Leaking compression fitting help

bob22

Installed water filter using 1/4" od soft copper tubing x 3/8" NPT fitting.
I'm getting about 1 drop every minute that seems to be oozing between the compression nut and the tubing (a Watts fitting from big box store). First tried to do them without dope on fitting threads and had a leak. Disassembled and applied some dope and still a leak.
I've tightened them about as much as possible. Any thoughts as to how to avoid this tomorrow when I cut off some tubing and start again?
Originally, I assembled hand tight and then 1 revolution on nut with wrench and then tightened until I thought it stopped (but it didn't).

kenmac

That's why I don't like compression fittings. You may have to really crank down on it to stop the drip

bob22

Ken,
I'm maybe a 1/4 turn from no more tightening; I'm afraid of splitting the nut, is that possible?

kenmac

I 've never split 1,but I've had to tighten some of them very tight to stop a drip & use some pipe dope. Did you make sure the pipe all the way in( home) when you 1 st tightened to crush the ferrule ?

bob22

Yes, it was in the fitting as far as it would go. There really is no other sensible way to do this without compression fittings as the tubing has to go into 3/8" NPT female ports on the filter. Do they make shark bites for 1/4 od (if I get desperate)?

kenmac

Don't know about shark bite that small. You can always flare the copper and use flare fittings

bob22

I've never flared copper; are flared fittings generally less leaky? I guess all joints are generally not leaky if done right though.

bob22

Redid two ends of the tubing. Only one now leaks; a very small drip. Talk about frustration.
I'm going to plan B next weekend. Premade pex fitting from Westinghouse:
http://www.homedepot.com/h_d1/N-5yc1...atalogId=10053
Anyone use it?

VIPlumber

No, I've never tried them. I always use the stainless steel braided ones and buy them at the local plumbing supply house.

Docwhitley

What I usually find is something stupid... so I would give 1 more try with a new Ferrule... Cut the tube put the nut then the ferule on I always push it up the pipe a little so I can make sure the tube is all the way seated... then move nut and ferrule down and tighten it till the Pipe cries.

Interesting a Ferule is an instrument used to torture and punish children

A Ferrule is something used to torture adults!

bob22

Doc,
I'm using copper so no ferrule is used.
VIP,
I used copper tubing so I wouldn't have to replace the braided over time since they don't last forever.
I don't know if it is the Watts' nuts and sleeves or the tubing or my technique (last one, I oiled the sleeve and fitting that supposedly helps), made sure it was seated all the way, hand tightened and then tightened 1/3 turn with wrench. Turned on the water and continued small tightening increments, waited for dripping, tightened, and soon I had no more thread left to tighten and still had a slight weeping. Urge to kill.

Docwhitley

Ok... This is going to sound stupid.. Make sure the built in Ferule is there. you can look at the nut and it looks like a sleeve going through the nut. I have gotten them where they were not there

bob22

Doc,
Since this is copper, the ferrule is not used. The compression ring is there and it is leaking between the ring and the tubing a few molecules at a time I guess.

Docwhitley

Ok as long as the sleeve if there. I have had them missing.

Only other thing I can think of is to take your time cutting the pipe to make sure your cutters are not nicking the copper or making any grooves. Then make sure it is completely seated in the fitting. I feel for you... I do this for a living and it took me 6 tries about 2 weeks ago in my house.

epson

Make sure the copper tubing is not bent, dented or flattened where the connection will fit or you will have a leak and cut all tubing with a tubing cutter...