30
BASIC MIG OPERATION
cleaner with chlorinated solvents or death or serious injury may
occur! Pre
-
Clean stripped Aluminum with a dedicated Stainless
Steel Brush to remove oxidation, even if metal is bright and appears
clean. Aluminum will create an oxide layer quickly. Aluminum
such as diamond plate tread with mirror finishes has an oxidized
surface. Finish Aluminum with Acetone, or Aluminum cleaner de-
signed for welding.
A Steel MIG wire such as ER70S
-
6 or ER70S
-
2 includes a sufficient
level of deoxidizers such as silicone and copper that are formulated
to allow it to handle minor to moderate amounts of rust and mill
scale. These deoxidizers will float out most moderate amounts of
contaminates out of the weld and will appear in the usual form of
glassy like deposits on top of the cooled metal. They are easily
brushed off before starting the next pass. They should not be
welded over. Any pinholes that appear are a result of trapped gas
in the weld and should be ground out before the next pass. It
should be noted that some MIG wires such as ER70S
-
3 have low
levels of deoxidizers and must be thoroughly cleaned and ground
before welding.
Multiple Pass Welds.
One of the common misunderstandings that people have when
beginning to MIG weld is that if the welder has the power, then a
single heavy pass will do to weld up in a single pass. This is a
primary way to introduce cold lap and incomplete fusion to the
weld. Single pass welds should not exceed
1/4”
even with the
heaviest wire the welder is capable of handling. A thick pass may
also begin to cool before contaminates and gas pockets have the
time to float out to the surface. It
’
s far better to make multiple
smaller passes to complete a plate weld for a higher quality result.
For best results, this requires that most joints
1/4”
and over be
prepared with a grinder to accept multiple weld passes. The weld-
ment edges should be ground to form a V, U or J shaped groove to
create a recess where the welds can be welded one on top of an-
other. For welding with
.035”
wire and under, create a bead no
thicker than
3/16”
in a single pass, no more than
1/8”
with
.030”
wire, and with
.025”
wire and smaller no more than 3/32 for best
results. This will help maintain proper fluidity of the weld and
prevent gas from being trapped in the weld and give time for any
minor contaminates to float out of the weld. It will also help to
maintain reasonable forward travel speeds. Too slow of travel
speeds will create excess build up and can tend to create cold lap at
the weld toes resulting in poor tie in. One issue created with a
weaving technique even if the metal deposited is the correct thick-
ness s that it can slow the forward progress down. If weaving is too
wide, one side of the puddle will cool and oxidize before the torch
is brought back across to that side. This is a point where porosity
and inclusions can be introduced.
Section 2 Setup Guide
Содержание Power i-MIG 353DPi
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