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Section 3
running parallel to the side of the weld. Not all
weld conditions will be alike, so more cleaning is
required at times than others. Similarly, more pen-
etration will be required at times than others. Or-
dinarily, about 30-35% electrode positive is consid-
ered an ideal amount (65-70% electrode negative).
This means that more heat is put into the work
than is placed on the tungsten. A sharper point can
be used. Cleaning is still sufficient at that level.
Good results can be achieved with about 30% EP.
The cleaning action is still visible at this level but
usually not excessive. Ideally, the cleaning action
should be adjusted until a small amount of frosting
can be seen no more than 1/8" distance from the
edge of the weld. If a piece of metal is particularly
heavily oxidized or dirty, more cleaning action will
be required. If too much cleaning action is used,
the tungsten will begin to ball and even may start
to burn away. If this much cleaning action is need-
ed, then switch to a larger size of tungsten that
can handle the increased heating level. Signs of
too little cleaning action while welding aluminum
include soot, porosity, and dull looking (scummy)
welds. A dedicated stainless steel brush and suita-
ble aluminum cleaner such as acetone should be
used before starting any aluminum weld to help
break up the heaviest oxide layer so less EP is need-
ed and better penetration can be achieved.
EXAMPLE: AC EP (+) BALANCE
1 Hz (one full AC cycle)
EN 50%
50%
Standard transformer welder balance: 50% EN/EP
Balling tungsten, light penetration, wide cleaning area.
EP 65%
EN 35%
50%
Extreme cleaning setting. 65% EP:
Shallow penetration, balling tungsten, excessive cleaning area.
50%
EN 65%
Good penetration setting 35% EP:
Deeper penetration, sharper tungsten, narrow cleaning area.
EP 50%
EP 35%
Basic theory and function
Cleaning/Frosted Area of Aluminum
NOTES:
1. Due to the rapid switching of the inverter, High
Frequency (HF) is not used except to start the
arc. In a transformer welder, the HF would re-
main on to stabilize the AC arc, but in an invert-
er, this is not necessary. So, the HF switch refers
only to the Start of the arc, and not to AC oper-
ation. However to reduce tungsten contamina-
tion, you should only operate the AC mode with
the HF start selected.
2. The addition of Helium to Argon can increase
the welding capacity of the welder and alter the
amount of cleaning typically needed. Do not
exceed 25% however or arc starts will be diffi-
cult and erratic.
3. If arc wandering in AC is a problem, reduce
cleaning percent, then if it continues, reduce
gas flow and then check for drafts.
4. Yellow-coded AC controls only apply to AC op-
eration, and do not affect the settings on DC.
5. If cleaning lines are excessive at low settings, it
is likely not a welder issue, but rather, a speed/
heat issue. The longer the electrode remains in
the same place, the more the cleaning area
will widen. If you find yourself with this issue,
try increasing the amperage to travel faster. If
overheating is feared, then use pulse to in-
crease forward travel speed to reduce the
cleaning lines. You should only suspect a weld-
er issue if adjusting the AC balance to above 40
-60% does not begin to ball the tungsten.
6. If tungsten balling is experienced at settings
below 40%, make sure that the torch is in the
negative connector and that pure tungsten is
NOT being used.
7. Do NOT use pure tungsten or Zirconiated tung-
sten in an inverter to weld in AC or DC mode.
22
30% EP
Narrow bead/etching/sharp tungsten
50% EP
Wider bead/etching/rounded tungsten
65% EP
Wide bead/etching/balled tungsten
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