[samples]

Just recently when I start tigging the "flame" shoots out of the cup, on the inside diameter, and not from the tungsten unless I rapidly increase the amps. This happens with new cups and new electrodes, no matter what size. My machine is a Lincoln (stick/tig), sq wave, 175 amp, PRO. Argon is set at 12-15 lpm
This has caused a couple of cups to "shatter" and puts arcing marks on the work.
any suggestions as to what might be the problem?

[admin]

not really sure, but here are some thoughts.

try pre purging by tapping the foot pedal to get the argon flowing
try using a standard collet body vs gas lens and see if one is better
what type electrode? 2% thor? cer? lanthanated? pure?
does it do it on both ac and dc?

[samples]

I'm using the standard ceramic (pink) gas shields, pure tungsten (for steel) and DC neg. Yes it does do it on AC occasionally when I'm doing aluminum, but not as bad. I can finish a short weld, pause, and when I start again, it does the same thing, so I know the gas is there. Also, my unit does a pre-purge as soon as I turn it on. Don't know if it makes a difference, but sometimes I have to, physically, touch the cup to the work before the arc will start. I'm thinking that my thumb control is not letting enough current through to start the arc.
I asked a local welder about the arc problems and he told me that his does the same thing, once in a while, but he doesn't know what causes it. He uses a large, industrial type, Miller machine with all the various control knobs and his is water cooled.
I'll be going to my local (40 miles away) welding supply shop, for some cups, electrodes, electrode holders and collets, later this week and I'll ask them. If they can give me the answer, I'll let you know.
It's a mystery to me.

[admin]

ditch the pure and go to a 2% thoriated very sharp pointed electrode.
I will bet money, most if not all of your problems will go away.

If you are concerned about the thorium then, 2 or 1.5 percent lanthanated is almost as good

[metalworxs]

i have a lincoln 185 machine and it does the samething when i have a poor ground... try moving your ground as close to the work area as possible and see if that helps....

[metafos]

Try increasing your argon pressure , make sure the collet is tightly secured, a loose collet won't make a good arc transfer to the electrode.

[metafos]

You might also want to check your overall tank pressure, if it's too low, get a fresh tank. Low tank pressure= crappy welds, especially on aluminum.

[welder689]

I have the same machine...Lincoln Square Wave TIG 175 Pro...actually, it's my second one. I've never had this problem and I've used them A LOT...for over ten-eleven years. Interesting.

[DOC]

I was the original poster on this subject. Since then I have switched to 2% Tr. and changed to newly purchased cups. The problem has stopped, but I still don't know what the cause was. The newly purchased cups haven't been getting as dirty on the inside, either.
I'm trying to figure out what difference the 2% Tr made on steel. Hasn't pure Tn been used for "centuries" without problems?

[LightningStalker]

Plasma is strange. It prefers to break out from sharp points. If the cup material is porous or the slightest bit conductive, an arc will travel right over or through it. Porous ceramic can actually conduct a plasma arc better than air because areas of high charge concentration form around the grains. The grains also take up space that would otherwise be air and make a shorter path. Also, the voltage can vary at different points along a "wire" if there is high frequency "ringing" going on. So there could actually be a dead spot at the end of the tungsten and a high spot on the collet. I'm guessing maybe a combination of these things was causing your problem.

Most guys use the 2% and it's actually harder to find anything else. Maybe that was different in the past, but that's the way it is now. Watch the Chernobyl videos on YouTube. Radiation is nothing to be messed with.

[welder689]

I use 2% thoriated tungsten for all of my DC TIG welding...mild steel, stainless, chrome-moly, etc...have been for almost thirty years.

I prefer pure tungsten for aluminum (nothing personal Jody). I like the way it balls up. I once was a welder in a custom machine shop (1993-1994) and they only bought 2% thoriated which we used on everything...My machine there was a Miller Synchrowave 250...I just didn't like using the 2% for aluminum on AC.

Maybe, it's just me though...I know some good welders that use 2% for everything.

[brian]

If your running reverse polarity "electrode positive" on accident, you'll be putting too much heat in the torch and break your cups. If thats it, change to DC -. Could be something that simple.

[rickgct]

i have a miller diversion 165.
sometimes when i lift my finger from the torch switch to stop welding, the arc doesn't stop
i have to pull the torch away from the work piece.
when this happens, the arc will start again when i get close to the piece without
pressing the switch.
this only lasts momentarily, but has caused me to burn through and ruin my work.
other times it works perfectly.
dealer says he has never seen this
any suggestions
the button is not sticking down.