How To Operate a MIG Wire Welder

Using a MIG welder.

MIG welding, also known as GMAW, is a type of arc welding. MIG stands for metal inert gas, while GMAW stands for gas metal arc welding. MIG welders use a special wire as a continuous electrode, and a gas (generally carbon dioxide or argon, or a combination) to shield the arc from the atmosphere. MIG welders may also be used without the shielding gas by employing a flux core electrode wire.

The MIG welder has a control panel with an on/off switch, a voltage control and a wire speed control. A gas cylinder feeds the shielding gas to the welder. A gun and cable assembly supplies the gas and wire to the weld, and a ground cable and clamp are attached to the work to complete the electrical circuit.

Things You'll Need

• Wire brush
• Welding helmet
• Gloves
• MIG welder

Instructions

1. Clean the material to be welded with a wire brush.

2. Attach the ground clamp to your work piece. The ground clamp must be attached to clean bare metal; avoid rusty or painted surfaces. Inadequate grounding is the number one cause of poor quality welds.

3. Adjust the welder voltage and wire feed speed to match the metal you are welding, referring to the chart on the side of the welder. If you are joining materials of differing thickness, use settings appropriate to the thinner material.

4. Open the valve on the gas cylinder and adjust the gas pressure by turning the regulator knob. The proper gas pressure will vary, but 15 psi is a good place to start.

5. Put on the gloves and welding helmet and turn on the welder's main power switch.

6. Begin welding. Hold the gun at a 15 to 30 degree angle to your work, and about 3/8 inch from the surface of your work. Pull the trigger and move the gun as you weld. You may either push or pull the gun. A "sizzling" sound, like that of frying bacon, indicates that your power level and wire feed speed are correct.

Tips & Warnings

• If you are working outdoors in the wind, the shielding gas may blow away. Consider using flux core wire on windy days.

• If you have a pacemaker, consult your physician before operating an arc welder.

• Never weld without your welding helmet in place.

• Don't weld near explosive fumes or gases.

References

• Miller Welds: Guidelines for Gas Metal Arc Welding (GMAW)
• Lincoln Electric: Weld-Pak 155