Sheet metal and tungsten size?

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I need a little insight from the pro's here. I have been welding up some 16 and 18 gauge mild steel on an old car project I am working on. I am using a lincoln 185 tig. I started with a .20 size tungsten and was blowing through, even turning the machine down to 10amps. After being frustrated I moved to scrap pieces and changed my tungsten to a 1/8th size. I got much better results. In fact I didn't blow through once and I was using more amps? I am an intermediate TIG welder with not much experience on the thin stuff. I ground both the tungstens to about 2.5 the size to a sharp point. Can anyone provide me with a little knowledge to why this is happening? This going against what I thought I knew?!? Thanks.
Reply:Your tungsten is twice the diameter as the thickness of the metal! The larger the tungsten, the more current it needs for arc stability. .001" thickness = 1 amp current. 16 gauge = .06, so start around 60amps. Try using a .062, or at most, .093 dia. tungsten, and lower amps. ------------john
Reply:What was the first tungsten size, .20?  Assume this is a typo.Are you pretty sure of what's happening here, Tungsten #1 blows through at 10 amps, and Tungsten #2 does not blow through with 10+ amps?Are you using a foot pedal current control, how do you know what the amperage is?If you're talking the difference between 1/16 and 1/8" tunsten, or even 0.040 and 1/8", both ground to a sharp point, I don't think this is your problem.Assume you are attempting to control arc length, travel speed, and torch angle, the same for both welds.Is the scrap metal sitting on a metal table that may act as a heat sink?  Can you try a controlled experiment on one piece of steel, only changing the tungsten, NOT CHANGING ANYTHING ELSE?  And as Zap say's, PIC's would help a bunch.This may seem unbelivable, but the two different steels may be the cause of your frustration.  More on this later.
Reply:I typo'd both the tungsten sizes! I started with a .040 size and moved to a 1/16th. Sorry about that. I am using a foot control, and I also did suspect that the base metal might be a problem. I setup the same weld, same amperage, gas flow rate, just changing the tungsten and I burned throught with the smaller size.  I don't have a digital camera, I wish I did because I have an single bead with a good example of what I experienced. The only other half ***'d guess I had was that a smaller tungsten was focusing the arc more than the larger one which was causing it to burn through? I also thought the .040 tungsten could be the root cause I my problem. It's a tiny little sucker and my grinding techniqe could be the root cause. I will give it a try again tonight and see if my neighbor could lend me their camera for the night. Thanks again.
Reply:Whats your start current set at?  Does it have a ramp up feature (not familiar with your welder).  It could be set up at like 30 40 amps and soon as you stomp the pedal, 'poof'.Various GrindersVictor Journeyman torch200cf Acet. 250cf oxygenLincoln 175 plus/alpha2 gunLincoln v205t tigLincoln 350mpEsab 650 plasmaWhen you can get up in the morning, Its a good day.Live each day like its your last.
Reply:One should not "stomp" the pedal... 1/16" tungestion sharp!Set the welder on the lowest setting and work your way up 10 amps at a time..Turn the gas up a bit..straight argon right?...zap!I am not completely insane..Some parts are missing Professional Driver on a closed course....Do not attempt.Just because I'm a  dumbass don't mean that you can be too.So DON'T try any of this **** l do at home.
Reply:I do get good welds with the 1/16 so I guess I stick with that. I actually finished up the patch panel I was working on with the larger diameter tungsten and it came out really nice. I still am confused to why this would happen. I'm sure I'm doing something wrong, I just cant figure out what?
Reply:Sorry 'bout the stomp (just keep thinking of it as a stomp box all the time).  Gently press the amptrol...Various GrindersVictor Journeyman torch200cf Acet. 250cf oxygenLincoln 175 plus/alpha2 gunLincoln v205t tigLincoln 350mpEsab 650 plasmaWhen you can get up in the morning, Its a good day.Live each day like its your last.