Joining copper pipe and the Wiki

[dennis]

Brass or copper olives certainly aren't going to dig into stainless pipe or chromed pipe and compression fittings still work.

[Andrew Gabriel]

If you put a sealant on a compression fitting, it's no longer being used as a compression fitting in accordance with the relevant British Standard, and that makes it an illegal part for gas installation as all parts have to conform to relevant BS (or BS EN).

Even using a lubricant, you can't really prove you didn't get it onto the sealing surfaces, and thus produce a non-conforming coupling.

There are gas fittings (and water fittings) which *require* the use of a sealant, such as BSP taper threads. If you are using PTFE tape, note that for gas, the thicker tape (comes on a yellow spool) must be used, and in a particular way which gives precisely 2 layers.

[Capitol]

Air con joints use ptfe paste sealing compound. Personally I find it not very good.

[John Rumm]

There was not, but I notice that Nige had a bash at starting one last night. I took some photos and stuck them in it today.

It varies a bit with different fittings I find - half to 3/4 turn from hand tight usually.

Lubricating the threads also makes tightening them easier and more consistent I find. (either pipe jointing compound/lube or PTFE)

[John Rumm]

I have a pair of those, and they are good, however its a shame they are not 12 point rather than 6. Quite often its difficult to get them into location and have enough space to rotate them to the next flat.

[John Rumm]

Can't say I have really noticed any difference.

[John Rumm]

I find you do need a little more torque on the nuts on chromed pipe for that reason though.

[John Rumm]

Small nozzle blowtorch (Bernzomatic quickfire II) and a decent heat mat is my normal solution in those situations.

[John Rumm]

[sm_jamieson]

I tighten them until the spanner judders and a kind of clicking sound ensues. If I lubricated the thread or the olive I suspect the juddering would not happen and I would have lost my cue. Simon.

[Tim Watts]

Cool :)

What's your favorite lube (oo-err missus)?

[Tim Watts]

Cheers John - I'll look at that.

My old blowtorch is a bit knackered anyway...

[Adam Funk]

That looks handy. Are the compression rings always the same size on the outside for the same size pipe? (I know the threads aren't always the same.)

That looks handy too. Thanks for the tips.

[Adam Funk]

Fair enough, but now I want to know why the sealant is allowed for water but not gas with the same kind of pipe?

[Tim Watts]

Because water doesn't blow the side out of tower blocks ;)

[Adam Funk]

In other words, using the sealant on such joints water pipes in water pipes is also A Bad Thing, but just not dangerous enough to be prohibited?

[Adam Funk]

Oh, what I was really getting at was this: I was wondering if the properties of gas & water differed in some way that gas might react with the sealant.

[Capitol]

Gas will leak through a smaller hole than water will. So a joint can be water tight, but not gas tight.

[Adam Funk]

That makes sense. I wondered if there was anything chemical going on too.

[John Rumm]

Yup they are very good - especially on chromed stuff where you don't want any slip to leave scratches etc. Also good for being the non moving spanner holding the fitting, since they can lock on leaving you only worrying about keeping one spanner on the nut!