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Sealing Radiator Tails

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Colin Stamp

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Feb 14, 2012, 3:44:38 PM2/14/12
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Hi all,

A couple of weeks ago, I replaced all my radiator valves with TRVs and
new lockshields. 5 of the 9 rads needed 3/4" to 1/2" bushes and four of
those also needed tail extension peices on one end. I make that 32
joints, not including the ones with olives. I used PTFE tape on all of them.

It all went swimmingly except for three joints, which weeped very
slowly. I tightened them up - only one stopped weeping. I re-assembled
the weeping ones with loads of PTFE tape - still weeping. I re-assembled
them with PTFE tape and LS-X - still weeping. I bought new bushes,
in-case I'd cracked the old ones, and re-assebled one with PTFE tape -
STILL weeping. I'm getting a bit peeved with this...

Interestingly, all three of the weeps came from between lockshield tails
and bushes. There's only 6 joints with that combination on the whole
system. Surely that can't be a coincidence?

The lockshield valves are all PTS own-brand. I think I'll try getting
some of a different brand and use the tails off those. Does anyone have
any sure-fire ways of getting the bloody things to seal?

Cheers,

Colin.

A.Lee

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Feb 14, 2012, 5:11:20 PM2/14/12
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Colin Stamp <col.d...@stamp.plus.com> wrote:

> The lockshield valves are all PTS own-brand. I think I'll try getting
> some of a different brand and use the tails off those. Does anyone have
> any sure-fire ways of getting the bloody things to seal?

More tape, more decent sealant - not LSX, use a 'boss white' style
sealant, and do it up really tight.

--
To reply by e-mail, change the ' + ' to 'plus'.

Andrew Gabriel

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Feb 14, 2012, 5:12:53 PM2/14/12
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In article <BaWdnaawdb4qWqfS...@brightview.co.uk>,
I usually start with 10 turns of PTFE on radiator tails.
If the tail hasn't got stiff to turn before it bottoms out,
disassemble, strip and discard the PTFE, and repeat with 15
turns. I don't think I've ever needed more than that.

Also, make sure you put the PTFE on the right way around,
so that screwing it into the radiator is effectively pulling
it tighter, not undoing it.
http://www.youtube.com/watch?v=65i2vGWi3AE

--
Andrew Gabriel
[email address is not usable -- followup in the newsgroup]

Roger Mills

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Feb 14, 2012, 5:53:40 PM2/14/12
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Use gas-grade PTFE tape - it's much tougher than the usual stuff.
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Cheers,
Roger
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Colin Stamp

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Feb 15, 2012, 3:42:04 PM2/15/12
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On 14/02/12 20:44, Colin Stamp wrote:

Thanks to all who replied. I went out and got a pair of new valves at
lunchtime, came home this-evening to fit them only to find the pump had
packed up. Now I've fixed that, I'm all plumbed out for tonight. The
tails will have to wait until tomorrow.

The pump was particularly annoying since I knew it was on the way out
and I have a Grundfos Alpha 2 on back-order. Now I've ended up fitting
the cheapest one Toolstation sell and I can't decide whether to cancel
the Grundfos order or not...

Cheers,

Colin.

Colin Stamp

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Feb 16, 2012, 4:01:12 PM2/16/12
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Well, both the new tails sealed nicely with and 10 turns of PTFE (which
is less than I tried on the original tails at one point) and no sealant.
I guess it was something strange about those particular PTS tails and
the brass bushes. Weird!

Cheers,

Colin.

fred

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Feb 16, 2012, 6:16:05 PM2/16/12
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In article <7oOdnXZwjt0E86DS...@brightview.co.uk>, Colin
Stamp <col.d...@stamp.plus.com> writes
Your experience was similar to mine a few years back (a few weeping
joints out of 12 or so rads) so I switched to one of the liquid ptfe
type sealants and I haven't used ptfe tape since for water work, liquid
has sealed all joints first time since.

Others here have reported ptfe tape being ripped by burrs on internal
rad threads and have had some success by cleaning up those threads with
a tap but life is too short and I'll stick to liquid sealants.
--
fred
it's a ba-na-na . . . .

Andy Wade

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Feb 16, 2012, 7:39:56 PM2/16/12
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On 16/02/2012 23:16, fred wrote:

> Others here have reported ptfe tape being ripped by burrs on internal
> rad threads and have had some success by cleaning up those threads with
> a tap but life is too short and I'll stick to liquid sealants.

Yes, where the threads are a bit rough and the fit is loose I tend to
use good old fashioned paste (boss white, etc.) and hemp. I've never
has a joint leak, done that way.

--
Andy

PeterC

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Feb 17, 2012, 3:42:42 AM2/17/12
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Same here - had a brand-new Stelrad and couldn't seal a thread with any
amount of any sort of tape; bit of Hawk White and job done. I often use it
in small amounts even if not needed as it 'lubricates' the whole joint so
that all of the 'feel' is in tightening rather than friction.
--
Peter.
The gods will stay away
whilst religions hold sway

Colin Stamp

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Feb 17, 2012, 12:03:51 PM2/17/12
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Yep. My faith in PTFE tape has taken a bit of a battering during this
last job. I've never liked these threaded joints. I reckon they can
sense the presence of dodgy DIY plumbers.

Cheers,

Colin.
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