Fancy schmancy TIG cups.

[Roadracer_Al]

(09-28-2015, 09:26 PM)arvidj Wrote: I wonder why the AC restriction listed on the box?

The low portion of the AC sine wave is a cleaning phase. Normally, the "dirt" clings to the electrode and a bit to the ceramic cup. Perhaps with a pyrex cup (who's big claim to fame is that you can see through it) would get the dirt "plated" onto the inside of the cup, clouding or completely blocking the view through the cup.