Tips on copper compression fitting?

speedball1 · Jan 7, 2005, 10:00 AM

Quote:

Originally Posted by harleyds

My problem is whenever I work with coppoer compression fittings, I never seem to get a good seal and something always leaks. Are there any tips on how to do it right? Should I use a hack saw verse my Reciprocating Saw to cut the tube? (SLow vs Fast).

I know the cut has to be straight, then slide in the screw part over the tube and then the "flange". Then connect it to the male connect and then tighten. I also always use teflon tape on the male side.
How tight should it be?

Let's get together on terms. Screw part=compression nut. Flange= ferral, male side = Compression fitting
Purchase a set of cheap tubing cutters from the hardware store and use them. DO NOT USE teflon tape or pipe joint compound on any compression fitting. When tightening put a wrench on the compression fitting for backing while tightening the compression nut. Crank down hard when tightening. Good luck, Tom

labman · Jan 7, 2005, 10:04 AM

I never have much luck with them either. Be interesting to see Tom's answer. I think the regular tubing cutters would do better than any saw. Try not to nick the tubing or any of the parts. You shouldn't need the Teflon tape. The threads are not where it seals, but between the ferrule, ring, and the tubing and seat. Out of desperation, I have tried tape over them. My usually technique it to tighten it up until I think I am nearing stripping the threads. Then when it leaks, tighten it up some more. If that doesn't work, I fool around with the tape, and once I put an O-ring in. Maybe my problem is over tightening it to start with. Maybe try snugging it up and check for leaks. If so, tighten it up a little at a time. I know pipe fittings can be over tightened, stretched, and then always will leak.

Frankly automotive and industrial applications are getting away from metal to metal seals. The big problem is entirely too many new products that don't work with each other.

tommytman · Jan 7, 2005, 07:42 PM

Compression fittings like the one you talk about use a metal to metal seal. The nut compresses the ferrule into the pipe. Therefore, these connections don't need pipe dope/teflon tape. The tubing must be concentric and without marring or it won't work well...cutting with a saw will probably deform the tubing making for a crappy seal....especially with a recip saw.

harleyds · Jan 10, 2005, 09:33 AM

I used a pipe cutter as suggested and made sure it made a perfect cut. Other attempts resulted in a spiral pattern!

After I made sure the cut was perfectly even and round, I inserted the nut and then the "flange" as the bag from HomeDepot called it. Then I tightened it up and luckily had no leaks on either end.

Thanks all!

tommytman · Jan 10, 2005, 07:09 PM

Great!

About the "spiral cuts"....did your pipe cutter make those by spinning around the pipe but not staying in the same groove? If so return it and get a different pipe cutter...that "spiral cutting" is no good. I recently got a pipe cutter from Home Depot that did that...it was crap.

harleyds · Jan 11, 2005, 11:31 AM

Quote:

Originally Posted by tommytman

Great!

About the "spiral cuts"....did your pipe cutter make those by spinning around the pipe but not staying in the same groove? If so return it and get a different pipe cutter...that "spiral cutting" is no good. I recently got a pipe cutter from Home Depot that did that...it was crap.

It came in a set. One was a larger on, I guess it was standard size. This one is fine. It was a smaller one, fits in the palm of your hand that was making the spiral cuts. I bought these about 4 years ago. I think this was the first time I tried using the smaller one. I'm not sure they would take it back now.

David

Bev Sabre · Jan 17, 2005, 04:32 PM

Thanks guys - I was having trouble with installing a water line for an icemaker. (Leaks) After practicing with a pipe cutter (nothing ever comes with directions - I found how to use one on the net) I followed Tom's advice and it worked great!

medinapool · Jan 9, 2011, 07:36 PM

Everything I have read on compression fittings is you should tighten until small resistance then a half turn. That way you haven't over tightened. Turn on water slowly and watch. If you have a leak turn 1/4 more and usually you are good to go.

massplumber2008 · Jan 10, 2011, 04:21 AM

Hi Medina...

You are probably talking about the compression fittings attached to the newer BRAIDED supply hoses...not regular compression fittings.

The braided hoses do indeed require the hand-tight plus 1/4 turn but the reality is that you need a full turn on two to "set them and forget them"...

Full on compression fittings require us to go hand-tight plus 2-3 or more turns...really a feel thing here.

Have a good day!

Mark

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