Originally Posted by JamesCH95 (Post 1128226)

It would force the arc to be longer, increasing the weld arc's work function energy, making the pool hotter. However, the longer arc is less stable and more heat can be added by turning up weld current, which is better in terms of arc control.



It's not just welder preference. The balled end of a pure tungsten electrode is molten and more likely to contaminate the weld with tungsten, particularly if the molten tungsten drips into the weld pool. This a REALLY bad problem if you want to do any post-weld machining, tungsten doesn't machine so well :D

The ground point on an red/orange/silver electrode control the arc better than the balled end on a pure tungsten electrode, and they can handle more heat/current.