Welding on DC, ceriated / thoriated tungsten keeps "balling up"

[RobK]

Arc lengths and brushing...

From what you guys are saying, I am using an arc length that is too long. For the 1.6mm tungsten, I am using an arc of about 4 to 6 mm long (!?), and I am poking the filler rod very close to the arc when I am dipping it in th weld pool. If I have to avoid touching the arc with the filler rod, does that mean I need to be pulling the arc back along the weld by 3 or 4 mm to give me a clear shot at the weld pool, or should I be trying to "slide it down the bank" and into the pool edge?

The picture that I posted was brushed with wire brush before photographing it. It may have been clearer without doing that. The picture is a lot more brown/orange than the real lighting situation created, due to not setting the camera to "indoor tungsten lighting" before taking the photos without flash.

Cheers,
Rob

 

[hotrodder]

If you haven't already, read all of the Miller TIG resources. Pay attention to the 'angles of attack' for the torch and (especially) the filler. Filler is added to the leading edge of the puddle, angle needs to kept low or it'll melt before it reaches the puddle. It IS in very close proximity to the arc but increasing the arc length can actually make things worse- the arc is cone shaped, as arc length increases it fans out more and is more likely to melt the filler before it reaches the puddle.

If your filler has a ball on the end that's a dead give away, should be a cleanly melted edge. Torch movements are covered in the link but there's no back tracking, to begin with it's a pause, add filler, move forward, pause, add filler. As you get to grips with the process you just move forward at a steadyish pace