TIG delima

admin

I hooked up my tig torch to my DC 250 idealarc I scratched an arc on a piece of copper tubing and then went off on steel. My tungsten keeps balling op and burning back. Using argon and DC reverse. Whats wrong?
Reply:Your using the wrong polarity.You want to use DC- (straight) for scratch start tig-ing steel. DC+ (reverse) puts 70% of the heat in the electrode (tungsten) and 30% heat in the work. DC- (straight) puts 70% of the heat in the work and 30% of the heat in the electrode (tungsten). That's why your melting or balling up your tungsten.What tungsten are you using?Last edited by snoeproe; 09-03-2009 at 10:21 PM.JasonLincoln Idealarc 250 stick/tigThermal Dynamics Cutmaster 52Miller Bobcat 250Torchmate CNC tableThermal Arc Hefty 2Ironworkers Local 720
Reply:The red one. I think its 2% thoriated, right? Thanks, I will change it tomorrow. Skeeters too bad tonight. I switched it once but didnt get but much more than a spark. I will turn her up a bit and try again. Doing this on a shoestring budget. I want to see if I can get good enough to build me a stainless steel maple syrup evaporator.I am a stick welder by trade and I work in a shop that has all wirefeed welders, quite humiliating. Ha. Thanks Harold
Reply:Yup, the red 2% thoriated is the tungsten you want to use. My idealarc 250 welds SS real nice with scratch start tig.JasonLincoln Idealarc 250 stick/tigThermal Dynamics Cutmaster 52Miller Bobcat 250Torchmate CNC tableThermal Arc Hefty 2Ironworkers Local 720
Reply:You need DC straight polarity (DCEN, torch negative), not reverse.MM350P/Python/Q300MM175/Q300DialarcHFHTP MIG200PowCon300SMHypertherm380ThermalArc185Purox oaF350CrewCab4x4LoadNGo utilitybedBobcat250XMT304/Optima/SpoolmaticSuitcase12RC/Q300Suitcase8RC/Q400Passport/Q300Smith op
Reply:Thanks guys, I found something else too. I switched to straight or what I thought was straight. But the paint is worn on my welder and I just got it so I was going to AC. Trust me it dont work either. Ha. I do have a question. Is my tungsten supposed to turn red? I am using 1/16 thoriated but maybe I need to go bigger. Also does anybody ever clean the grove out in the collet? And if so what do you use for that. Harold
Reply:I prefer to use 3/32 tungsten and collet and mostly 3/32 filler rod and on occasion 1/8 filler rod. For most tig jobs I do, I rarely go over 60 amps. I don't recall seeing my tungsten get red. Be sure your using somewhere around 20cfh argon flow. Does your torch have an on/off gas control on it?On the Idealarc 250 polarity switch (mine anyway), down is AC, middle is DC+ and up is DC-.Last edited by snoeproe; 09-04-2009 at 11:47 PM.JasonLincoln Idealarc 250 stick/tigThermal Dynamics Cutmaster 52Miller Bobcat 250Torchmate CNC tableThermal Arc Hefty 2Ironworkers Local 720
Reply:I use 3/32" tungsten most of the time. It has a very broad operating range. It's completely normal for the Tu to glow when welding. I use a shorter stickout and only see the tip and arc most of the time.I use a 7 or 8 cup. (7/16" & 8/16" ID) I don't weld in confined spaces and the larger cup is more forgiving with stickout. Stickout should be 1/2 of cup diameter or less.TIG likes a short arc. Try for 1/8" or less. Don't try to weld over mill scale, porosity will result. Grind or flap disk, a powered wire brush isn't aggressive enough.Notice the color of your arc with a freshly ground Tu, it will usually be a pale yellow. If it turns green, stop and regrind. You've contaminated the Tu, porosity will usually follow.Edit: I run my fingernail thru the collet split once in a while, but it's mostly to loosen the collet, so the Tu will slide in and out easily for setting my stickout. Thanks for telling us about the AC mixup. Easy to do without good stenciling. Last edited by Craig in Denver; 09-05-2009 at 01:15 AM.9-11-2001......We Will Never ForgetRetired desk jockey. Hobby weldor with a little training. Craftsman O/A---Flat, Vert, Ovhd, Horz. Miller Syncrowave 250