What Causes Weld Spatter? And Tips On How To Reduce It

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For serious welders, like those of you reading this article, spatter might as well be a four-letter word. There is nothing good about it. So, it is fair to wonder:

What is weld spatter, how is it caused, and how can it be prevented?

Weld spatter is an all-too-common occurrence in the world of welding, often leading to unsightly results and potential safety hazards.

As a welder, understanding the root causes and best practices to minimize this pesky problem is crucial for producing high-quality, visually appealing welds.

In this article, we delve into the intricacies of weld spatter, its various causes, and how to effectively address each of these issues. We also discuss the importance of proper equipment maintenance, welding techniques, and safety precautions to ensure both a spatter-free welding experience and a pristine final product.

What is Spatter?

weld defect spatter

Spatter, that pesky welding phenomenon, refers to the small, molten droplets that scatter during the welding process, often settling on the surrounding work area, base material, or your welding tools

These tiny globules of metal, once cooled, can leave behind unsightly imperfections or even pose safety hazards due to their potential to cause burns.

If it lands on you, that means your flesh is about to let you know just how hot these pesky spheres are. They can burn through clothing and scorch your skin.


spatter through clothing
Weld spatter burning straight through clothing. Wear protection!

Most weld spatter problems occur when MIG welding. Although it is also a problem for flux-cored and stick welding.

Since you ejected some metal from the weld as spatter, in severe cases, the integrity of the weld might be questioned.

So, spatter may not be a four-letter word, but it does have the power to induce a steady stream of them from a welder.

And although spatter may seem like an unavoidable aspect of welding, understanding its causes and implementing effective techniques can significantly reduce its occurrence.

Is Weld Spatter Considered a Defect

While minor amounts of weld spatter are often seen as an inevitable part of the welding process, excessive spatter can indeed be considered a defect in certain situations.

The classification of weld spatter as a defect depends on the project specifications or relevant welding standards, which may have strict requirements for surface quality and finish.

When weld spatter exceeds the allowed limits set by these specifications or standards, it can compromise the integrity and appearance of the final product.

So, it’s crucial for welders to be aware of the project requirements and take necessary measures to minimize spatter during the welding process, ensuring that the final product meets the desired quality standards.

What Causes Weld Spatter?

The main reason for weld spatter is the instability of the welding arc, which can be attributed to various factors.

These factors include improper voltage and amperage settings, incorrect welding gas selection, disturbance in the weld pool during wire transfer, and the use of low-quality welding wire or base material.

For instance, when the voltage is too low or the amperage is too high for a specific wire and gas combination, the arc becomes too cool to keep the wire and pool molten, causing a stubbing effect that leads to spatter.

Furthermore, welding gases like CO2, while cost-effective, can increase arc energy and generate more spatter compared to Argon, which is often used to counterbalance the spatter caused by CO2.

Other factors that can cause spatter include metal composition, contaminated metals and your welding technique.

5 Tips To Prevent Spatter

Let’s take a look at each of the factors to you reduce weld spatter.

1. Using The Right Welder Settings

It is easy to use rules of thumb for welder settings, but they can become a crutch. Every weld has optimal settings, and your equipment should be adjusted for the specific weld you are doing.

If the “heat” and penetration are not right, you risk disrupting the welding pool and increasing spatter.

With a MIG welder, you must also get the wire feed correct. Too fast and you send solid metal wire into the pool, which causes a disturbance more than adequate to create spatter. Too slow, and you vaporize the wire before it gets to the weld. Again, more spatter.

Also, using the wrong polarity can cause excessive spatter. Forgetting to flip it back for solid wire after using flux-cored happens to everyone once in a while.

Another “setting” connected to how to reduce spatter with your MIG welder is the gas.

If the flow rate, the gas blanket, or the type of gas are wrong, it can impact how much spatter results.

How to Prevent Setting Related Problems

To address how to reduce spatter when MIG welding or using a stick, discussing MIG and stick welders separately is helpful.

MIG Welder Settings

Once in a while, you start a bead and see as much metal fly off as it lays down in the weld. Check your polarity. You probably forgot to flip from flux-cored wire to solid.  

