4 Reasons Why Your MIG Welder Is Sputtering

Welding can be an intricate and complicated process, but if you find that your MIG welder is sputtering, it will undoubtedly make this process more difficult than necessary. Fortunately, there are many common reasons why your MIG welder might be sputtering, and they are all simple fixes. 

The top four reasons your MIG welder might be sputtering are excessive resistance/poor conductivity, dirty wires or welder components, low gas flow, and worn contact tips and liners. When troubleshooting your sputtering MIG welder, be sure to check if one of these complications is the cause. 

One way to ensure that your MIG welder doesn’t sputter is to take necessary precautions regarding equipment maintenance and thorough checks of your station and materials before welding. Read on to learn more about how to troubleshoot and prevent this common welding issue.

Top 4 Reasons Your MIG Welder Might Be Sputtering

There are various reasons your MIG welder might be sputtering, but these are the top four. Therefore, they are a great place to start when you are trying to locate the cause of the issue to remedy it. 

  1. Excessive Resistance/Poor Conductivity Along the Circuit

If you notice that your MIG welder is sputtering or creating an erratic arc, there’s a chance that this is caused by excessive resistance or poor conductivity along the circuit. 

Excessive circuit resistance will significantly impact the welding arc because it reduces the amount of current that will flow through the MIG welder gun to the arc. In order to overcome the restricted current flow, the MIG welder’s power source will send a voltage surge after it senses a significant reduction in current flow to the arc in attempts to overcome the issue. 

As a result of the increased voltage during this process, the MIG welder typically starts popping and sputtering, affecting the arc and overall welding quality. 

A series of mechanical factors could also decrease conductivity, such as damaged copper stranding within the cables, a diffuser that is too small for the application, or a worn contact tip.

  1. Dirty Wire or Components

Clean components and wire are essential to smooth, efficient welding. Checking your welding materials and components should be one of the first steps you take before you begin the welding process. 

Common substances that could potentially cover your wire, metal, or MIG welder components include rust, paint, dust, grease, and more. If these contaminants are present during welding, they will likely burn, bubble, or outgas due to the high temperatures necessary for the welding process. 

Not only will this likely cause your MIG welder to sputter, but it could also damage the welder gun and its components, requiring future maintenance or replacement. Additionally, all foreign contaminants will mix in with the puddle and create a weak joint that will ultimately fail. 

Therefore, it is essential to ensure all of your equipment and materials are clean and shiny to prevent damages and insufficient joints. 

  1. Low Gas Flow

Another common cause of sputtering in MIG welders is low gas flow. Without proper gas flow, you cannot hope to perform a quality weld that will hold. Shielding gas protects the liquefied weld puddle from contaminants, both physical and atmospheric. Without this protection, pinhole imperfections, or porosity, will occur in the weld and cause the MIG welder to sputter.

Some telltale signs that your system might be experiencing low gas flow, or even the wrong gas type, would be a charred or sugar covered weld face, surface porosity, or a pinhole leak in the gas line. 

Having a proper gas flow can be tricky with welding. If the flow is too low, you will have sputtering of the MIG welder, but if it is too high, you will experience spattering, which is a messy, but common welding issue. Be sure to have the appropriate shielding gas and flow rate before you begin to prevent these issues.  

  1. Worn Contact Tips and Liners

As is the case with most forms of equipment, if components of your MIG welder are worn, they will likely cause sputtering during your weld. Two of the most common pieces that are prone to wearing down are the contact tips and liners. 

The contact tip is essential to transferring the welding current to the wire. As the wire passes through the bore, it should create that perfect arc necessary for quality welding. Therefore, if the contact tip is worn, this arc will be erratic or cause sputtering.

Liners are another vital component of MIG welding because they help guide the wire from the wire feeder to the contact tip. If the liners on your MIG welder are worn, they will compromise the entire gun by either obstructing the wire’s ability to reach the contact tip undisturbed or causing the MIG welder to sputter and produce a poor arc.

How Do I Stop My MIG Welder from Sputtering?

The best way to stop your MIG welder from sputtering would be to troubleshoot the four common causes mentioned above and see if this remedies the issue. Prevention is also an important measure to take to ensure your MIG welder functions properly every time. 

Troubleshooting the Top 4 Reasons a MIG Welder Is Sputtering

IssueCommon Resolutions
Excessive resistance/poor conductivity along the circuitCheck the three main connections -at the power source and the gun’s power cable plug-at the gun’s power cable, neck, diffuser, contact tip, and welding wire-at the work lead, welding table, and power source. Remove or replace any damaged materials in the gun or wiring.Consider using compression fittings.
Dirty Wire or ComponentsCheck and clean the components of your MIG welder gun to remove any potential contaminants.Dispose of any compromised wire.If welding on metal, be sure it is clean and shining. A chemical cleaner that removes oxidation is typically helpful here.
Low Gas FlowCheck your flow gauge regulator to determine your gas flow and how it should be altered.Make sure the orifice in the outlet fitting isn’t plugged.Determine if there are any leaks in the pipe joints, diaphragm vents, or welder gas connection.
Worn Contact Tips and LinersLiners tend to be one of the cheapest components of the MIG welding process, so it is best to replace them when you notice they are worn.When there is evident erosion in the contact tip bore, it is time to replace it. If it isn’t, not only will sputtering continue, but other issues including wire placement offset, erratic arc, and irregular or missed welds.

MIG Welder Sputtering Prevention Through Maintenance

Sputtering can be caused by an array of issues not mentioned in this article. Therefore, it can be tricky to pinpoint what is causing your MIG welder to sputter and how to remedy the issue. The best way to ensure these steps never have to occur is to conduct regular maintenance of your MIG welder and its materials. Here are a series of common maintenance steps:

Maintenance Tips

  • Turn off and unplug your MIG welder daily to prevent unnecessary from voltage moving through the plug.
  • Keep your MIG welder covered when not in use to protect it from dust and other contaminants.
  • Turn off the gas to the machine and purge the line to remove all gas from the system.
  • Always wrap your gun, but loosely. A taught gun will result in kinking of the gun liner.
  • Tighten your ground clamp at least once a month.
  • Every three months, check and potentially repair or replace your weld cables as well as the gas hose fittings. This is also the time frame to clean and tighten weld terminals as well as compressing air through the lines to remove any potential debris.
  • Clean your welder with compressed air every six months to remove debris.
  • You should also remove and clean drive rolls and replace consumables (ex. nozzles, tips, diffusers, liners) around the 6-month mark as well.

Final Thoughts

If you experience sputtering with your MIG welder, don’t be discouraged. This is a common issue that can be tricky to pinpoint the cause, but it is usually an easy fix once it is found. The four common reasons mentioned in this article are an easy place to start when troubleshooting.

Remember, although sputtering is a common issue, it typically means that something in your MIG welder, or materials, is either damaged or functioning improperly. It is not recommended to work through a sputtering welder. Not only will this cause further damage, but it will produce an erratic arc and weak joints. Consistent maintenance of your MIG welder will significantly reduce the possibility of sputtering and ensure a smooth welding experience. 

Alexander Berk

A bit about myself: I am a certified international welding engineer (IWE) who worked in different welding projects for TIG, MIG, MAG, and Resistance Spot welding. Most recently as a Process Engineer for Laser and TIG welding processes. To address some of the questions I frequently got asked or was wondering myself during my job, I started this blog. It has become a bit of a pet project, as I want to learn more about the details about welding. I sincerely hope it will help you to improve your welding results as much as it did improve mine.

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