Tungsten burning up before the puddle gets started

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It is not my first buffet line with TIG and I have taken and passed various tube tests(i.e the Boilermakers Common Arc test) without issue. I am having a huge problem with my 1/8 tungstens burning up. I am using 1/8 2% Thoriated, 100% Ar, about 19 on the flow, 125 on the dial, DCEP, and a 3/8 cup(no.6 maybe?). I can't even get a puddle going without it killing the tungsten. This all seems to be within the parameters of the wire. Any thoughts?Troubleshooting I played with the Ar. flow. Went to 15CFM up to 22Cfm. I also went down to 95 on the dial. 'Mike
Reply:You need to be on DCEN.  Only time DCEP is used in tig is for thin stuff at very low amperage with larger tungsten.Have we all gone mad?
Reply:Yep, Snowboarder is right, I tried welding some aluminum with DC, both EN and EP and on EP, my tungsten went 'poof' and disappeared as soon as I put my foot down.MM350P/Python/Q300MM175/Q300DialarcHFHTP MIG200PowCon300SMHypertherm380ThermalArc185Purox oaF350CrewCab4x4LoadNGo utilitybedBobcat250XMT304/Optima/SpoolmaticSuitcase12RC/Q300Suitcase8RC/Q400Passport/Q300Smith op
Reply:1/8 tungsten is rated for 250-400A DCEN, but only 25-40A DCEP.Even at 95, its going to go poof on DCEP.have a look at:http://www.carmenelectrode.com/wp-co...g-currents.jpgIts not an exact science, and different types of tungsten handle DCEP better (thoriated is a poor choice), but that should get you in the ballpark.Are you trying to weld Aluminum DCEP (I hope not)?At 125A DCEP, you'd need a monsterous tungsten (possibly 1/4"), and should be using zirconated or lanthanated.  That's why Aluminum is best welded with unbalanced AC (where I can use a 3/32" zirconated tungsten happily).If you're trying to weld steel, you want DCEN, and should probably be using 1/16" tungsten up to around 150A.  1/8" will give you a hard time starting and not as nice an arc.
Reply:The only time I use DCEP is to ball the tungsten for aluminum welding. Beside that; A/C for aluminum & magnesium, DCEN for steel, brass, & copper.
Reply:Thanks guys..might I add DUH to me. I was in a rush trying to get stuff done and neglected to change my polarity. I am welding mild steel. I have 3/32 filler and 1/8 red tungsten. Most of it is multi pass stuff on 3/8 or better although some of it is 1/4. Thanks guys. I will make the adjustment tomorow and see if that makes a difference.'Mike
Reply:DC neg and you have no problem.....I'd rather be hunting........USE ENOUGH HEAT.......Drifting around Aussie welding more pipe up, for something different.....wanting to get home.
Reply:3/8 -1/4" steel; Set your machine at 250 amps DCEN (no pulse) , 1/8" tungsten is perfect, 3/32" ER70-S2 filler is prime for mild steel. You should be good to go. Hope all worked out for you on Friday.Last edited by papabear; 02-14-2009 at 11:24 PM.