Making a good compression joint.

[chelseaboylondon]

What is the best way to make a sound compression fitting joint without a leak/drip? I made 5 this weekend in my house and 2 were leaking, although I believe I may know possibly why? I have mains pressure all over so maybe this made it worse?

The pipe should go into the fitting up to the stop so fully in. And the olive then pushed down to the fitting and the nut tightened with fingers and then grips. Not overtightened though or the olive may be crushed. This is correct isn't it?

Is there any good tip to make sure it will be sound? Compound any good? ptfe/locktite on the olive/in the fitting or on the pipe end?

I believe 1 of mine was spraying possibly as the pipe wasn't fully in ? And the other a dribble as the pipe was not cut great/squarely, so I changed and got a new pipe slice with new sharp wheel and the others were all good. I am just trying to work out why this happened so in the future when I need to ake a join I will be confident.

Sorry if this is basic and sounds daft but I would just like to know where I went wrong if i may?

 

[gaspro1981]

place your fitting on to the pipe and tighten the fitting until the olive has compressed onto the pipe fully (always use copper olives) brass olives are nasty then remove the fitting and smear a suitable jointing compound around the pipe and olive and put the fitting back on tighten it all up and the jobs a good un
nice clean edges where the copper has been cut will help also

 

[Norcon]

Just tighten up until you hear an audible crunch.
Simples.

 

[chelseaboylondon]

thanks for tips. ok, copper olives from now on (how do you tell the fdifference between the 2 though)?? and when i tighten onto pipe and then undo, do i only tighten a little, then use comound and then fully tighten about 1 turn?

 

[JayJay1978]

The difference between copper and brass olives is that the brass ones have a goldie colour to them where the copper ones will be er..........copper coloured .

You're joints leaked because you didn't tighten them up enough.

Have you any idea how much damage can be done by a 15mm pipe coming out of a slack comp fitting (or any fitting)?

If you're not careful you will wake up tomorrow with you're ceilings on the floor.

The olive MUST be crushed/deformed against the pipe to make a seal, copper olives are softer and crush better. Check each fitting with toilet paper for leaks afterwoods.

 

[chelseaboylondon]

Thanks for your help, sorry i know what copper and brass ones are now, a blondde moment there!!

I have checked them all and all are good. I did do them all tight, it was just 1 of them was not cut cleanly, the wheel wouldn't cut the pipe off fully, i had to bend it and snap it off also the pipe was not fully into the stop inside the fitting

When a new fitting, ie a rad valve is used and the old olive left on, and sometimes it may dribble a bit, is this because the olive has worn? where does the water escape from, under the olive oir above it from the fitting??? any tips for this?

 

[KevC1]

Compression joints either with brass or copper olives are very simple to make. If you can't tell the difference between copper and brass I would suggest you put away your plumbing tools, and call a plumber.

Sorry to be blunt, but you'll have a lot of mess to sort out when your fittings blow off.

 

[chelseaboylondon]

sorry i know the difference, just usually use the olives that come with the fittings. i have used a few in the past.

 

[kevplumb]

finger tight then 3/4 of a turn with a spanner

 

[JayJay1978]

If a pro was swapping a rad valve he would remove the olive (olive splitter or junior hacksaw), if you must use the same nut & olive then either get some LSX or wrap a turn of PTFE round the OLIVE not the thread.

 

[bengasman]

thanks for tips. ok, copper olives from now on (how do you tell the fdifference between the 2 though)??

Copper olive can be squeezed between fingers

 

[neds]

There is never any need for additional jointing compound or PTFE tape on a compression joint, if you do need it your doing it wrong. Exception for possibly slightly deformed pipe ends but then PTFE on the washer only.

I have not had one compression joint leak on me in all my time of doing plumbing work and I have never used anything additional to seal the compression. The compression joint is such a simple design in itself. I always do use copper washers though as brass olives can be harder to get a proper 'squeeze'. Just make sure the pipe is snug in the fitting and in straight and tighten gently but enough, you will know by how much by the sound and feel back you get from the nut.

 

[nickso]

If a pro was swapping a rad valve he would remove the olive (olive splitter or junior hacksaw), if you must use the same nut & olive then either get some LSX or wrap a turn of PTFE round the OLIVE not the thread.

thats *******s.

 

[JohnD]

There is never any need for additional jointing compound or PTFE tape on a compression joint, if you do need it your doing it wrong.

as a DIYer no surprise if I do it wrong, and have not got the "feel" of a correctly tightened joint.

I got the tip on here about putting a few turns of PTFE on the olive, and have been very happy with it. It adds perhaps a minute per joint, but I haven't had any weepy joints or anything needing to be tightened or reassembled since I started doing it. For me, it is better, quicker and cleaner than using a jointing compound (I am old enough to have started out with Boss White)

 

[doitall]

Brass olives for copper, copper olives for soft copper or plastic.

Jointing compound every time and do the damn things up till the wrist hurts. they won't leak guaranteed.