Copper airline leaks

[Will67]

I just completed installing an airline distribution system in my garage. All fittings were sweated together with silver solder. I used a three unions, and I can not get these to seal. I have not used anything on ten copper mateing surface and wonder if this would help.

Any useful suggestions?

Thanks in advance

 

[plumbstupid]

You should not need to use anything. Sometimes it helps to use some pipe dope an the mating surfaces of the union and tighten the piss out of it.

 

[jatherton1]

Try polishing with steel wool or fine sandpaper and applying a little flux before applying the solder. If the surfaces are clean use non acid flux.

 

[kwb]

Dumb question but if you sweat together the entire system why would you put unions in?

 

[Gary S]

In all the soldering I've done over the years, I've never used silver solder. Silver solder needs much higher temps to solder correctly, and I've never seen it used for plumbing. I've used it only on high power transmission lines used in TV and radio broadcasting where high temps will cause regular solder to fail.

 

[bgott]

He isn't having problems with the silver solder, he's having problems with the unions. Since you already know how to solder, this one is easy. Desolder and remove the unions and solder in some splices. Problem solved. If you ever have to break the piping, get out your torches.

 

[bgott]

In all the soldering I've done over the years, I've never used silver solder. Silver solder needs much higher temps to solder correctly, and I've never seen it used for plumbing. I've used it only on high power transmission lines used in TV and radio broadcasting where high temps will cause regular solder to fail.

It's also used for A/C system soldering.

 

[rickairmedic]

It's also used for A/C system soldering.

Yep I go through it like Jolly ranchers .

To the OP I am wondering what kind of unions you used . The unions I use on copper water lines have rubber seals that go between them and also have plastic parts that have to be kept cool while soldering the unions in .

Rick

 

[djjsr]

I am wondering what kind of unions you used . The unions I use on copper water lines have rubber seals that go between them and also have plastic parts that have to be kept cool while soldering the unions in .

Those unions with the plastic isolators and rubber seals are dielectric unions to be used with dissimilar metals. Regular bronze unions used for copper don't have the plastic rings or rubber seals. The mating surfaces are machined.

 

[Will67]

The unions are leaking at the copper to copper matting surface. The sweated joints are fine. I have made sure the matting surface was free of scratches nd I have tightened them as much as I dare. I suppose if I have to, I will take em out...but with them servicing the air compressor will be so much easier in future.

Nothing is ever easy I guess?

 

[djjsr]

Use a rubber hose whip and a quick disconnect fitting to connect your compressor to your rigid lines.

 

[Frank The Plumber]

Try using some fine pipe dope or a touch of graphite on the mating surfaces as was suggested. Put a bit of lube on the running threads that draw them together to overcome the friction. A lot of times these things get tossed about and end up slightly out of round. They should bond up decent and seal at the sealing surfaces if you over come the friction.

 

[gmwelder86]

Plumber/pipe fitter by trade here so I know what your going through. I would just put a little pipe dope on the mating surface, I know technically you shouldnt have to but hey this usually works. Did you silversolder the unions on or use soft solder?

 

[ZRX61]

Use a rubber hose whip and a quick disconnect fitting to connect your compressor to your rigid lines.

What he said.

 

[rlitman]

Use a rubber hose whip and a quick disconnect fitting to connect your compressor to your rigid lines.

That QD is a bad idea. It's a bad place to add unnecessary flow restriction.

 

[Zeke]

Try a little lapping compound on the mating surfaces. Assemble with dope but don't charge the system right away. Give the dope time to set up. If it's cold there, use gentle heat from a hair dryer. No more than 100* for a few minutes. Let cool and cure.

Lots of guys blow out their pipe compound before it's ready.

 

[PT Doc]

Why not use the Shark Bite connectors? They are reusable and come in various configurations. Inline straight connectors come in various lengths and should work for your application.

 

[sdowney717]

try the teflon pipe dope rectoseal

 

[Ron Lombardo]

Gray Pipe Dope ....and I know its too late now to ask .. but were the two ahlves of the union seperated ... because msot times they are ground as a pair ... but gray dope on the threads will enable you to tighten them.

 

[ddawg16]

I put a skim coat of RTV on the mating surface of the union.

 

[MustangRick]

I used a braided pressure hose from McMaster Carr to connect my compressor to my air line. It cushions the vibrations from affecting the lines. I believe they have ends that turn like a garden hose to allow your maintenance. Otherwise you can just screw a 90 degree fitting onto it and solder it onto your pipe. If you ever need to take it off, the 90 degree arrangement will allow you the flexability to desolder it and reconnect easier.

 

[MustangRick]

I forgot to add that I had blackpipe with unions in my first endeavor. I went copper this time because unions ****, and I only have a 2 car garage so the price of copper wasn't that big of a deal. They seem to seal when you originally install them but the first time you take them apart they leak, but that was black pipe that can rust.

 

[Ron Lombardo]

Standard practice is anytime you attach a motor to a piping system you should have a vibration flex hose in line ... it prevents a multitude of problems ranging from vibration noise, to loosening hangers, to loosening joints, to hammering with solenoid valves ?