Also, the current and/or voltage must be correct to achieve good penetration and proper heat. These settings work hand in hand with the correct wire speed.

If you feed wire too slowly, the wire melts too far from the metal, and it liquefies in the air instead of laying down in the bead. The result is spraying the molten filler outside of the weld, creating weld spatter. If this happens too close to your gun tip, you can even clog it.

Feed the wire too fast, and you send solid wire “poking” into the molten pool. This disrupts the melted metal and one of the results is welding spatter.

Related read: MIG Welding Settings Explained with Chart

The stick out from the nozzle must also be set correctly. A rule of thumb often stated is ⅜ inch. But it can vary based on the geometry of the weld. But too much stick out will result in more spatter, as well as several other problems with the weld.

Then, you must also make sure you have a good gas blanket evenly distributed while welding. Get the MIG gas flow rate wrong or apply a turbulent blanket of gas, and air will contaminate and affect your weld. One of the results is more spatter.

Stick Welder Settings

Your speed is linked to the current and/or voltage settings. Too hot, and you must move fast. If you recall, one of the causes of weld spatter with a stick is moving too quickly.

On the flip side, too cold, and your welding is rough. It fluctuates between welding and sticking, which causes spatter and an unsightly weld. 

Special Note on Welder Settings

To dial your settings, it might take some experimentation. Practice on scrap pieces of metal and slowly dial in the settings. If you make big changes, you risk jumping over the sweet spot.

Yes, this takes some time, but it also improves your welds and reduces the amount of spatter.

2. Clean Dirt and Contamination

Have you ever seen what happens if you add water to hot oil? It causes the oil to spit and splatter everywhere.

Think of dirt and contamination in the same way as water getting into hot oil. It will cause the molten metal to spit and splatter, causing spatter that you have to clean.

Also, you need to consider oil and other protective coatings or material applied to the metal by the manufacturer as contamination. Sure, you can weld through most of these surface treatments, but you will be cleaning up more spatter if you do.

Cleanliness is needed with your filler material, too. It is easy to ignore the dirt and oil that can get on welding wire or rods stored in a shop. Plus, they can rust over time. But dirty, rust or contaminated filler materials can cause spatter, too.

How to Prevent Dirt and Contamination Related Issues

If dirt and contamination cause spatter, eliminate it like the Terminator searching for Sarah Conner. Only you don’t have to rip pages out of the phonebook first. 

All kidding aside, dirt and contamination are the enemies, and you need to clean meticulously as part of your weld prep.

Dirt, oil, and rust should be removed on ¾ of an inch on each side of the weld. Grind, wire brush, or use a flap wheel if necessary. Bright metal is usually best.

Plus, remember your filler material needs to be clean, too. Be sure to store it in your shop undercover and in a cool, dry place. You do not want dirt, dust, oil, etc. to settle on it, nor do you want it to rust.

3. Use the Correct Filler Composition

Some metal is better than others. Cheaper metal often contains a lot of “filler” to keep the cost down. But the materials used as fillers in the cheaper alloys often make the metal unweldable. If you try, spatter will be inevitable.

The same is true for your filler materials. The cheaper rods and welding wire also can include materials that make the filler material prone to spatter. 

How to Prevent Material Composition Related Spatter

So, if a low-quality metal and filler can create weld spatter, do quality materials reduce spatter? As it turns out, yes.

It should go without saying, you need to know and understand the metal you are welding. If it is a quality material suitable for welding, spatter will be less.

This is also true for your filler. Do your research and understand what you are buying. You should get the best filler wire and rods you can find. The quality of your weld depends on it, and this will also help to reduce spatter.

4. Use the Proper Welding Technique

So you did meticulous prep, the metal is shiny clean, and you used the best, clean filler material you can find. Plus, you have your equipment settings dialed to the perfect settings for the weld you are about to make.

But that is not enough. Your technique can also create excess spatter. For example, the angle of the MIG gun can create spatter. Drift over a 15° angle, and the amount of spatter starts to increase. 

The same is true if you are stick welding; your technique matters. For instance, let your arc length get too long, and the amount of spatter increases. 

Also, the speed at which you move with both types of welders can increase the amount of spatter. If you move too fast or slow, it creates more spatter.

