Tig aluminum tungsten question

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I played a bit with tiging aluminum today and ran into a couple problems.  First problem was with the tungsten ( pure green tagged ) where it would get hot enough that the ball would grow and then dangle and I would have arc wander.  Machines set to AC no pulse at 170amps on 3/16 plates set to a T joint with the surface prepped with a stainless steel brush.  Arc length I had to within half an electrode and at times the oxide would burn off and I would get the exposed alloy and other times it would fracture the oxide but not expose it and just turn the alloy to a puddle in a bag and the electrode would get to hot and the ball would grow then dangle.  Gas is %100 Argon set to 23cf.  I I know that if the amps are to high that it will melt the tungsten but the amps on a video training project with the same size plate were set to 200amps so I'm wondering if a 3/32 tungsten is to small for 170amps?Giving up on my instructor at this point as he couldn't help me with the tungsten or that I was getting a low power constant zap from the hose through my leather.
Reply:Yes, the tungsten is too small. 1/8 tungsten is maxed out at about 160-165. By maxed out I mean that the ball will become larger in diameter than the tungsten itself.UA Local 598
Reply:Ok I'll to see if the instructor has any larger size tungsten though I doubt it and don't want to wait two weeks for Arcet to get the ordered supplies to the school.
Reply:Originally Posted by WHughesYes, the tungsten is too small. 1/8 tungsten is maxed out at about 160-165. By maxed out I mean that the ball will become larger in diameter than the tungsten itself.
Reply:Hello big65mopar, does the machine you are using have AC Balance control on it? If so, you might consider adjusting it more towards the DC- side/penetration side, depending on how it's labeled. This will somewhat reduce the heating experienced on the end of the tungsten and direct more of the energy into the basemetal/weld pool.      Can you also describe the specific equipment you are using: machine brand and model, torch type, brand, and model, water-cooled or air-cooled. Additional information in these areas might provide better and more detailed responses from everyone. Good luck and best regards, Allanaevald
Reply:I'm not the only one having this issue in my class and its not on the same machine either.
Reply:Its a syncrowave 200 and I don't know much about it as I haven't used it before today and we haven't went over the the machines hardly.  Selection ranges from dcep / ac / dcen, amps, ac, pulse, and other settings but as I said before training on the machines has been marginal.
Reply:Originally Posted by weldbead???????????????????? i know a real good aluminum tigwelder who uses 3/32 for  over 200 amps.and if the ball wasnt bigger than the tungsten , it wouldnt be a ball would it?
Reply:Miller GTAW reference, compilation of tungsten-vs-amperage info says 3/32 pure tungsten used for 100-160 amps on AC for aluminum using 65% balance electrode negative.Lists 1/8 pure tungsten for 150-210 amps on AC, still 65 % EN balance.Sine or square wave 50% balance machine (transformer not inverter machine) would  be 130 amps max AC for 3/32 pure tungsten, 100-180 amps for a 1/8 pure tungsten.If the balance is set to more EP (more cleaning action), then the tungsten gets hotter and thus the max amperage used must be less than when more EN is used.3/32 pure tungsten at 200 amps?  Maybe with some sort of pulse or a LOT of EN and not much cleaning (EP) going on.3/32 'blended' tungsten (ceriated, thoriated, lanthanated) info on AC for aluminum says 130-250 amps, same 65% balance setting.YMMV.  The best laid schemes ... Gang oft agley ...
Reply:I just went through this a month ago. I have the Lincoln PT225 which is pretty much the same as the Miller syncrowave 200. I was welding at to top end of my welder and was having the same problem. I even had the balled end drop off a couple times. After reading the hand book and checking with my LWS, I found out that 3/32 will not go that high on amps. On balanced arc, 130 amps is the very top end for  a green tungsten. Even 1/8 green has a top end of 180 amps on balance. You might be OK using 1/8 if you have your balance turned to 70% - 80% penetration but you are pushing it. Myself, I went with lanthanated ( gold ) tungsten and find they work awesome. I still had to use a 1/8 as the 3/32 had a top end of 180amps which caused me some trouble.3/32 green will not do 200 ampsMiller DVI2Lincoln Precision Tig 225Thermodynamics Cutmaster 38Everything else needed.
Reply:Sorry moonrise I posted at the same time you did.The tig hand book I have shows 3/32 Green on balanced @ 60 - 130 amp........unbalanced @ 100 - 160amps1/8 green on balanced @ 100 - 180 amps........unbalanced @ 150 - 210 amps5/32 green on balanced @ 160 - 240 amps.........unbalanced @ 160 - 240 ampsMiller DVI2Lincoln Precision Tig 225Thermodynamics Cutmaster 38Everything else needed.
