How to Troubleshoot MIG Welder Problems

Although easier to learn than welding with an oxyacetylene torch, MIG welding still requires practice in order to perform it properly.

Metal inert gas (MIG) welding machines incorporate an automatic wire electrode feeding system, a torch head coolant system and an inert shield gas delivery system all through the same torch gun. Although MIG welders are easier to operate than oxyacetylene welding techniques, the complexity of the MIG setup creates more opportunity for mechanical problems. Working with electrical variables and the use of shielding gas also require practice to develop the necessary skills for a successful MIG weld. The following tips will aid you in perfecting your welding technique.

Things You'll Need

• Wire brush
• Grinder
• Steel wool

Instructions

Cleanliness

1. Clean your tools and the metals that you are welding in order to ensure your tools are in working order and your project welds properly. To clean your torch head, use a small wire brush to remove excess carbon buildup. Use a grinder, a wire brush or steel wool to remove any paint, dirt or oxidation from the metal that you are welding.

2. Use the proper shielding gas for your project to protect the weld from contamination. MIG welds require a cloud of inert gas to surround the weld site during the welding process to prevent oxygen from contaminating the weld bead. Steel requires a mixture of argon and carbon dioxide, whereas aluminum requires pure argon to shield the weld. Failure to use the proper shielding gas will cause pores to develop in your weld bead.

3. Weld your projects using pure metals. Contaminants, such as sulfur or phosphorous, contained within the metal itself can cause welds to fail. Therefore, choosing the higher quality metal for your project will reduce the chance of your joint failing.

Voltage and Amperage

1. Reduce the voltage of your MIG welder if you are experiencing difficult arc control, the weld is uneven, you are burning holes in your project metal or your weld seeps through the joint.

2. Increase the voltage of your MIG welder if you are having difficulty causing an arc to form, your joints are not connecting to the parent metal at the base of the joint, your weld bead is sunken or your weld is too shallow between adjoining plates.

3. Set the voltage of your MIG welder to the appropriate setting for the metal type and thickness of your project by referring to the MIG manufacturer's chart.

4. Decrease the amperage and feed speed of your MIG wire if your welds are too wide, you are burning holes in your metal or you are still having difficulty creating an arc at the proper voltage.

5. Increase the amperage and feed speed of your MIG wire if your joints are not connecting to the parent metal at the base of the joint or your weld bead is convex even though you have properly set the voltage.

Tips & Warnings

• Practicing your MIG welding with scrap metal on a wide variety of metals and joint types will help you develop better techniques.

• Always wear appropriate safety gear when welding.

• Always weld in a well-ventilated area.

• Do not weld while wearing loose flammable clothing or near combustible materials.

References

• Miller: Troubleshooting MIG Before and After You Weld
• Bernard: The Basics: MIG Troubleshooting
• Weldingspark: MIG (GMAW) Troubleshooting