I work as a welder/fitter in the aluminum division of Vertex RSI Antennae products. We make quite extensive use of the GTAW process in the fabrication of aluminum products. (AC high freq.) We are provided with 2%thoriated electrodes, however I know that pure tungsten is typically reccomended for use on aluminum. Granted, thoriated electrodes have higher current capacity but their propensity to collect impurities and therefore cause a an erratic and poorly directed arc seems to negate this benefit. (The "cauliflower syndrome") In light of this issue, I have several questions: What benefit,(besides current capacity/electron emission) does the use of thoriated electrodes provide? In addition, do thoriated electrodes present an increased risk of weld discontinuities in aluminum? Any information, or recommended reading on this subject would be helpful.

Thanks