EWTh-2 The higher thoria content in the EWTh-2 electrode causes the operating characteristic improvements to be more pronounced than on the lower thoria content EWTh-1. The additional thoria also provides about 20 percent higher current-carrying capacity, longer life and resistance to contamination of the weld. Should it be desired to use these electrodes for AC welding then balling can be accomplished by briefly, and carefully welding with DC electrode positive prior to welding with AC. During AC welding, the balled end does not melt and so emission is not as good as from a liquid ball on an EWP electrode. Note: if electrode grinding is used, special precautions relative to ventilation should always be considered to avoid ingestion of radioactive dust.