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VIPER MIG 135
OPERATING MANUAL
12.7 Tungsten Preparation
Always use DIAMOND wheels when grinding and cutting. While tungsten is a tough 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 causes the electrons to flow steadily and easily to the end
of the tungsten tip. The arc starts straight and remains narrow, concentrated, and stable.
12.8 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 starts
and eliminates arc wander 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.
12.9
Electrode Included Angle/Taper - DC
Tungsten electrodes for DC welding should be ground
longitudinally and concentrically with diamond wheels to
a specific included angle in conjunction with the tip/flat
preparation. Different angles produce different arc shapes
and offer different weld penetration capabilities. In general,
blunter electrodes that have a larger included angle
provide the following benefits:
• Last longer
• Have better weld penetration
• Have a narrower arc shape
• Can handle more amperage without eroding
Sharper electrodes with smaller included angle provide:
• Offer less arc weld
• Have a wider arc
• Have a more consistent arc
The included angle determines the weld bead shape
and size. Generally, as the included angle increases,
penetration increases and bead width decreases.
TIG: Welding Guide
Grind longitudinal on the
grinding wheel
Don’t grind across
the grinding wheel
2.5x tungsten diameter
Flat tip
Pointed tip
Flat spot
diameter
Included
angle
