On 11/06/2021 08:21, fred wrote:
On Thursday, June 10, 2021 at 7:08:53 PM UTC+1, John Rumm wrote:
On 10/06/2021 12:07, Dave Plowman (News) wrote:
In article , Fredxx
wrote:
On 10/06/2021 00:23, Dave Plowman (News) wrote:
In article , Fredxx
wrote:
On 09/06/2021 08:37, fred wrote:
Anyone wrap olives in ptfe ?

No, it shouts of amateur.

Oddly, it was a pro I got the tip from. Long before newsnet.


I prefer to use any other lubricant if it is necessary.
Petroleum jelly if potable.

It's not acting as a lubricant. More of a sealer.

You've contradicted this statement below?

PTFE should be confined to threads IMHO.

The threads pay no part in sealing a compression fitting.

I meant threaded fittings and not compression fittings, such as
taper threads etc.

The question was about PTFE on an olive? Using it there helps the
seal between the ends of the threaded part that the olive bears
on. It might reduce friction too - but then I always tighten
compression fittings till they groan. ;-)
One of the times that ptfe on the thread of a compression fitting
helps - you are able to work much quieter without all the squeaking
and groaning :-)

(also good for restricted spaces which need short spanners, you can
get better tightening)

So we are all agreed on this then ?

Well as ever there is some variation in opinion.

I had not heard of it until recently. We use a pressure pump and
water tank to move water around the garden. The pressure tank seal
failed so the whole caboodle had to be removed from its little house
behind the garage, which involved breaking all the various
connections. A real PITA and given that access is restricted once it
had been reinstalled I was concerned to ensure all connections were
water tight (plumbing is not my forte) so googled which was better
ptfe or Boss White plus hemp and came across a discussion about ptfe
and olives. Anyway I tried it on a few connections and all
connections were perfect when reinstalled. I think after reading this
thread I will wrap olives in ptfe in future as a belt and braces
answer. Thanks to all who responded

Personally I never wrap olives in PTFE as a routine thing, although I
have done it once or twice in extreme circumstances. I don't find it to
be necessary on a regular basis. If the parts are clean and undamaged
then the olive will work just fine on its own. Note however I do keep a
stock of new olives - so will not try to re-use ones in a questionable
condition.

Usually if a compression fitting was made successfully the first time,
just separating it and re-making it is usually easy and successful. What
can be more variable if reusing a back nut and olive on a pipe, with a
new compression body (say when changing a radiator valve) - since the
distance of the olive from the end of the pipe matters if it's too long
for the depth of the pocket on the new fitting)

Using PTFE on the threads of a compression fittings, tends to raise
screams of "bodge", "amateur", and "pointless" from those "in the know"
- but this seems to be because they believe that the tape was used to
aid sealing. They are of course correct that since the threads of a
compression fitting don't serve as a sealing surface, tape here can't
help. What they are failing to understand is that tape here is not
*intended*[1] to aid sealing directly, but to act as a lubricant, making
it easier (and quieter) to get adequate compression of the olive by the
back nut. Once could of course use a more traditional grease or pipe
fitting lubricant, although that does tend to get a bit more messy.

[1] I suppose you have to allow for the part of the Venn diagram where
the fitter mistakenly believed that tape on the threads would act as a
sealer, in which case the cry of "amateur" etc would be justified :-)

Boss white and hemp is a traditional solution but is not acceptable for
use on drinking / wholesome / potable water supplies since it can
harbour microbial growth. There is a boss green that can be used, but
hemp is still forbidden. (Although for a garden watering systems, the
rules don't apply)





--
Cheers,

John.

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