]
Bob Mannix
news:4784c1eb$0$516$5a6a...@news.aaisp.net.uk...
> In article
> <7d855515-e463-4179...@i12g2000prf.googlegroups.com>,
> 405 TD Estate <men...@yahoo.com> writes:
>> Should I use PTFE tape on threaded olive connections? I can get then
>> water tight but I have to tighten them up so much I worry I will break
>> the thread (though I haven't yet)
>
> PTFE should not be used anywhere near the sealing surfaces.
> One layer on the sliding surfaces makes a good lubricant to
> ease tightening them up -- that's the thread, and the back of
> the olive, but not the front or inside of the olive.
I never put add anything anywhere near any compression fittings - just make
sure everything is clean, bright and undamaged - that is how they are
designed to be used
>
>> Also I assume you use plenty on threaded connections e.g. a TVR valve
>> into a radiator?
>
> Yes. Radiators and tails vary, but I tended to start with 10
> turns. If it screwed all the way home without getting tight,
> dismantle, discard the used tape, and repeat with 12-15 turns.
Indeed - I always do this even if it does tighten - fill the threads with
PTFE by screwing in, then remove, add more and make the final seal.
--
Bob Mannix
(anti-spam is as easy as 1-2-3 - not)
Mathew Newton
> Should I use PTFE tape on threaded olive connections? I can get then
> water tight but I have to tighten them up so much I worry I will break
> the thread (though I haven't yet)
It sounds like you might be overtighening them, resulting in a worse
seal (possibly through deformation).
My rule of thumb is to hand-tighten the nut then add half a turn with
the wrench (marking the nut/body can help if for some reason you need
to do this in two go's e.g. limited access).
Mathew
Andrew Gabriel
"Bob Mannix" <b1o...@mannix.org.uk> writes:
> "Andrew Gabriel" <and...@cucumber.demon.co.uk> wrote in message
> news:4784c1eb$0$516$5a6a...@news.aaisp.net.uk...
>> In article
>> <7d855515-e463-4179...@i12g2000prf.googlegroups.com>,
>> 405 TD Estate <men...@yahoo.com> writes:
>>> Should I use PTFE tape on threaded olive connections? I can get then
>>> water tight but I have to tighten them up so much I worry I will break
>>> the thread (though I haven't yet)
>>
>> PTFE should not be used anywhere near the sealing surfaces.
>> One layer on the sliding surfaces makes a good lubricant to
>> ease tightening them up -- that's the thread, and the back of
>> the olive, but not the front or inside of the olive.
>
> I never put add anything anywhere near any compression fittings - just make
> sure everything is clean, bright and undamaged - that is how they are
> designed to be used
In spite of what I said, I agree with you.
I've only used it on large compression fittings where
the librication was helpful. Never do this with gas
pipework though, as you wouldn't be able to prove
you hadn't got some PTFE into one of the seals.
Dave Liquorice
> Should I use PTFE tape on threaded olive connections?
No, compression joints should not require any thing other than finger
tight plus 1/2 to 3/4 of a turn. A smallest smear of something on the
inside of the nut to act as a lubricant is sometimes helpful.
> I can get then water tight but I have to tighten them up so much I worry
> I will break the thread (though I haven't yet)
Presumably 'cause you've got lots of PTFE stopping the olive bite the pipe
properly and seal against the fitting.
> Also I assume you use plenty on threaded connections e.g. a TVR valve
> into a radiator?
Cast iron and other parallel threaded stuff is about the only place to use
PTFE tape.
--
Cheers new...@howhill.com
Dave. pam is missing e-mail
diy-newby
"405 TD Estate" <men...@yahoo.com> wrote in message
news:7d855515-e463-4179...@i12g2000prf.googlegroups.com...
>
> Also I assume you use plenty on threaded connections e.g. a TVR valve
> into a radiator?
Is the TVR the sports version of the TRV ? :-)
Dave Baker
"diy-newby" <as...@asas.com> wrote in message news:fm2oq8$8pl$1...@aioe.org...
It's the one that bits drop off on a regular basis until it seizes up and
stops working. I think all of mine were like that when I bought the house
because none of them lasted long.
