AC Tig tungsten cracking

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I was doing some welds on 1/4" aluminum yesterday and I noticed the tungsten was cracking and blue-ing.  I'm using 1/8" red tungsten with a gas lens at about 20cfm.  I tried turning the gas flow up to 23 and increased my post flow timer as well but the cracking continued.  I'm using a miller 330abp and the amperage was set at 65% of the 3rd amperage range (high setting).   I tried balling the tungsten and also using pointed tungsten they both ended up cracking.I was thinking the tungsten is too thin but after looking at the amperage ratings on millerweld I'm starting to second guess moving up to 5/32" tungsten.Chuck Norris was born in a log cabin that he built with his own bare hands.
Reply:You should use Green tungstens on alum.AEAD 200LE, Lincoln precision tig 185, Millermatic 251, Spectrum 625 extreme, Victor torch , Smithy 1220LTD. and  Do all C-4 band saw ,  Always adding.
Reply:Originally Posted by rollertoasterI was doing some welds on 1/4" aluminum yesterday and ... the tungsten was cracking ... blue-ing.
Reply:The discoloration of the tungsten is a shielding gas issue like Jakeru said. My experience is with an inverter box. I personally don't like thoriated(red) tungsten on AC. The arc is unstable, the ball(more like globs) at the tip moves around and will sometimes drop or "spit" into the aluminum. I picked up some 1.5% lanthanated(gold?) and it works great. It balls slightly at the tip and produces a nice arc. The only time I've used pure(green) tungsten was on a transformer machine while in school. Wasn't too impressed with it but I'd take it over red.
Reply:Like they said,  You have 2 problems.  Discoloration is shielding gas.   Grind the tip of your tungsten like a D.  It will stay together better.  I think 1/8" is big enough.  Green IS for  your old machine, but they all work.DavidReal world weldin.  When I grow up I want to be a tig weldor.
Reply:thanks for the input.  I've tried green on thinner stuff and wasn't too impressed I may try some lanthanated and see how I like it.  It's possible that I may need a larger cup, but I really didn't have much stick out.Chuck Norris was born in a log cabin that he built with his own bare hands.
Reply:If he does not reply here, I would PM Zapster as that is the same machine he uses.. Find out his recommendations as he probably has thousands of hours of TIG welding with his 330ABPTiger Sales:  AHP Distributor    www.tigersalesco.comAHP200x; AHP 160ST; MM350P,  Spoolmatic 30A; Everlast PowerTig 185; Thermal Dynamics 60i plasma.  For Sale:  Cobra Mig 250 w/ Push-pull gun.  Lincoln Wirematic 250
Reply:I can't believe this just occurred to me, I do not have a torch cooler.  Without a cooler am I pushing the limits of 1/8" tungsten? My other big problem is the fact that I only have a 50a breaker to my shop.   I tripped it three times on Sunday, it got to the point that my helper was switching the lights off when I struck an arc to conserve power.  Unfortunately I will have to wait till spring to upgrade my service to 100a.Chuck Norris was born in a log cabin that he built with his own bare hands.
Reply:I haven't welded any aluminum as thick as you're working with but my air cooled torch gets noticeably hot in my hand when working on AC for a long time. I let mine rest for a few minutes when I notice it's hot. I also have pretty thin gloves so maybe I notice the torch is heating up sooner than you might.
Reply:If I'm not mistaken, red tungsten on high amp AC is notorious for splitting, cracking and spitting into the weld.  That being said, I think Zap uses it all the time on his 330.TA Arcmaster 300CM3XMT 304S22P12 suitcase feederX-Treme 12VSOptima pulserTA161SMaxstar 150STLHypertherm PM45OP setupStihl 020AVP, 039, 066 Magnum
Reply:I missed something in my earlier reply - you've got a 330 a/bp!  That machine has *no* pre-flow at all.  It just starts the arc right away as soon as you hit the contactor switch.You can work around this issue by altering your technique:1.  with your torch held away from the work (so no arc will happen), briefly trigger and stop the contactor switch.  This will put the gas into its "post-flow" mode (which you will use as a pre-flow with this technique.)2.  while the pre-flow is still flowing (if you wait so long that it stops, repeat step 1 again), move your torch in close to your work, and press the contactor switch again to start your arc - for real this time.  In the inert environment provided by the pre-flow purge, the arc should start smoothly, and it will be easy on your tungsten.If adjusting your post-flow time would be helpful, there is a knob behind the lower panel cover, IIRC.I really doubt what alloy or mixture of tungsten you are using will make any difference on a blueing, splitting tungsten issue.By the way, I used a 1.5% lanthanated tungsten on a 330 a/bp.  Seemed to work well to me.
Reply:Thoriated tungsten is pretty good at splitting/splintering when used on ac output.  You could try ceriated or lanthanated for an all purpose alternative, or zirconiated does well on ac.  Don't bother with pure.  Also, if you have an input power issue, try using an argon helium mix.  And increase your post flow.
Reply:Check out my thread here, I had the same problem. Now I'm using 5/32 Zirconiated when I have to weld 250-350 amps on a transformer with great results. There are pics too. Zirconiated tungstens are great for transformer based machines, they ball like green, but carry more amps. They won't split either. Downside is they are expensive.....http://weldingweb.com/vbb/showthread.php?t=62837Last edited by insterno; 12-09-2011 at 08:32 PM.Proud to support Reliable Sheet Metal Works, in Fullerton, CA.Full service sheet metal fabrication serving Orange County since 1926.http://www.reliablesheetmetal.com
Reply:Originally Posted by Drf255If I'm not mistaken, red tungsten on high amp AC is notorious for splitting, cracking and spitting into the weld.  That being said, I think Zap uses it all the time on his 330.