Wire types and sizes - Use the correct wire type for the base metal being welded. Use stainless steel wire
for stainless steel, aluminium wires for aluminum and steel wires for steel.
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 you machine.
As a guide refer to the “Welding Wire Thickness Chart” below.
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 in the atmosphere, 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 ow smoothly.
The correct gas ow is also very important in protecting the welding zone from the atmosphere.
Too low ow will give inadequate coverage and result in weld defects and unstable arc conditions.
Too high ow can cause air to be drawn into the gas column and contaminate the weld zone.
Use the correct shielding gas. Co2 is good for steel and oers good penetration characteristics, the weld
prole is narrower and slightly more raised than the weld prole obtained from Argon Co2 mixed gas.
Argon Co2 mix gas oers better weld ability for thin metals and has a wider range of setting tolerance on
the machine. Argon 80% Co2 20% is a good all round mix suitable for most applications.
Argon Co2 Co2
Penetration Pattern for Steel
WELDING WIRE DIAMETER CHART
RECOMMENDED WIRE DIAMETERS
24 Gauge (.60mm)
22 Gauge (.75mm)
20 Gauge (.90mm)
18 Gauge (1.0mm)
16 Gauge (1.2mm)
14 Gauge (1.9mm)
0.118” / 3.0mm
0.196” / 5.0mm
0.236” / 6.0mm
0.314” / 8.0mm
0.393” / 10.mm
0.472” / 12.0mm
0.025” 0.030” 0.035” 0.040”
MIG SOLID WIRE GASLESS FLUX CORED WIRE
0.030” 0.035” 0.045”
For material thickness of 0.196” / 5.0mm and greater, multi-pass runs or a beveled
joint design may be required depending on the amperage capability of your machine.