erratic arc with new torch parts

[jgorm]

I replaced all the parts on my torch and now the arc is erratic. It comes off the tip from about 5 places and goes sideways a lot. I switched to 3/16" electrode and a #5 cup (i think). I ground the tip, then reground it to be sure but it still does it about 90% of the time. The electrode is pure tungsten, and i was using the red tungsten (1/16) before with no issues. Its DC standard polarity on SS and MS (same on both). Any tips?

[jgorm]

I switched back to the 1/16" red tungsten and it seems to work fine. Any ideas why the fatter electrode would cause me so much trouble?

[Craig in Denver]

Pure tungsten is for AC aluminum welding. I hope you meant 3/32" and not 3/16".

Try a 3/32" red, I use it for most of my hobby welding.

[Pangea]

Yikes! 3/16 tungsten is huge for a hand held torch!

[jgorm]

Pure tungsten is for AC aluminum welding. I hope you meant 3/32" and not 3/16".

Try a 3/32" red, I use it for most of my hobby welding.

Thanks Craig! And yeah, 3/32 not 3/16. I always thought you could use pure tungsten for everything, but it looks like only for aluminum. Is that right? I remember there being 3 colors, red, green (pure), and something else. Do i really need to have all 3 types to weld MS, SS, and Al? Can i get by with just red and green? (yeah, i'm still very new at tig)

[Pangea]

I've been GTAW for about 30 years now and all I've ever used is 2% thoriated (red) for everything. Certified on SS, Ti, Al, ChroMo, Inconel, Waspalloy, Magnesium, all with 2%. Military, Civilian, and the NASA.

YMMV

[jgorm]

I've been GTAW for about 30 years now and all I've ever used is 2% thoriated (red) for everything. Certified on SS, Ti, Al, ChroMo, Inconel, Waspalloy, Magnesium, all with 2%. Military, Civilian, and the NASA.

YMMV

Good to know. I'll see if i can return my unopened green and exchange it for red. Thanks Pangea!!

[Craig in Denver]

Thanks Craig! And yeah, 3/32 not 3/16. I always thought you could use pure tungsten for everything, but it looks like only for aluminum. Is that right? I remember there being 3 colors, red, green (pure), and something else. Do i really need to have all 3 types to weld MS, SS, and Al? Can i get by with just red and green? (yeah, i'm still very new at tig)If you're using a x-former welder, red is all you need. Pure (green) is indeed, for alum. There are more colors than 3. (brown, orange, blue, gold, red, green) If I ever run out of red, I'll try the blue, 2% Lanthanated. They seem to be the newest internet favorite.

[Aeroweld]

As others have commented, Pure (Green band) tungsten is for Aluminum (AC) only. Like others, I use 2% for everything about 99% of the time.

With that being said you can also get a lot of wandering when trying to use too large of a tungsten at low amperage without proper tip grinding. When using a large dia tungsten at low amps you pretty much have to "throw the book out" when it comes to tungsten prep of the tip for good results.

It has not been talked about here that I have seen, but too large of a cup diameter can also lead to an eratic arc at given amperage.