The “proper” technique has become the correct way for a reason. It produces the strongest, cleanest-looking welds based on years of experience.

How to Prevent Technique Related Issues

Welding is an art in that it relies on the user’s technique to achieve a good-looking, quality weld. Good technique is also key to keeping the weld spatter to a minimum.

Mig Welder

You need to get the direction you move while welding right. If you need high, consistent heat, pulling your weld is better. When you need heat distribution, pushing is more appropriate. This varies depending on the material being welded, but get it wrong, and you get more spatter.

push vs pull mig welding

Read more: Is it better to push or pull when MIG welding?

The angle of the gun must be about 15° to 20°. Get steeper, you guessed it, more MIG welding spatter.

Also, move at a proper speed. Moving too fast or too slow impacts the quality of the bead. But in many cases, it will also create more spatter.

Stick Welder

Same as with MIG welding, you cannot move too fast. It will create more spatter. One of the reasons for moving too fast is that the current and/or voltage may be set too high.

Another thing to make sure you get right, the arc length. In general, keep the arc length equal to the metallic core of the electrode you are using for the stick weld.

5. Use The Right Shielding Gas For MIG Welding

Another crucial factor influencing weld spatter is the choice of shielding gas used during the welding process.

The shielding gas serves to protect the weld from contamination, and its composition can significantly affect the amount of spatter produced. Some gases are more prone to generating spatter than others.

For instance, carbon dioxide (CO2) is a cost-effective shielding gas that increases arc energy but also tends to create more spatter. On the other hand, argon is often used to counterbalance the spatter-inducing effects of CO2.

A mixture of argon and CO2 is commonly used in MIG/MAG welding, as it offers a balance between cost and spatter reduction. The right blend of gases can help achieve a smoother and cleaner weld with less spatter.

Related read: Choosing the right gas for MIG welding

It is essential to experiment with various gas mixtures and flow rates to find the optimal combination for your specific welding application. Remember that factors like material type, thickness, and welding position may require adjustments to the shielding gas mixture and flow rate to reduce spatter and achieve the desired weld quality.

How to Clean Spatter

After taking all the precautions you can, you may still get some spatter at times.

When spatter occurs, you usually need to clean it to make the weld look its best. 

The bad news is the job is tedious. But the good news is you do have some options. Such as:


grinding weld spatter e1602161141130

One method of cleaning spatter is breaking out the tried and true angle grinder. It works but takes time and effort.

However, if you are grinding as part of the finishing operation, hitting the spatter at the same time makes sense.

Spatter Chisel or Hammer

chipping hammer e1602165161949

For those times when you get a small amount of spatter, a chipping hammer (like this one) works well.

These hammers are designed and manufactured in such a manner that it removes the offending spatter quickly without damaging the base metal, leaving you with a cleaner looking weld.

Sprays, Gels, and Tapes

anti spatter spray e1602160925752

Another strategy you can employ, don’t let the pesky little blobs stick in the first place. You can apply anti spatter spray and gel which are designed to keep spatter from adhering. 

Some welders also find tape works well, too, to mask certain areas. But use aluminum tape. It holds up to the heat of the spatter and does not melt like plastic tapes.

Wrapping It Up

In conclusion, weld spatter may be an unwelcome guest in the world of welding, but with the right knowledge and techniques, its impact can be minimized.

By understanding the various causes of spatter and implementing effective strategies such as optimizing welder settings, maintaining cleanliness, using quality materials, perfecting your technique, and choosing the appropriate shielding gas, you can significantly reduce spatter and produce top-notch welds.

Remember that practice makes perfect, and the more experience you gain, the better equipped you’ll be to address spatter-related issues. Don’t shy away from experimenting with different settings, materials, and techniques to find the perfect balance for your specific welding needs.

With persistence, attention to detail, and a commitment to continuous improvement, you’ll be well on your way to mastering the art of spatter-free welding and achieving exceptional results.

Keep the sparks flying, and happy welding!

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About Jeff Grill

Jeff Grill hails from Long Island, a 118 mile stretch of land that starts just off the coast of Manhattan and stretches deep into the Atlantic ocean. He has always been interested in welding from an early age and has the cuts and bruises to prove it as he set out to work with a variety of metals.

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