How to stop a valve weeping

[askman]

I know that there are other threads on this so apologies for making yet another, but I've tried a few different things and am getting to my wits end.

I have a 15mm isolation valve serving a bath tap which I've fitted and is leaking slightly more than a weep. I think that I originally tightened the fitting too tight on one side and even with a few winds of PTFE tape and some jointing compound I was getting a bit of water leaking.

I tried giving it another wind but this didnt help, tried undoing the joint and putting some fresh PTFE tape over the olive (none on the thread) and this didn't help.

Finally I managed to cut the old olive off with a hacksaw and found that the pipe was compressed by about a millimeter all the way around. Is this normal? I know that there will be a bit of deformation but having never seen a pipe with the olive removed I'm not sure.

Finally, I tried with a new olive and PTFE over it and still weeping.

For clarity, I tightened the fitting by hand and then gave it a further full wind, and when I put the PTFE tape on it was giving it a fair few winds of tape - roughly 8 or so.

Is there anything I can do short of cutting the end off the pipe and soldering in a fresh piece with a coupler?

 

[terryplumb]

You are overtightening and crushing the pipe / deforming the olive. You do not need ptfe on a comoression joint. If pipe is in good condition ,cut it lower and re fit valve with a new olive . Tighten lightly till you get to the point where the olive is gripping then another 1/4 turn should do it. Check valve cant rotate on pipe and then test with water on.