Selecting Shielding Gas; Install The Shielding Gas - Craftsman 196.205080 Manual De Usuario

SELECTING SHIELDING GAS

The shielding gas plays an extremely
important role in the MIG welding process. It
is critical that the molten weld puddle be
shielded from the atmosphere. The shielding
gas creates a protective pocket around the
weld puddle which keeps impurities in the air
from infecting the weld. Inadequate shielding
will result in porous, brittle welds.
Although there are many gasses and gas
mixtures available for MIG welding, the
following recommendations are based on the
electrical output characteristics and metal
thickness capabilities of this specific
MIG welder.
Gas Selection For Steel Welding With
Steel Wire
For either mild or low carbon (High Strength
Structural) steel, use a gas mixture of 75%
Argon and 25% Carbon Dioxide. DO NOT
USE Argon gas concentrations higher than
75% on steel. The result will be extremely
poor penetration, porosity, and brittleness
of weld.
This gas mixture helps to prevent burn
through and distortion on very thin steel yet
provides good penetration on thicker steel.
Its ability to minimize spatter results in clean,
smooth weld appearances. In addition, it
provides good puddle control when welding
vertically or overhead.
Gas Selection For Stainless Steel Welding
The best shielding gas for stainless steel
welding is a mixture of 90% Helium, 7.5%
Argon, and 2.5% Carbon Dioxide. However,
100% Argon can also be used, but an
increase in the area being heated by the arc
will be experienced causing slightly greater
distortion of the base metal.
Gas Selection For Steel Welding With
Silicon Bronze Wire
Use only pure Argon when welding steel with
Silicon-Bronze wire.
Gas Selection For Aluminum Welding
With Aluminum Wire
Use only pure Argon when welding alu-
minum.
12 12

INSTALL THE SHIELDING GAS

WARNING
IMPROPER HANDLING AND MAINTE-
NANCE OF COMPRESSED GAS CYLIN-
DERS AND REGULATORS CAN RESULT
IN SERIOUS INJURY OR DEATH!
Always secure gas cylinders to the welding
cart, a wall, or other fixed support to prevent
the cylinder from falling over and rupturing.
Read, understand, and follow all the COM-
PRESSED GASSES AND EQUIPMENT
HAZARDS in the SAFETY SUMMARY at the
front of this manual. Secure your gas cylin-
der to the welding cart, or other fixed sup-
port.
1. Remove the protective cap from the cylin-
der and inspect the regulator connecting
threads for dust, dirt, oil, and grease.
Remove any dust or dirt with a clean
cloth. DO NOT ATTACH YOUR REGULA-
TOR IF OIL, GREASE, OR DAMAGE
ARE PRESENT.
2. Open the cylinder valve FOR JUST AN
INSTANT to blow out any foreign matter
inside the valve port. Never aim the open
valve cylinder port at yourself or
bystanders.
3. Screw the regulator into the cylinder
valve and tighten with a wrench.
Note: If the cylinder you have is equipped
with male regulator connecting threads
instead of female, you will need to obtain a
special compressed gas cylinder adapter
from your gas supplier to install between
your gas cylinder and regulator.
4. Firmly push the gas hose over the barbed
fittings on the back of the welder and on
your regulator.
5. Secure both ends of hose onto barbed fit-
tings with hose clamps.