"Dave Plowman (News)" wrote in message
...
In article ,
David Klyne wrote:
I have recently extended some pipework using compression fittings. It
had been suggested to me that I should not over tighten the fitting as
the olive could cut into the pipe. Now I have notice on a couple of the
fittings that whilst they appear water tight there seems to be a powery
deposit forming round where the pipe goes into the fitting. It suggests
to me that I have not tightened them correctly but would appreciate any
feedback.

A correctly tightened compression fitting should have the ring compressed
so that it can't be removed from the pipe easily. And you'd have to use a
deal of force to overtighten one. So not easily done with the correct
spanners. You'd have to be using extra long types.

IMHO most give problems because of damage to the pipe in some way -
linear scratches being a favourite cause by the pipe being pushed through
some small hole etc. That's the beauty of a soldered joint - if the pipe
and fitting are cleaned properly solder will fill any such small
irregularities.

If the pipe and fitting have been cleaned properly (wire wool and a wipe, no
scratches), a compression joint will be just as fine! You can get away
without cleaning a soldered joint as well (with powerful flux), true, but
they're the same if properly cleaned.

I once heard that plumbers "never fully tightened compresssion joints
because, if there's a leak they still have something to tighten".

It is also true that , for a properly tightened compression joint (finger
tight then 1/4-1/2 a turn), you won't get the olive off.

Don't forget to clean the olive as well as the pipe/fitting.


--
Bob Mannix
(anti-spam is as easy as 1-2-3 - not)