How To Reduce Excessive MIG Welding Spatter

MIG welding is one of the most straightforward and easy-to-use welding methods, popular among beginners, hobbyists, and DIY lovers. Why, you may ask?

Because it is fast and efficient and requires less skill to produce high-quality welds, however, sometimes welds don't turn out right.

One of the most common MIG welding defects is spatter, and it can even occur to seasoned welders. Although spatter isn't a structural defect that can produce failure, it can affect aesthetics and make post-weld cleanup harder.

That's why we'll thoroughly explain what it is, why it occurs, and how to reduce excessive MIG welding spatter.

MIG Welding Process

What Is MIG Welding Spatter?

Spatter is a surface welding defect in the form of tiny metal droplets or blobs. These droplets are nothing more than excessive molten MIG wire that spits around the weld joint and sticks onto the base metal, ergo name spatter.

Compared to defects such as cracking or undercutting, these droplets won't affect the structural integrity of the weld or cause weld failure. Spatter is a surface defect, which means it only occurs on the surface of the weld but primarily on the entire base metal piece.

Why is MIG Spatter Bad?

Since MIG weld spatter won't affect the integrity of the weld or cause failure, many welders wonder why it is bad. While wire welding processes such as MIG create some spatter, you want to avoid excessive spatter.

First of all, the spatter can affect the weld aesthetics. Seeing those tiny droplets around your welds doesn't feel right, especially in the applications that require the highest quality welds.

The bigger issue with the MIG welding spatter occurs once the molten droplets solidify and stick to the base metal. Removing the excessive spatter can be challenging and time-consuming. The hardest spatter sometimes requires mechanical methods, such as chiseling and grinding.

Source: https://americantorchtip.com/blog/5-tips-to-reduce-excess-mig-spatter/

While in hobby MIG welding, removing the spatter won't typically take too much, it can be inefficient in industrial applications. Spending time in post-weld cleaning creates downtime or even requires a complete rework. The downtime and rework increase the all-around welding costs, so reducing excessive MIG welding spatter is crucial.

How To Reduce Spatter When MIG Welding

As noted, MIG welding will create some spatter regardless of the precautions or skill of the welder. But, excessive spatter can make you throw away the piece, so you will want to avoid it, or at least reduce the amount of spatter.

To reduce the excessive MIG welding spatter, you must first understand why it occurs in the first place. The leading causes of spatter in MIG welding are:

• Incorrect welding parameters
• Dirty metal surface
• Incorrect welding technique
• Low-quality consumalbes
• Shielding gas

Incorrect MIG Welding Parameters and Spatter

Incorrect MIG welding parameters such as wire feed speed (or amperage) and voltage can cause a spatter. For example, your wire will be too hot if the amperage is too high. Besides burning through the pieces, the high WFS and voltage will cause the wire to spit around the weld and base metal. Although high voltage and amperage boost productivity and increase the welding speed, you will get into a globular transfer, known for high spatter.

The incorrect polarity in MIG welding will also cause a spatter. MIG welding uses a DCEP (Direct Current Electrode Positive) polarity. Meanwhile, DCEN will cause extremely inconsistent arc and excessive spatter you want to avoid.

Lastly, while it is not a typical MIG welding parameter, incorrect wire stickout can cause a spatter. Too long a MIG wire stickout can dig into the weld and cause a spatter. Conversely, too-short wire stickout can generate an erratic arc which creates a spatter.

How to Deal With Parameters And Avoid Spatter

The first step in troubleshooting the MIG welding spatter is getting the parameters right. That means you should find a sweet spot between the wire feed speed and voltage to get enough penetration, stable arc, and consistent results.

To do so, you should always follow the manufacturer's recommendations for the given material type and thickness. If you still have spatter issues, try decreasing the amperage and increasing the voltage. If you are an absolute beginner, you should look for a machine with Smart MIG or Synergic MIG options, such as YesWelder Firstess DP200.

YesWelder Firstess DP200 Multi-Process MIG Welding

This MIG welder automatically adjusts the wire feed speed and voltage to metal thickness, wire diameter, type, and shielding gas type, creating a great headstart. You can tune these parameters to get even less spatter as you develop your skills and preferences.

Also, make sure you check the MIG welding polarity before welding. MIG welding is DCEP, which means your torch should be in the positive (+) terminal on the welder and ground on the negative (-) side of the terminal.

Finally, you should maintain a 1/4 to 3/8" MIG wire stickout. You don't want your wire to spit around or clog the nozzle because of the stickout length.

