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Leak tight gas delivery system

Posted: Sat Mar 22, 2014 8:44 pm
by NYWELDERJim
Hello folks,

There have been a few thread which discussed flow regulators, gas lines, connections and the importance of a gas delivery system: from gas cylinder to torch, to be free of leaks. These discussions have made me think about the connections on my TIG welder. i was working at my son's shop today. He just bought a like-new syncrowave 180 this week (owner used it 2 or 3 times and gave up TIG, bought a MIG machine) for $400. I gave him a hand today installing the electrical circuit and settng the machine up. As part of the setup, I installed a full argon cylinder and pressurized the regulator and the gas line going into the machine. I sprayed all the regulator and gas connections with a dilute solution of soapy water and sure enough I found both ends of the gas line going from the regulator to the machine leaking, slow stream of bubbles from the fittings. Easily fixed though, they were pretty loose. I took this leak testing a it further and wanted to see how leak-tight the Dinse fitting and torch fittings were. I slid the plastic cover back off the Dinse fitting, slid the handle off the torch so I could observe the fittings on both ends of the torch hose-power cable, and removed the tungsten so I could put my thumb over the opening on the cup to seal it (and not get shocked when I depressed the power pedal). I set the regulator for 15 CFH, sprayed soapy water on the torch, all gas connections, the Dinse fitting to machine connection, put my thumb over the end of the cup and depressed the pedal. The Dinse to machine connection had a small leak and the alumina cup to white gasket had a small leak, small stream of bubles from the solution. I tightened both items up a bit, they were already tight and repeated the test. Still got a slight leak at both connections again. So I have a few questions:
1. Do you folks routinely test the end to end gas delivery system for leaks?
2. Are the two leaks I found common and acceptable?
3. How is the seal made inside the machine with the Dinse fitting? Is there a 0-ring or just a metal to metal seal?

Thanks,

Jim

Re: Leak tight gas delivery system

Posted: Sat Mar 22, 2014 11:05 pm
by AKweldshop
A lot of limes there's an o-ring or spring up in there....
I get you a pic of what I did to my SW175 to fix the dinse leak...
Pretty simple,
~John

Re: Leak tight gas delivery system

Posted: Sat Mar 22, 2014 11:54 pm
by NYWELDERJim
Thanks John. The little brass key on the Dinse fitting was bent a bit from the former owner tightening it way too much. When I first plugged in the Dinse fitting and twisted it to lock it in place, it would just turn and not lock. The little brass key was deformed, pushed forward from to much torque. I pushed the brass key back into place and it would then lock in. I did all teh leak testing after I repaired the brass key. I am going to buy a new Dinse fitting to make sure it is a reliable connection.

Jim