How to Understand a MIG Welder

MIG welding is the preferred method of joining metals together permanently. It's convenient for persons who like to work on their own cars in their garage. Nevertheless, you need to understand how your MIG welder works in order to achieve the best results.

Difficulty: Moderately Challenging

Instructions

1. Expect to find a reel of steel wire inside the machine. A series of rollers pushes the wire out and feeds it to the torch. You can now start an arc between a continuously fed filler metal electrode, or wire, and the work piece.

2. Set the wire speed to the maximum that you will likely use. Press the trigger on the torch. Letting go of the trigger should cause the wire to stop without unraveling.

3. Consider the fact that the gas used in MIG welding goes into the machine and up to the torch. Generally, this mixture consists of 75 percent argon and 25 percent carbon dioxide. The gas produces a protective shield around the electric arc, or weld, and protects it from outside contaminants, which can cause oxidation. Examples of other shielding gases are pure argon, argon-oxygen, argon-helium and carbon dioxide. Carbon dioxide produces the best results because you get the best penetration.

4. Press the trigger on the torch when you're ready to weld; gas is released and a clean weld is produced. A pressure-reducing regulator on the gas cylinder controls the flow of gas. Factors controlling the flow rate are the design of the weld joint and the thickness of the material.

Tips & Warnings

• You need to change the gas depending on the metal you're welding. For example, for stainless steel you would use an argon-helium mix. Aluminum requires 100 percent argon, and you can use argon-carbon when welding carbon steel.

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