balling tungsten after grinding?

[andy456]

Recently bought cobel 200 amp ac/dc of ebay to learn ally welding on a fast learning curve as iv got a customers loading ramps to repair. Spent time laying stringers on plate for a start with good success. Moved onto repair and all though decent welds when i change/resharpen tungsten after contamination i use old school balling ie; clearance + flat out arced over clean ally to ball up end, then back to 0.5-1.0- some times the arc wont focus tightly tends to wander for a bit then sorts its self out?? Tungsten 2% thoriated 2.4mm on 3mm parent lap jointing 3mm on top.

 

[Paul.]

some times the arc wont focus tightly tends to wander for a bit then sorts its self out?? Tungsten 2% thoriated 2.4mm on 3mm parent lap jointing 3mm on top.

There's most likely your problem, for AC you really want a zirconiated tungsten, or you could try one of the so called multi strike ones, ceriated or lanthanated.

 

[shenion]

On aluminum, thoriated seems to act like a magnet for contamination. It does work an I use it sometimes, but not ideal.

You want, pure, zirconiated or lanthiated for AC.

 

[andy456]

cheers lads will try. Thanks