Hot Rods Lincoln Squere Wave TIG 175 question

Gentleman: I have a Lincoln purchased new in 2000. Recently when I try to start the arc (mild steel, DC-, 18 cubic feet per hour argon) it dances around everywhere all the way back into the cup and contaminants the tungsten before the arc actually starts. I've checked the points on the high freq (.015), checked all my settings, argon is flowing. The torch is the one it came with Magnum Air cooled LA9. This is going to be a real PITA to load up and take somewhere to have checked out so I thought I'd try here first. Your thoughts? Dave

 

It sounds like your Tungsten is contaminated. Break about 1/2" off and regrind to a 30# point then slightly flatten the point. Also make sure the steel is clean of any coating or mill scale and wipe it down with Acetone.
Another point is what type of Tungsten are you using? I ran a test using all available electrodes and found that a 2% Lanthanated electrode will weld 99% of anything, even Aluminum. I don't even buy pure, Thoriated or Cereated anymore.

 

check your ground.

 

Do what Angie said.
You are running 100 argon right?
How long has it been since you've welded with it and it ran correctly?

 

how much is your stick out and how have you prepped the tungsten?

 

Both replies are good points. I have been using 3/32 2% thoriated tungsten but I recently tried something different, not sure what since I sharpen both ends. Not good practice I know. After checking grounds and going back to a known type of tungsten (2% thoriated-red) things seem to be back to normal. Thanks for your help. Dave39

 

Could be the tungsten collet isn't tight enough. Mine does that every now and again.