compression fixings / rotating pipes

[sm_jamieson]

I'm fine with compression fixings, never had a leak, etc. BUT, if the final orientation of the pipe matters, I am led into increasing frustration. As you tighten the fitting, the pipe will rotate if not fixed to anything. The force is quite strong, and I tried holding the copper with mole grips, but it either squashes or chews up the pipe. I am tempted to solder a tee to the top and stick a stick in the side just to hold the thing. Some sort of clamp that goes into and around a tube to hold it without deforming it would be very useful. Typical - a connection where orientation matters, the pipes are loose fitted to hold everything at the correct angle, and the first compression fitting tighted - the pipe rotates and suddenly all the other pipes are jammed together and putting undesirable force on another connection. I have tried to guess the amount it will rotate but this is not consistent and sometimes the thing must be assembled at its final orientation. What do other people do in this situation ? Simon.

[Dave Plowman (News)]

I *know* it's not really needed, but a few turns of PTFE round the olive tends to help with this - the lower friction means the nut slips on that rather than trying to turn the pipe.

[Alan]

I don't use compression fittings it there is an alternative, and soldered fittings don't have this problem.

Alan.

[sm_jamieson]

[sm_jamieson]

Hmm. Flashback to previous discussions about PTFE on compression joints.

Simon.

[The Natural Philosopher]

The secret is to hold the FITTING with mole grips, and use that to turn the pipe back to where it should be..

[sm_jamieson]

Thats a good idea. Your trick would work if you dont care about the orientation of the fitting. But for a service valve, if you want the screw facing a certain way ... Simon.

[mike]

"sm_jamieson" wrote in news: [e-mail]:

I _did_ wonder what you were banging on about at first.

But I generally manage to get hold of the sticky outy bit well enough without destroying the valve.

I'm on that disagrees with PTFE tape too, but I find if I lightly grease all the threads, they go down well enough, and I always use minimum

*effective* force rather than mullering down.

This usually means accepting a bit of weeping when first turning on the water, getting rid of it and then a bit of extra for luck.

Works for me

mike

[Ian Stirling]

[Tony Bryer]

The previous discussions IIRC were about the need for PTFE tape to achieve watertightness. Dave's point is that it isn't needed for this but will make getting proper alignment easier.

[sm_jamieson]

seat could cause problems. Why might it be ? - something like at some point there will be a different thickness of tape where the cut end is ? Someone should do some experiments and decide on this once and for all ! Simon.

[Doctor Drivel]

Soldered is fine if you know how to do it. Compression is fine if you know how to do it. Avoid pushfit though.

[Doctor Drivel]

Compression are a nightmare. They are easy. Use a ratchet open ender.

[Doctor Drivel]

By God you nearly got it right! Not mole grips, lockable open ended smooth jaws on the fitting body and a ratchet open ender.

[Doctor Drivel]

He is half right. See my other post.

[Dave Plowman (News)]

I'd concede it *may* not do any good, but it doesn't do any harm - and for your problem, helps.

[Dave Plowman (News)]

Yup. Unless you know how to cut plastic pipe properly, that is. Like 99.9% of DIYers...

[Mark]

If you tighten the fitting with _moderate_ force just enough to start the olive compressing on the pipe then back the nut off slightly so that the fitting will just turn, align fitting and hold with grips where you need it then fully tighten nut. This works for me,I don't use PTFE or PM so im not going to add to that debate :)

-

[Dave Fawthrop]

| |If you tighten the fitting with _moderate_ force just enough to start the |olive compressing on the pipe | then back the nut off slightly so that the fitting will just turn, align |fitting and hold with grips where you need it then fully tighten nut. |This works for me,I don't use PTFE or PM so im not going to add to that |debate :)

If you need to hold a copper pipe a strap wrench will do a better job than mole grips, in that they do not damage the pipe. I now use a boa-constrictor

the strap is rubber so as not to damage things.

Also great for opening screw top jars.

[Mark]

As you replied to my post IMHO copper pipe is too soft to grip with anything effectively without risking damage. I was advising holding the fitting _not_ the pipe.

that i agree with.

-