Copper pipe compression fittings - rule of thumb?

[Tim S]

Just out of curiosity - I've come across various rules of thumb for copper
compression joints eg:

finger tight then 1-1.5 turns,

or spanner until olive just grips then some random small amount more.

I only ask, because I used a cap off 22mm brass fitting today, which needed
no more than 3/4 turn after finger tight to compress the olive into the
pipe. It seemed to have a pretty decent hold after 1/2 turn.

Do they really vary this much? I seem to remember getting more turn on
previous fittings I've used.

I disassembled it to check, being convinced it wasn't enough, but no, just
right - olive nicely biting in without excessive deformation.

I even used a tiny smear of compound on the outside of the olive as
lubricant.

Cheers

Tim

[Dave Plowman (News)]

In article <4a1ee0c8$0$510$5a6a...@news.aaisp.net.uk>,

Tighten then dry until they groan. Works for me. ;-)

> Tim

--
*A fool and his money are soon partying *

Dave Plowman da...@davenoise.co.uk London SW
To e-mail, change noise into sound.

[David in Normandy]

Tim S wrote:
> Just out of curiosity - I've come across various rules of thumb for copper
> compression joints eg:
>
> finger tight then 1-1.5 turns,
>
> or spanner until olive just grips then some random small amount more.
>

Previously I'd only ever used compression joints for the small amount of
plumbing I'd done. That always baffled me too. Too slack and the joint
leaks, too tight and the olive distorts too much... and it leaks. Nudge
the joint... and it leaks.

Over the last few weeks I've done a fair amount of plumbing and learned
how to use solder end joints. I'll never look at a compression fitting
again - hideous things. Not a single one of my (80+) soldered joints
leaked. They are also much more sturdy - not to mention vastly cheaper
than compression fittings.

--
David in Normandy.

[Donwill]

Dave Plowman (News) wrote:
> In article <4a1ee0c8$0$510$5a6a...@news.aaisp.net.uk>,
> Tim S <t...@dionic.net> wrote:
>> Just out of curiosity - I've come across various rules of thumb for
>> copper compression joints eg:
>
>> finger tight then 1-1.5 turns,
>
>> or spanner until olive just grips then some random small amount more.
>
>> I only ask, because I used a cap off 22mm brass fitting today, which
>> needed no more than 3/4 turn after finger tight to compress the olive
>> into the pipe. It seemed to have a pretty decent hold after 1/2 turn.
>
>> Do they really vary this much? I seem to remember getting more turn on
>> previous fittings I've used.
>
>> I disassembled it to check, being convinced it wasn't enough, but no,
>> just right - olive nicely biting in without excessive deformation.
>
>> I even used a tiny smear of compound on the outside of the olive as
>> lubricant.
>
> Tighten then dry until they groan. Works for me. ;-)
>
>
>
>> Tim
>

I always substitute a copper olive instead of the usual brass one
supplied, in the belief that the copper one is more easily squeesed on
to the pipe.

[Tim S]

David in Normandy coughed up some electrons that declared:

I agree - most of mine won't be compression.

This one was capping off a gas pipe close to the meter - thus I can't solder
without capping the meter itself, and whilst I'm happy with copper gas
work, I'm not very happy pratting about with meter connections, though I
noticed mine appeared to have a 22mm compression adaptor on, so I might
revise that.

Yes, it did pass a full gas tightness test :)

[Tim S]

Donwill coughed up some electrons that declared:

>>
> I always substitute a copper olive instead of the usual brass one
> supplied, in the belief that the copper one is more easily squeesed on
> to the pipe.

That's a good point...

I've never had much trouble getting olived to work - I was just curious
about rules of thumb for speed purposes, and why none of the rules of thumb
seem to apply to <random> joint I did yesterday. I thought the screw pitch
was unified, which is about the only thing I can see that would make a
difference...

Cheers

Tim