E3 Tungsten Electrode - Purple Tip
1/16" x 6" (1.6mm x 150mm)
ANSI/AWS A5 12-92 - BS EN 150 6848:2015
For many years 2% Thoriated Tungsten (Red tip coloured electrodes) was the preferred choice for DC electrode negative welding. Thorium is slightly radioactive and contains very small trace levels of naturally occurring isotopes that emit alpha particles at a very long half-life. Due to the increased awareness and trends to eliminate all radioactive sources (even at safe levels) from the work environment, some welding communities prefer using non-radioactive alternatives.
E3 electrodes are also claimed to run much cooler providing faster and reliable arc starting and an extended tip life.