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walking out and getting porosity

Posted: Sat Feb 28, 2015 4:11 pm
by joshuanaaa
Hey im tig welding carbon and at the end when I go to tail out im getting porosity. This has never happened to me before and I cant figure out the cause. Help!

Re: walking out and getting porosity

Posted: Sat Feb 28, 2015 4:44 pm
by Otto Nobedder
I assume you're doing a fixed-amp weld, either lift-arc or scratch start?

Sounds like a gas coverage issue to me. After the obvious (confirming enough flow at the torch), I'd guess you're not drawing the torch back as you tail, allowing the gas stream to draw air. When tailing off a fixed-amp weld, I prefer to bring the torch to 90* to the workpiece, and slowly raise the torch in small circles until I see the puddle chill, then "snap" off, leaving a little bump like an inverted crater that my file can knock off in two swipes.

If I'm off-base in my assumptions, give us more detail.

Steve S

Re: walking out and getting porosity

Posted: Sat Feb 28, 2015 5:21 pm
by Braehill
Steve's right on track here. Most guys get porosity when they turn out the side of the weld, it creates a steep torch angle that draws air in from behind. I go back over the last 1/2" or so as I'm lifting my torch and swirling. Same thing, small volcano that can be knocked off.

Len


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Re: walking out and getting porosity

Posted: Sat Feb 28, 2015 5:52 pm
by Markus
Do you use gas lens? Switched to bigger cup?