Tungsten problems on Dynasty 700

Greetings all,
First of all, this machine is GREAT! The control in AC with the pulser is incredible. After some initial problems with torches,(We did not need the
700 amp rated torch that came with the machine, 250 is working just fine. Add to that the reluctance of our tool room guy to buy the correct set up, we attempted to "Frankenstein" a set up together, need I tell you how that worked out?) We are now rolling right along with one of the smaller 250 amp Miller torches and life is mostly good.
Now for the question; When welding in DC, usually SS, I can not keep a decent point on my tungsten. 3/32" 2% Thoriated tungsten, ground to "pencil point" erodes like crazy, a simple 1 to 1 1/2X diameter or so grind yields a slightly longer lifetime, but it tends to ball slightly and I lose alot of arc control. Running DCEN with or without pulser doesn't seem to matter.
So, any ideas? Am I missing something in the directions or use of the machine? As always, any and all help is greatly appreciated.
Regards, Jim
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wrote:

What amperage level are you welding at? and how thick?
3/32" Red (2% Thoriated) Tungstens on DCEN usually have a recommended amperage of around 200ish amps (miller tig documentation says 135-235)
Is the machine at full amperage and heavy pedal? or backed down to around 200-250 amps if your TIG uses full pedal?
Pushing too much Current through a tungsten thats too small will make it start to melt and erode the point I've seen it happen with 1/16ths on my machines the size of tungsten is a factor in power handling as is polarity.
If youre doing stuff that NEEDS the dynasty 700 over a dynasty 200 or 300 you might well be using too small a tungsten
There are experts ont he group who can explain it better but i know from experience that the more amperage and heat is passing the bigger the tungsten needs to be (Because AC and DCEP put more heat int he torch the tungsten needs to be sized up too for the same welding amperage)
Brent P Ottawa Canada
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Two questions...are you SURE its straight polarity? And are you sure you are NOT using C25 mig gas?
I got a tank of "argon" once..that was mis labled. The CO2 burned the electrodes off quickly.
Gunner
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Try switching to Lanthanated tungstens and make sure your tungsten is large enough.
If you are running more than 200 amps then move up to a 1/8" or even a 5/32" tungsten.
BTW at higher amps remove the sharpest part of the tip before using.
A tiny flat on the tip will reduce tungsten erosion at higher amps.
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news:stagesmith->

I wish, Ernie. Unless I can get the Big Boss Man to say the word, our before-mentioned tool room guy will not buy anything but what he has for 15 yrs. I have tried mentioning both Lanthanated and Zirconated, just got the Deer-in-the-headlights look. GGRRRR!!

Sorry, I didn't mention the amperage. Mostly I am in the 80-100 amp range, maybe 120 if I am welding a 1/4" foot to a piece of 1/8" wall tubing.

I am familiar with truncuating(sp) the tungsten for higher amperage, but thanks for the reminder.
Thanks as always, Jim
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