What are the differences between types of tungsten electrodes?

Tungsten electrodes are used in Tungsten Inert Gas (TIG) welding or plasma welding to join various types of metals. The electrodes are nonconsumable and come in a variety of sizes and lengths, and can be composed of pure tungsten or an alloy of tungsten and other rare-earth elements and oxides. The choice of electrode depends on the base material type and thickness, and whether you weld with alternating current (AC) or direct current (DC). The electrodes can be color-coded to eliminate confusion over their type, with pure tungsten electrodes being green. TIG welding creates clean, precise welds and is ideal for welding thin materials and surfaces that will be visible

To begin with, different electrodes have different colored bands that are used to identify them.  However, there are several other important differences to consider when selecting a tungsten electrode.  Here some of the various types with the respective characteristics:

EWTh-2:  2% thoriated tungsten – Red Tungsten Electrodes.  The EWTh-2 tungsten electrode is color-coded with a red band.  It is known for its durability, ability to withstand high currents, and excellent arc starts.  It is primarily welded using a negative polarity and direct current. It does not have great characteristics when welding with AC.

EWLa-2: 2% lanthanated tungsten – Blue Tungsten Electrodes.  The EWLa-2 tungsten electrode is color-coded with a blue band.  It is known for its excellent arc starting ability, excellent current carrying ability, and can withstand many arc cycles.  It can be welded as the negative electrode using direct current or with alternating current.EWP:  Pure tungsten electrode.  EWP is color-coded with a green band.  It has excellent arc stability. It is almost exclusively used with alternating current.  Tungsten emission is more likely with a pure tungsten electrode when compared with other alloyed tungsten electrodes.

EWCe-2:  2% ceriated tungsten – Gray Tungsten Electrodes.  EWCe-2 tungsten electrode is currently color-coded with a gray band, although in the past it was color-coded with an orange band.  It is quite similar to EWLa-2 in that it has excellent current carrying ability, excellent arc starting ability, and can last through many different arc start and arc termination cycles.