Dirt and Spatter in MIG Welding

Another leading cause of spatter in MIG welding is dirt. Moderate dirt on the surface, wire, or liner can cause a spatter. Surface contamination such as dirt, oil, grease, paint, or rust, can highly affect the welding performance and metal weldability. Impaired weldability can lead to dozens of weld defects, including a spatter.

For example, MIG welding through dirt, oil, paint, or rust will cause them to boil, increasing the overall temperature. The wire and contaminants can spit across the weld joint, creating spatter, porosity, or burning your skin.

Similar issues follow the MIG welding wire or liner. Dirty wire or liner can also affect the welding performance and impair the composition of the wire. Once again, the dirt can cause various defects, including the spatter.

Finally, you should be cautious when welding metals with a protective surface layer. Those layers, such as zinc in galvanized steel or aluminum oxide in aluminum, improve the properties of the metal or give it corrosion resistance. However, they can affect the metal's weldability, creating excessive spatter, burn through or unpredictable results.

How to Solve MIG Spatter and Dirt

To reduce the MIG welding spatter, clean the surfaces before welding and make sure your consumables are clean. The rule of thumb in welding is the more time you spend cleaning the surface before welding, the less time you'll spend post-weld cleaning.

Unlike Stick welding or Flux-cored arc welding, MIG is not known for its performance on dirty surfaces. So, use an old rag or wire brush to remove light contamination, such as dirt, oil, or grease. For thicker contamination, use aggressive solutions or a grinder to penetrate the deeper layers of contamination.

When storing your consumables, such as liner or MIG wire, ensure they are away from dust, metallic particles, or dirt in your garage or shop. As noted, dirty wire or liner can cause a spatter. So, if you are not using the wire, store it in a clean place.

Finally, be careful when welding the metal with the protective surface layer. You will want to remove the surface layer before welding to avoid health issues, welding performance, and spatter.

Improper Welding Technique and MIG Spatter

Although MIG welding is forgiving and beginner-friendly, you will still need a proper welding technique to produce sound welds and satisfying results. That means your welds are spatter-free, but to get there, you must master the torch movement, angle, and speed.

The travel angle is the angle at which the MIG gun is tilted as you weld. The incorrect travel angle in MIG can cause several defects, such as undercutting, lack of fusion, and spatter. The incorrect travel angle focuses the heat into one side of the joint, causing overheating and molten metal spitting.

Incorrect travel speed can also cause severe weld defects such as lack of fusion, burn-through, or spatter. If you move too fast, you'll just run over the joint, without allowing the wire to penetrate the joint. Meanwhile, moving too slowly focuses the heat into the joint, creating the spatter.

How to Practice MIG Technique to Reduce Spatter

Understanding the foundations of the MIG welding technique is crucial in achieving the highest-quality, spatter-free welds. Regarding travel angle, you should always angle the MIG gun between 5° to 15°. The working angle depends on the joint design you are using. For a butt joint, 90 degrees is ideal, while you'll need a 45-degree angle in fillet joints.

The travel speed should be consistent through the MIG weld. When troubleshooting the MIG spatter, try increasing the travel speed. But to the point where you get enough penetration and good weld tie-in.

The final concern of the welding technique is whether you push or pull when MIG welding . Regarding MIG welding, pushing or pulling is a matter of personal preference, but most welders prefer to drag or pull. Pulling allows you to see and control the weld puddle, which can also help you reduce the weld spatter. For start, you should use the straight or stringer beads with MIG welding. Side-to-side motion can cause more spatter and other defects if you are inexperienced.

Low-quality Consumables and Spatter

MIG welding uses several consumable pieces such as MIG wire, nozzle, liner, contact tips, etc. Using the correct, high-quality consumables is crucial in achieving the strongest MIG welds and avoiding spatter.

The quality of MIG wire can directly impact the overall quality of the weld. Although the wire composition is dictated by strict AWS standards, the quality can depend on the manufacturer. Cheap, low-quality wires can have unpredictable amounts of alloying elements or an inconsistent diameter through the spool. These issues can cause feeding problems, inconsistent arc, and spatter.

Other MIG gun consumables, such as nozzles, contact tips, liners, or diffusers can also cause feeding and spatter issues. So make sure you buy from trusted suppliers such as YesWelder Accessories and torch consumables .