Reply:I'm with the guys; Jamlit and Moonrise, as well as WHughes. For pure tungsten, it can't run as hot. A small change is to take the cleaning down a bit as posted. The other changes are to switch tungstens. I will crack 2%thor. tungsten, 3/32" at 180A in AC on alum. I will get similar results with the gold, or orange tungstens also. I use 1/8" for 180-200 amps, and since I run an inverter, I never run the pure stuff. But then again, FWIW, I ran a synchro 250 the other day, wide open with 2% thor. 5/32" and it held up really well for several hours. Really large puddle sizes, and 1/8" filler. It was HOT!!!!I'd try the changes the guys recommend here.And then, after so much work...... you have it in your hand, and you look over to your side...... and the runner has run off. Leaving you holding the prize, wondering when the runner will return.
Reply:jamlit and rojo and whughes,I always am glad when the numbers/answers I find (or post) match up with the independent numbers/answers from others.  So, to the OP, wrong tungsten and/or wrong size tungsten for the amps.  Choose again and try again.    The best laid schemes ... Gang oft agley ...
Reply:Try a different type of tungsten first. Why are you using PURE?? I have welded at 180 amps, A/C, balanced, no pulse with 3/32" ceriated tungsten and the ball never even got as big as the tungsten dia. (I grind my tung. to a point.) That is with a Lincoln PT375 with water cooled torch."SOUTHPAW" A wise person learns from another persons mistakes;A smart person learns from their own mistakes;But, a stupid person.............never learns.
Reply:Originally Posted by papabearTry a different type of tungsten first. Why are you using PURE?? I have welded at 180 amps, A/C, balanced, no pulse with 3/32" ceriated tungsten and the ball never even got as big as the tungsten dia. (I grind my tung. to a point.) That is with a Lincoln PT375 with water cooled torch.
Reply:If your using and inverter machine, get ceriated and sharpen it. Works great!Go hot, or go home!
Reply:Id recommend using ceriated or thoriated on any machine, transformer or inverter.  Ive used both extensively and would never use pure tungsten again.You mentioned having problems getting through the oxide skin, or having the puddle in a "bag."  This is probably from one of two things, either your pulling your filler material to far outside the shielding gas envelope and its getting oxidized and then transferring it back into the puddle OR, your not getting good enough coverage at the weld pool.  If your running a regular gas collet with a large cup, 23cfh might be a little low.Have we all gone mad?
Reply:Try a different type of tungsten first. Why are you using PURE??I have welded at 180 amps, A/C, balanced, no pulse with 3/32" ceriated tungsten and the ball never even got as big as the tungsten dia. (I grind my tung. to a point.)That is with a Lincoln PT375 with water cooled torch.__________________
Reply:Originally Posted by aevaldHello big65mopar, does the machine you are using have AC Balance control on it? If so, you might consider adjusting it more towards the DC- side/penetration side, depending on how it's labeled. This will somewhat reduce the heating experienced on the end of the tungsten and direct more of the energy into the basemetal/weld pool. .....................
Reply:Originally Posted by Big65mopar...................  Gas is %100 Argon set to 23cf.  ..............
Reply:****, I'm realizing that there is a problem with my instructor not teaching us things we really need to know and it is something I need to bring up to someone above him.
Reply:Originally Posted by Big65mopar . . . or that I was getting a low power constant zap from the hose through my leather.
Reply:Your instructor is not the only one that is still teaching students to use pure green.  Seems that they are mighty fine tig welders in the past, but have fallen off the cutting edge when it comes to squarewave or inverter welders.  Even Miller tells their inverter buyers NOT to use green.  I am not sure about the syncros though.  I'll have to look it up.Esab Migmaster 250Lincoln SA 200Lincoln Ranger 8Smith Oxy Fuel setupEverlast PowerPlasma 80Everlast Power iMIG 160Everlast Power iMIG 205 Everlast Power iMIG 140EEverlast PowerARC 300Everlast PowerARC 140STEverlast PowerTIG 255EXT
Reply:Originally Posted by Big65mopar****, I'm realizing that there is a problem with my instructor not teaching us things we really need to know and it is something I need to bring up to someone above him.
Reply:Ok the tig box is a miller syncro 200 set to a/c with pulser, amps set to 170 and 20 - 25cf %100 with pure tungsten for the electrode per instructor as we either use pure or thorated.As for the learning I have been figuring out most of this on my own but we don't have any books for this mod so what I have been doing is researching online and asking questions here.Also the transformer type square wave machines reach transformer "saturation" when AC welding at high current loads and will start to "miss" positive and negative cycles halves. The more out of balance they are set the sooner it happens.On my Square Wave 275 when I'm running hotter than 160 or so amps AC I'll warm the area up with propane. The 275 will lose stability fast over 200 amps AC (about 75% load). When skipping cycles there will be black specks in the puddle where the "+" cycle is missed from soot inclusions.And when missing "-" cycles more heat goes to the tungsten...Matt