Gas Selection For Aluminum Gas Welding; Gas Selection For Stainless Steel Welding; Gas Selection For Steel Welding With Silicon Bronze Wire; Select Welding Current Polarity - Sears MIG Wire Feed Welder Welding Instruction Manual

mixture o f75% Argon and 25% Carbon
Dioxide, though 1 00% Carbon D ioxide is
also acceptable. DONOT USE Argon
gasconcentrations higher than75% on
steel. T heresult willbeextremely poor
penetration, porosity, andbrittleness of
weld.
This gasmixture h elps t oprevent burn
through a nd distortion onvery thinsteel
yetprovides good penetration onthicker
steel.Itsability t ominimize spatter
results i nclean, smooth w eld
appearances. Inaddition, itprovides
good puddle c ontrol when welding
vertically oroverhead. This gasmixture
isavailable pre-mixed ina single cylinder
from your l ocal g asdistributor.
Gas Selection For Aluminum Gas
Welding
Our onlyrecommendation for shielding
an aluminumweld is pureArgon. Do not
attemptto use the Argon/Carbon Dioxide
(recommended for steel) when welding
aluminum.
Gas Selection For Stainless Steel
Welding
The best shielding gas for stainless steel
weldingis a mixtureof 90% Helium,
7.5% Argon, and 2.5% CarbonDioxide.
However,the 75% Argon, 25% Carbon
Dioxidemixture(recommended for steel)
can also be used,but an increasein the
area beingheated bythe arcwill be
experiencedcausingslightlygreater
distortion of the base metal. Also this
mixturecan cause a decrease in the
abilityof the stainlesssteelweld to resist
corrosion. Eithermixturecan be
obtainedin a singlecylinderfrom your
local gas distributor.
NOTE: Potential shielding gas
problems.
1.
DEFECTIVE GAS - Just like any
other product, a cylinder of gas can
be defective. Moisture or other
impurities in the gas can create
dirty, porous, brittle welds with
.
greatly reduced penetration. The
only remedy is to replace the
cylinder.
INSUFFICIENT SHIELDING GAS
COVERAGE - This problem can be
created by several causes. The
symptoms are a dirty, porous,
brittle, and/or non-penetrating weld.
Refer to your WELDER USER'S
GUIDE for corrective action.
Gas Selection For Steel Welding With
Silicon Bronze Wire
Use onlypureArgon when weldingsteel
with Silicon-Bronze wire.
SELECT WELDING CURRENT
POLARITY
Direct current (dc) reversepolarity is
required when usinggas-shieldedsteel
weldingwires. Direct currentstraight
polarity is usedwith self-shielding flux
coredwires. Depending on the
configuration of your welderas it was
manufactured, you may need to convert
the polarityfor thetype of wire you will
be using. (Note:someweldersdo not
have the capability of changingthe
polarity.)
Direct current reverse polarity is
sometimes referred to as DCEP (Direct
Current Electrode Positive) and dc
straight polarity is sometimes referred to
as DCEN (Direct Current Electrode
Negative).
PREPARING THE WORK
AREA
An important factor in making a
satisfactory weld is preparation. This
includes studying the process and
equipment and then practice welding
before attempting to weld finished
product. An organized, safe, convenient,
comfortable, well-lighted work area
should be available to the operator. The
work area should specifically be free of
all flammables with both a fire
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