In article ,
"David Klyne" writes:
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

The olive has to cut into the pipe -- that's part of the water
tight seal. You can overdo tightening though and deform the pipe
or olives to the point where they can seal anymore.

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.

Yes (or overtightened). Really you should undo the joint to
clean out the crud rather than risking tightening crud into the
water sealing surfaces.

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