8785115
200A Multi-Process Welder with LCD Display
V4.0
36
For technical questions call 1-800-665-8685
Use a smaller diameter wire for thin base metals. For thicker materials use a
larger wire diameter and larger machine, check the recommended welding
capability of your machine.
As a guide, refer to the Welding Wire Thickness Chart in Table 3.
GAS SELECTION
The purpose of the gas in the MIG process is to protect/shield the wire, the arc and
the molten weld metal from the atmosphere. Most metals when heated to a molten
state will react with the air. Without the protection of the shielding gas, the weld
produced would contain defects like porosity, lack of fusion and slag inclusions.
Additionally some of the gas becomes ionized (electrically charged) and helps the
current flow smoothly.
The correct gas flow is also very important in protecting the welding zone from the
atmosphere. Too low of a flow will give inadequate coverage and result in weld
defects and unstable arc conditions. Too high of a flow can cause air to be drawn into
the gas column and contaminate the weld zone.
USE THE CORRECT SHIELDING GAS
Mild Steel
- CO
2
is good for steel and offers good penetration characteristics;
the weld profile is narrower and slightly raised than the weld profile obtained
from an Argon/CO
2
mixed gas.
Argon/CO
2
mix gas offers better weld ability for thin metals and has a wider
range of setting tolerance on the machine. A combination of 75% Argon, 25%
CO
2
is a good all round mix suitable for most applications.
Stainless Steel
- A mix of 90% Helium, 7.5% Argon and 2.5% CO
2
Aluminum or Bronze -
Use 100% Argon
ALUMINUM WIRE
Aluminum is a stiffer wire and causes more wear and stress on the welding
unit’s wire feed mechanism. A spool gun is recommended when welding with
aluminum wire.
