Tungsten Preparation
Always use DIAMOND wheels when grinding and cutting. While tungsten is a very hard material, the
surface of a diamond wheel is harder, and this makes for smooth grinding. Grinding without diamond
wheels, such as aluminium oxide wheels, can lead to jagged edges, imperfections, or poor surface
finishes not visible to the eye that will contribute to weld inconsistency and weld defects.
Always ensure to grind the tungsten in a longitudinal direction on the grinding wheel. Tungsten
electrodes are manufactured with the molecular structure of the grain running lengthwise and thus
grinding crosswise is “grinding against the grain.” If electrodes are ground crosswise, the electrons have
to jump across the grinding marks and the arc can start before the tip and wander.
Grinding longitudinally with the grain, the electrons flow steadily and easily to the end of the tungsten
tip. The arc starts straight and remains narrow, concentrated, and stable.
Electrode Tip/Flat
The shape of the tungsten electrode tip is an important process variable in precision arc welding. A
good selection of tip/flat size will balance the need for several advantages. The bigger the flat, the
more likely arc wander will occur and the more difficult it will be to arc start. However, increasing the
flat to the maximum level that still allows arc start and eliminates arc wonder will improve the weld
penetration and increase the electrode life. Some welders still grind electrodes to a sharp point, which
makes arc starting easier. However, they risk decreased welding performance from melting at the tip
and the possibility of the point falling off into the weld pool.
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