25
time length (50%), penetration is reduced and over
-cleaning results in wide etch lines 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 penetration will be re-
quired at times than others. Ordinarily, about 30-
35% electrode positive is considered 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. A
ball is not needed or recommended. Cleaning is still
usually sufficient at a 25% level. The cleaning action
is still visible even at these levels. Settings greater
than 40% will result in balling and a less stable arc.
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 needed, then switch to
a larger size of tungsten that can handle the in-
creased heating level. Signs of too little cleaning
action while welding aluminum include soot, poros-
ity, and dull looking (scummy) welds. A dedicated
stainless steel brush and suitable aluminum clean-
er such as acetone should be used before starting
any aluminum weld to help break up the heaviest
oxide layer so less EP is needed and better penetra-
tion can be achieved.
NOTES:
1. Due to the rapid cycling 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. However, in an
inverter, this is not necessary. So, the HF switch
refers only to the Start of the arc, and not to AC
operation.
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% or arc starts may become more
difficult and erratic.
3. If arc wandering in AC is a problem, reduce
cleaning percent. If it continues, reduce gas
flow and check for drafts, open doors or welder
placement.
4. Yellow-coded AC controls only apply during AC
TIG operation and do not affect DC settings or
plasma cutting.
5. If cleaning action becomes excessive at low
settings, it is likely to be a speed/heat issue and
not machine issue. The longer the electrode
remains in the same place, the more the clean-
ing action will have an effect. If you find your-
self with this issue, try increasing the amperage
to travel faster. If overheating is feared, then
use pulse to increase forward travel speed to
reduce the cleaning. You should only suspect a
welder issue if adjusting the AC balance 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 or Zirconiat-
ed tungsten is NOT being used.
7. Do NOT use pure tungsten or Zirconiated tung-
sten with an inverter to weld in AC or DC mode.
EN 35%
EP 65%
50%
EN 65%
EP 35%
50%
Extreme cleaning setting. 65% EP:
Shallow penetration, balling tungsten, excessive cleaning area.
Good penetration setting 35% EP:
Deeper penetration, sharper tungsten, narrow cleaning area.
EN 50%
EP 50%
50%
Standard transformer welder balance: 50% EN/EP
Balling tungsten, light penetration, wide cleaning area.
1 Hz (one full AC cycle)
EXAMPLE: AC EP (+) BALANCE
30% EP
Narrow bead/etching/sharp tungsten
Cleaning/Frosted Area of Aluminum
50% EP
Wider bead/etching/rounded tungsten
65% EP
Wide bead/
etching/balled
Basic theory and function
Section 3