--
Dave Baker
Puma Race Engines
Roger Mills
PTFE tape is designed for use on tapered threaded connections - where the
seal has to be made within the threads. [When Adam were a lad, Boss White
and hemp did the same job - albeit a bit less tidily]. So you should
certainly use tape when screwing radiator valve tails into radiators.
You should *not* use it on compression joints which - if done properly -
seal perfectly when assembled dry. If you *must* put something on them, a
smear of Boss White round the olive is preferable to PTFE tape, but probably
acts more as a lubricant while doing it up than as a sealant.
You should also not use tape on parallel threaded joints - which are
designed to seal by means of a rubber of fibre washer between two mating
faces, rather than on the threads per se.
--
Cheers,
Roger
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Jack Fate
news:5ukg20F...@mid.individual.net...
will try to do without now. So where does "Boss White" fit into this then ?
Richard
>
Roger Mills
> "Roger Mills" <watt....@googlemail.com> wrote in message
> news:5ukg20F...@mid.individual.net...
>>
>> PTFE tape is designed for use on tapered threaded connections -
>> where the seal has to be made within the threads. [When Adam were a
>> lad, Boss White and hemp did the same job - albeit a bit less
>> tidily]. So you should certainly use tape when screwing radiator
>> valve tails into radiators. etc.
> I found that very interesting cos I have been using PTFE on
> compression. I will try to do without now. So where does "Boss White"
> fit into this then ?
> Richard
I think Boss White was just one particular make. It's the same stuff as
http://www.screwfix.com/prods/69694/Plumbing/Plumbing-Accessories/Fernox-Jointing-Compound-400g.
It's a putty-like substance, but a bit runnier than window putty. In the old
days you would seal threads by dipping your finger in Boss White, wiping
round the male thread and then winding thin strands of hemp onto it - the
final bit being similar to the use of PTFE tape. It was particularly good
(much better than PTFE tape) in cases where you needed a joint to be tight
and leak-proof at the same time as facing in a particular direction - such
as screwing an outside tap into a threaded flange, and needing the tap to be
upright.
I still use it on 'difficult' compression joints - especially if I have to
dismantle and subsequently re-assemble a joint.
Whilst on the subject of sealing pipe threads, I gather that PTFE *liquid*
such as
http://www.screwfix.com/prods/53863/Plumbing/Plumbing-Accessories/La-Co-SlicTite-Pipe-Thread-Compound-240ml
is all the rage these days - but I haven't yet tried it.
Maybe it will replace PTFE tape *and* Boss White?
John
Bob made the most significant point - cleanliness! A bit of grit can ruin a
good seal.
>
Steve
>
> Whilst on the subject of sealing pipe threads, I gather that PTFE *liquid*
> such as
> http://www.screwfix.com/prods/53863/Plumbing/Plumbing-Accessories/La-Co-SlicTite-Pipe-Thread-Compound-240ml
> is all the rage these days - but I haven't yet tried it.
I used it (actually Screwfix 'No Nonsense' brand) for the tails of the
three new radiators to TRV's and lockshields that I installed here
recently and it worked a treat.
>
> Maybe it will replace PTFE tape *and* Boss White?
It will for me ;-)
With careful application, just a smear all over the threads, it
lubricated the threads well and helped with the doing up and left me
with only a slight ring of the stuff that was easily wiped away. Far
better than trying to pick away bits of PTFE tape that would have
protruded and spoilt the appearance of the chrome TRV4's!
But, as this has been said before in this thread (sorry for pun), it or
any other sealant is not intended to make olives watertight.
Steve
Ed Sirett
On joints that make their seal using threads. However string (aka loctite
55) and resin (e.g. Liquid PTFE) do the job better, IME.
--
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
The Medway Handyman
> On Wed, 9 Jan 2008 04:27:37 -0800 (PST), 405 TD Estate wrote:
>
>> Should I use PTFE tape on threaded olive connections?
>
> No, compression joints should not require any thing other than finger
> tight plus 1/2 to 3/4 of a turn. A smallest smear of something on the
> inside of the nut to act as a lubricant is sometimes helpful.
I use PTFE on the threads of compression joints - only 1 or 2 turns - simply
as a lubricant. Agreed never on the olive.
--
Dave - The Medway Handyman
www.medwayhandyman.co.uk
01634 717930
07850 597257