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How To Fix An Erratic Arc: MIG Welding Troubleshooting

mig welding troubleshooting: arc

Your weld is going perfectly – until your arc starts to crackle, flare-up, or otherwise misbehave. An erratic arc is likely due to a wire-feeding problem or conductivity issue, but getting to the source can be time-consuming when you’re dealing with so many interconnected, intricate parts.

Use these tips to get back up and running, then follow our long-term maintenance advice for keeping your gun in optimal shape.

MIG Welding Troubleshooting 101: How to Fix an Erratic Arc


It’s recommended that you blow out and wipe down the drive wire feeder to remove dust and metal shavings.


Fine-Tune Your Drive Roll Tension

Set too little tension, and your wire could slip. Use too much and it could deform, pushing dust and metal shavings into the lines. But even though the MIG welder is a piece of precision equipment, finding that perfect tension balance can be a bit more of a trial-and-error process. Follow your manufacturer’s parameters as a good starting point.

Look Inside the Liner

Check for proper trim, unwanted kinks, or a buildup of gunk like lube, dirt, moisture, or dust. Any or all of these things could trip up the wire feed. Be sure that the liner coils are tightly wound and have good deflection and rigidity to withstand twisting. This is especially true with long cables.

Check Your Tip

Examine your contact tip for smooth and consistent inner diameters, and ensure that it’s the right size for the wire – when you’re dealing with precision machinery, even a 100th of an inch can cause trouble. Watch for a wandering wire or wear on the ID of the tip (called keyholing), and if it looks worn, toss it. A worn-out contact tip can also lead to conductivity issues.

RELATED: Causes of Contact Tip Burn Back

Bolster Your Ground

Before you even turn on your gun, make sure you have a good ground. It might be the most important success factor of all. Always try to attach your grounding clamps to your work instead of the table, because even if you lose contact for just a few seconds, your voltage will stop but your wire feed won’t.


While arc issues can be fixed in the moment, it’s better – and less expensive –  to avoid them altogether by keeping your machine in optimal shape.

Use a Good Wire

Use a welding wire that best suits your job, and ensure that it’s consistent throughout the entire length and across batches. If your wire looks good but still gives your problems, dig into its chemical composition or consider some testing with similar wires.

mig welding troubleshooting, remove the nozzle, tip and diffuser prior to blowing out the MIG liner Remember to remove the nozzle, tip, and diffuser before blowing out your MIG liner.

Love Your Liner

Extend the life of your line by blowing it out with compressed air to get rid of the dust and shavings every time you change the liner or the wire – if not more. Ideally, you should clean your liner weekly.

RELATED: How To Avoid Bird Nesting

Use the right parts

This doesn’t necessarily mean using the most premium products, but do use the products that were made for your job and meant to be used together. Find supplier partners who sell products based on best practices.

And remember that products that are cheaper, in the beginning, can end up costing a lot more in the long run.

Get The Right Parts from American Torch Tip

Looking for high-quality parts MIG torches and consumables? We are here to help!

We have an array of MIG welding equipment for all of your needs.

Download The Ultimate MIG Troubleshooting Guide as a quick reference in your production line.

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