24KD Binzel MIG Welding Gun Consumables

Choosing the Right Consumables to Avoid MIG Spatter

To avoid excessive spatter with MIG welding, buy your consumables from a trusted supplier, and make sure they are suitable for your machine and project. As noted, we strongly recommend checking out the YesWelder accessories and consumables, as all of them are quality-tested and built according to rigorous AWS standards. Only then you can be sure your consumables are not causing the MIG spatter.

In addition, ensure your consumable sizes and types are suitable for the metal and project you are welding. For example, use ER70S-6 when MIG welding steel, or ER4043 when welding aluminum. Matching the composition of the wire and base metal is crucial in avoiding the spatter. The same rules apply for diameter. So, use .023" wire on thin pieces and .030" on medium thickness. Choosing an inappropriate diameter can also cause a spatter.

YesWelder ER70S-6/10LB-0.8 .030" 10LB Spool Carbon Steel Solid MIG Welding Wire

Follow the same pattern when buying other consumables. Ensure the nozzle or contact tip is suitable for your MIG torch. If everything is well synergized, you are less likely to encounter spatter in your MIG welds.

Shielding Gas And Spatter

MIG welding is highly versatile regarding the shielding gas choice, primarily because of the use of CO2. Carbon dioxide is a semi-reactive gas that shows excellent results in MIG welding, and many welders prefer it due to its low price. Some welders even prefer using a pure CO2 shielding gas, leading to a process known as MAG (Metal Active Gas) welding.

CO2 brings various advantages to MIG welding. This shielding gas stabilizes the arc and increases the penetration that Argon lacks. That's why the most preferred shielding gas for MIG welding is a mixture of 75% Argon and 25% CO2.

75% Argon and 25% Carbon Dioxide Mixture Shielding Gas
Photo by @stevensullivan47

However, higher concentrations of CO2 in MIG welding create a semi-reactive protective atmosphere. It also produces high heat and penetration, which results in worse weld aesthetics and, you guessed it, excessive spatter. In some MIG welding applications, even if you get all the aspects right, reactive or semi-reactive gases can cause a spatter.

How To Deal With MIG Spatter Caused By Shielding Gas

The solution to MIG spatter caused by shielding gas is rather simple. You should avoid using higher concentrations of CO2, or any reactive gasses. For oxygen or nitrogen, welders do not recommend more than 5% of the entire shielding gas mix, while the optimal range of CO2 is up to 25%.

By adding a small portion of reactive or semi-reactive gasses, you deal with issues of Argon as the primary shielding choice. At the same time, you limit the drawbacks of reactivity you are trying to avoid in the first place. While pure CO2 is an economical choice for quick and cheap MIG welds on mild steel, remember that it can cause lots of excessive spatter.

Additionally, you should check the shielding gas supply, including the containers, lines, and fittings. Loose fittings or old gas cylinders can open the door to contamination, which can affect the shielding properties of the gas, and create porosity or spatter.

Quick Tips On How To Reduce Excessive Spatter In MIG Welding

• Adjust welding parameters: Check the wire feed speed (amperage) and voltage. Troubleshoot the issues by reducing the amperage and increasing the voltage.
• Check the polarity: MIG welding uses the DCEP, or reverse polarity, so ensure your torch and ground are correctly set up.
• Adjust wire stickout: Normal stickout is usually around 3/8 inch, and too long or short can cause a spatter.

• Clean surfaces before welding: Surface contamination such as dirt, oil, rust, or paint can cause spatter. So, clean the surfaces and prepare the pieces before welding, to reduce the time spent cleaning after the welding.
• Use clean and high-quality consumables: Buy consumables from a trusted supplier, and make sure they match the machine or MIG gun you are using. Wires should be clean, with proper diameter and composition for the welding project.
• Practice welding technique: Use a 5 to 15-degree travel angle, proper working angle, and moderate welding speed. Many welders prefer pulling to control the weld puddle and avoid spatter.

• Use the correct shielding gas: Reactive and semi-reactive gases can create a reactive atmosphere, increase heat, and cause a spatter. C25 mixture of 75% Argon and 25% CO2 works well in most MIG welding on mild steel.

Final Thoughts

Although MIG welding spatter is not a structural defect, meaning it won't affect the integrity of the weld, it can highly impact the overall appearance and aesthetics. Excessive, hard spatter can be challenging to remove and time-consuming, sometimes requiring a complete rework.

While MIG welding does produce some amounts of spatter, there are ways to reduce it and create spatter-free welds. Understanding the leading causes is crucial in troubleshooting. Technique, parameters, and inadequate or dirty welding equipment can all cause spatter, so checking each aspect can make your everyday welding much faster and better looking.