I am doing a job for someone as a favour.

Chrome pipe dropped from a service void down to taps.

Where I have used brass compressions on the chrome pipe in the service void to connect to the copper pipework, everything is fine.

Where I have used chrome compressions on the chrome pipe down in the room I am finding they are all weeping, some worse than others!  Never had issues with compressions before really, well nothing a quick nip doesn't sort.

I have used some PTFE on some which has sorted them, but others are proving to be a pig.

When PTFE'ing a compression (never had to do this!), can I put some PTFE between the olive and the fitting, as the water seems to be coming out from underneath the olive IMO, and not through the thread.

Whats the best way to try to solve this?  Just plenty of PTFE?

I suspect I have some crappy commpression fittings, although they did come from a proper merchants.....

Ta!

No need for PTFE on a compression fitting "thread" - theres no water going through there  

Chrome plating can crack when using compression fittings, usually wrapping PTFE round the olive will solve the problem, if not, you may need to remove the olive, scratch away the plating to reveal the copper then remake the joint.  I always use a dab of boss white round the olive when I do a compression joint


PS - are they brass olives?

You can no longer rely upon a compression fitting as supplied - being gas or watertight from new.

The quality of the olives has now reached a point where it's shitee.
The quality of metal  - brass or copper - used in the manufacture of olives is hopeless. Copper is always to be preferred over brass (because it's softer) but even then, you'll need PTFE or LSX paste to do a proper job.

I've moved over to HEP or Speedfit plastic fittings now - they are similarly expensive and bulky when compared to a soldered joint, but are much better than all-metal compressions when it comes to sealing first-time round.

TT

"If you use jointing compound on the olives they don't leak. end off."

...and a bloody sight easier than trying to wrap PTFE when the joint's close against a wall! Must start using that stuff then, when I come on compression fittings.

Like TT, I prefer the speedfit fittings. Used one when replacing the stop cock on that mate's plumbing to fix the new section (stop cock, knackered anyway, had to be raised to clear the base of the base unit) of pipe because we couldn't isolate the supply from the two neighbouring cottages because no one was in to turn off their stop cocks to prevent draining their systems! Made up the new section and just pushed it on immediately the pipe was cut, had about a cupful of water on the floor.

no.. the teeth of the fittings can not bite into the chrome plating.........