Full Product Manual

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switch to a larger sized tungsten that can handle the
increased heating level. Signs of too little cleaning
action while welding aluminum are sooty, black or
dull looking welds. (In MIG some soot is normal
while welding aluminum.) A dedicated stainless
brush and suitable aluminum cleaner such as ace-
tone should still be used before welding any type of
aluminum to help break up the heaviest oxide layer
so less EP is needed and better penetration can be
achieved. Even if the aluminum has a mirror like
shine, it is still oxidized.
vides penetration in the TIG welding process. Elec-
trode positive (EP) creates a strong reverse flow of
electricity that breaks up the weld-resistant oxidation
that covers aluminum and magnesium components.
AC Balance. The AC output is formed by rapidly
alternating polarity between electrode negative and
electrode positive, creating something that resem-
bles a wave when viewed on an oscilloscope. Nor-
mally, with standard transformer welders, both
standard sine wave and even square wave welders
have little or no way to change the ratio of EN to EP,
which results in welding with a molten ball at the
tip of the tungsten and a less stable arc. Electrode
negative (EN) provides penetration in the TIG weld-
ing process. Electrode positive (EP) creates a strong
reverse flow of electricity that breaks up the weld-
resistant oxidation that covers aluminum and mag-
nesium components also places a lot of heat on the
tungsten. In a “balanced” wave where both EP and
EN are equal in time length (50%), penetration is
reduced and over-cleaning results in wide etch lines
running parallel to the side of the weld. Not all
welds conditions will be alike so more cleaning is
required at times than others. Similarly, more pene-
tration will be required at times than others. Ordi-
narily, 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
on the tungsten and a sharper point can be used.
Cleaning is still sufcient at that level. Good results
can be achieved with about 30% EP or less. The
cleaning action is still signicant even at these lev-
els. 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 truly needed, then
200 Hz
60 Hz
Cleaning/Frosted Area of Aluminum
65% EP
Wide bead/etching/balled/consumed tungsten
50% EP
Wider bead/etching/balled tungsten
30% EP
Narrow bead/etching/sharp tungsten
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
TIG OPERATION AND THEORY
Section 3 Basic Theory and Function