Severe arc wander on aluminum....

By CDIZX3 Date 02-04-2005 01:41

First off i have a Thermal Arc TSW175 TIG welder. It has wave control and pulser. My problem is...i normally have no problem welding 1/8" aluminum. When i try ANYTHING less than that....I get real bad arc wander. The arc just seems to spin around the tungsten about a 1/4" away. If i give it more amps...the situation get better, but then i'm so hot i start melting thru. It's impossible to make a nice bead. I'm using 3/32" Lath. tung. with 1/16" filler. Maybe my tungsten is too big? Maybe grinding it wrong? Maybe settings are wrong? What kinda amps should i be at? Thanx in advance.

By SA-200

Date 02-04-2005 03:27

Try a green tungsten...

By backpurge (*)

Date 02-04-2005 10:51

The tungsten may be a bit on the large size. You could try grinding your tungsten to a point as you would for welding stainless and then stike an arc on a piece of scrap plate, if the end of the tungsten doesn't ball over straight away gently increase the amps till it forms a small ball on the end then revert to your original setting to carry out the actual welding job.

Also, are you cleaning all the surface oxide off the ally. If you are, you may find the arc will be more stable if you leave a thin layer of oxide on the surface.

Cheers - Bob

By Brand X (*)

Date 02-04-2005 16:27

Try a red tip tungsten (thoriated) just to see if the arc stays the same.
Try setting you hot start tig up a little. I think you can with the foot pedal hooked up? Use 3/32 filler rod too. Some blue tips ones in 1/16 would be good to have around for better arc starts. Stay away from pure green on that machine. You need a point with a little flat ground on your tungsten and green does not cut it.

Order some tungstens from these guys that are pre-ground.
Try some of their tri-mix ones too.

http://www.diamondground.com/

By Lawrence (*****)

Date 02-04-2005 18:25

Brand X is right!

Diamond Ground has a guidebook which you can download or print off that is about the most accurate guide around.
http://www.diamondground.com/howto.html

If your torch is water cooled than try 1/16 (0.063) Zirconium, it still has the best low amperage AC arc performance, especially with a pointed tip. Remember to avoid the long slim tapers and go with a more radical angle. Thorium is ok as long as you don't overheat it. Thorium will not form a ball when it gets hot, rather it cracks or sprays into your weld metal. Cerium the #2 choice and best if your torch is air cooled. If you have pure tungsten (green) toss them.

I checked out the owners manual for the TSW185 http://www.thermadyne.com/tai/literature/pdfs/service/430429_503.pdf (check page 24) and if yours has similar features than you should increase your AC frequency when arc wander becomes a problem.. Normal AC runs at 60 Hz. Try increasing your AC frequency to someplace between 120 and 200 Hz. This should have the effect of "stiffening" your arc and making it more directional.