starting a tig bead

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a have bben practicing tig on some aluminum and steel. I have done quite a bit of oxy acet on steel and aluminum. When i start a bead using 3/32 tungsten on !/8 alum the initial arc seems to make a pretty good snap then after the puddle forms it is ok. With 1/16 tungsten on 1/16 alum I am not seeing this problem, if it is a problem. I have the amps at 125, balanced weld. Machine is a synch 250 with pure argon set at 20 cfh. It seems the arc should start a little less violent.Any suggestions? They are just coupons so nothing structural
Reply:since it doesnt happen with the 1/16 tung, look at the 3/32 collet, maybe its nicked and the arc is erratic...?
Reply:how can you tell nickel
Reply:actually thinking about it ive tried two different collets
Reply:Make sure the workpiece has a good ground.  If it's just sitting on the bench . . . especially aluminum . . . the initial surge may be because it's welding itself to the bench.  Look for an arc burn on the bottom of your work.Dynasty 300DXSmith He/Ar gas mixerMM350PHobart Handler 120Smith LW7, MW5, AW1A
Reply:will do
Reply:Benchracer,"Balanced" on a Sync 250 is a 3 on the balance knob.When welding aluminum with that machine, I prefer to set my balance control between 7 and 8.You don't really need all the cleaning a setting of 3 will give.  A higher setting puts more heat into the workpiece and less heat into the tungsten.You didn't mention what type tungsten you were using.  Many still like pure (green) on the Syncs (balled tip).  I prefer the 2% Lanthanated, sharpened to a blunt point (crayon).  It will form a small ball on the end, but nothing like the pure.  May be the solution to your "violent" arc starts.Syncro 250 DX Dynasty 200 DXMM 251 w/30A SG XMT 304 w/714 Feeder & Optima PulserHH187Dialarc 250 AC/DCHypertherm PM 1250Smith, Harris, Victor O/ASmith and Thermco Gas MixersAccess to a full fab shop with CNC Plasma, Water Jet, etc.
Reply:green is what I have been using
Reply:im kida thinkin that I was not doing a great job of grinding the tungsten.With a little more care the problem seems to be not as pronounced, one thing i am noticing is the welds theemselveshave little pits on them as if someone quickly sandblasted the weld. I would post pics but I cant find the memory card to my camera, Using 4043 rod. The welds look pretty good except for that
Reply:Grinding? please correct me if I am wrong guys, but you should be balling the end on pure tungsten AC welding. i use ball ends on my syncro 180 and my welds look decent and have good penetration. been welding 1/8 inch today. 120 amps, AC, ball end, pure tungsten, 15cfm argon
Reply:Originally Posted by phyisisist777Grinding? please correct me if I am wrong guys, but you should be balling the end on pure tungsten AC welding. i use ball ends on my syncro 180 and my welds look decent and have good penetration. been welding 1/8 inch today. 120 amps, AC, ball end, pure tungsten, 15cfm argon
Reply:Lanthanated tungsten is red, correct? I also changed my balnce control to 7
Reply:ah...that is a good point. pure tungsten is a bit hard to start compared to lanthanated. I like the how pure tungsten maintains the ball though...
Reply:benchracer,No.  Thoriated is red.  2% Lanthanated is blue.I don't like the red for aluminum, expecially on a Sync (transformer).  The red will form multiple small balls on the tip (and sometimes split) on a non-inverter machine.Some tiggers still use the green on the inverters (such as the Dynasty), but they're using sine wave waveform rather than a soft squarewave (which is what your Sync provides).Syncro 250 DX Dynasty 200 DXMM 251 w/30A SG XMT 304 w/714 Feeder & Optima PulserHH187Dialarc 250 AC/DCHypertherm PM 1250Smith, Harris, Victor O/ASmith and Thermco Gas MixersAccess to a full fab shop with CNC Plasma, Water Jet, etc.
Reply:I use nothing but 2% ceriated. --Gol'
Reply:Originally Posted by Go1lumI use nothing but 2% ceriated.
Reply:On all machines, transformer based and inverter. Sharpened to a point. --Gol'
Reply:strangely enough I am having better luck with aluminum than steel. Is there any good books on tig exclusively?Last edited by benchracer1; 12-05-2010 at 03:55 PM.
Reply:http://www.millerwelds.com/pdf/gtawbook.pdf or http://www.millerwelds.com/resources...&submit=Searchor google pdf's
Reply:If  I could find my camera I would post a pic. I have been running some practice beads on 1/16 mild steel using no filler. The back side of the metal actually looks like it has had the bead run on it. I fi reduce the heat (amps) the weld appears a bit to cold. I have been using red tunsten 75 amps. Is that satisfactory to have that bead look on the back of the metal. If I can find my camera I will post pics
Reply:Well I figured out part of my problem. The steel is only .040, not 1/16th. What is the thinnest sheet metal that is satisfactory to practice for a new guy? I primarily want to work with sheet metal.