Miller Electric DB1812R Owner's Manual page 10

Trouble
Wandering arc
Yellow powder or smoke on cup.
Erratic arc
Porosity in weld.
OM-1603 Page 8
Shield weld zone from drafts.
Reduce gas flow rate.
Select proper size and type tungsten. Properly prepare tungsten according to Section 5.
When using AC, check welding power source High Frequency control setting, and increase setting if nec-
essary.
Use proper type shielding gas.
Check for proper gas flow rate. Check manufacture's recommendations.
Increase postflow time.
Check torch cup size. Match cup size to joint being welded.
When using DC, check polarity, and/or polarity of welding cables.
When using AC, check welding power source High Frequency control setting, and be sure it is operating
continuously.
Select proper size and type tungsten. Properly prepare tungsten according to Section 5.
Use proper arc length. Arc length may be too long or too short.
Make sure base material is clean and free of contaminates.
When using AC, slow travel speed can cause erratic arc. Adjust travel speed.
Check for proper gas flow rate. Check manufacture's recommendations.
Check and tighten gas fittings.
Make sure base material and filler material is clean and free of contaminates.
Check for impurities and moisture in gas lines. Purge if necessary.
If torch is water cooled, check torch and cables for water leaks. Repair or replace if necessary (see Sec-
tion 4-1).
Remedy