What Causes Welding Spatter?

If you’ve seen welding being done in movies, you probably recognize it by the sparks and spatter flying all over the place. While it looks great on the screen, it is a nuisance in real life.

It creates more work because it requires cleaning, wastes material, and can severely burn if the right safety equipment is not being used.

It is almost impossible to reduce spatter, but we can definitely reduce it by understanding why it happens.

So what causes spatter? There are several causes, including technicalities such as contaminants on the surface, machine settings, and even the angle at which you’re working.

The main causes of welding spatter are:

  • Metal composition
  • Metal coating
  • Dirty metal
  • Low-grade filler
  • Contaminated filler
  • Welder settings
  • Welding technique
  • Welding gas

In this article, I’ll explain why each of these can have an impact on weld spatter so you can focus on reducing it in your welds.

What is spatter in welding?

But first, what is spatter? It’s a kind of welding defect. The name ‘spatter’ is given to the molten metal blobs that spat from your weld over your work or on you. The blobs are liquefied, so they stick to almost everything they land on. If they fall on your work, they can be a menace to clean up, and if they land on you, they’ll burn through your skin.

What causes welding spatter?

As mentioned earlier, there are several causes for spattering. Let’s look at each of them and their solutions.

Metal composition

The quality of the metal you weld has a significant impact on the amount of spatter produced. Some metals are not designed for welding and have different components added to them with varying strengths that lack weldability. Some are sold weldable metals but manufactured as inexpensively as possible. Cheap additives may be included in the manufacturing mixture. For reduced spatter, it is best not to use either one of these metals. Inexpensive metals may look appealing, but the contaminants and components they contain can cause a lot of excessive spatter.

Solution

Find the right metal to weld with. If these materials are all you have to get the job done, you may need to find other solutions.

Metal coating

With the right type of material, you can ensure minimal spatter, but sometimes a specific coat is needed to cover the metal before you weld. This could be galvanized coating, coatings of other metals such as zinc, chrome, rubber, paint, or anything else that covers the surface.

The purer the material being weld is, the cleaner the weld will be; in turn, there will be minimal spatter. Some coatings, such as pre-primed steel, are designed not to contain weld contaminants and will not cause spatter.

However, most of these coatings will make your life difficult.

Solution

Grind the coat off where you will be welding. The layer does melt away when you weld, but grinding it off before you start will give you a pure surface and produce much less spatter.

Make sure to grind off around the area you’re welding, or the heat will consume the nearby material and cause spatter anyway.

Dirty metal

Just like the components within a metal or the coating on the surface can cause issues for welders, dirty can be a contributor too. It could be oil, grease, marker lines, or even dust – none of those do well with welding and cause spatter.

Solution

Make sure to clean before you weld. Welding is straightforward, and if all the work is done before you start, it should produce minimal spatter.

Of course, cleaning is an important part of any job, and this does not exclude welding. It is not a lengthy process either – a quick wipe with a rag will suffice.

Low-grade filler

If you want to get rid of spatter, you would have to be willing to dig a bit into your pocket. Regardless of the discipline, the equipment you use needs to be of high quality and have the right composition for clean welding.

Like with parent materials, it is cheaper for corporations to create fillers with added components. Though they still serve their purpose, the extra spatter becomes a result of the compromise.

Solution

Make sure you look into the quality of the filler you are planning on using. Don’t buy the filler you find at the lowest price or the most expensive to get the best.

Look into the various types and what they have to offer so you can be sure you get a quality product that will produce the least spatter.

Contaminated filler

Often, welders leave their equipment around without covering them.

This can cause them to get contaminated with oil, dirt, dust, and even start rusting from lack of use. Dirt and rust entering the weld can cause spatter.

Solution

You should look after your consumables by keeping them covered when they aren’t in use. Stainless steel filler rods don’t rust, but if they are kept out, make sure you wipe them before you weld to get rid of dust.

However, steel dust can cause stainless rods to rust as well, so if you’re grinding steel, make sure to cover the stainless rods or keep them away.

Though most MIG spools are covered, the wire should always be kept in a bag unless it’s used frequently or the spool cover is sealed. Moisture building up on the coil if it’s left open too long can cause rusting.

Arc welding rods are less critical since the flux on the rod removes contaminants on its own, but wet or oily rods will produce more spatter. Therefore, to stay safe, it is best to keep them in a bag.

Welder settings

If the settings are out of whack, they will cause spatter. If the amperage is too high, it will cause spatter.

To fix it, you should either lower amperage by decreasing the wire speed or increase the voltage. Similarly, if the voltage is too low, it will cause spatter.

Electric Stick Out or ESO is the distance from the contact tip to the workpiece. If this is too high, it will increase spatter and also other problems like lack of penetration and porosity.

Solution

To determine what settings work best for your project, practice on a piece of clean scrap metal, and adjust the settings until they are refined.

Welding technique

This refers to the angle and speed at which you work. Regardless of whether you use the push or drag technique, the angle can make a difference.

Steep angles cause a lot of spatter, and some arc welding techniques cause a lot of spatter if you drag too fast. Additionally, when the wire feeder cannot feed wire at a steady speed, the fluctuation in amperage can cause spatter.

Solution

The optimal angle for welding is about 15 degrees, so you should keep your angle at 15 degrees. Sometimes there is no choice in which case you have to put up with some spatter.

Ensure your travel speed is correct. Don’t go too fast or too slow, and make sure you don’t have any feeding issues.

Welding gas

The type of gas you use can have an immense effect on how cleanly you weld. Argon and carbon dioxide are the most commonly used ones.

Carbon dioxide is less expensive, shields well, and helps with deep penetration; however, it causes more spatter. Argon is used to MIG weld aluminum and TIG weld stainless steel.

Steel welding using argon is of low quality and results in bad spatter.

Solution

Various mixes are good for different kinds of welding. Thicker steels require a higher percentage of carbon dioxide.

The right mix for your thickness will give you the smoothes weld with minimal spatter.

Related questions

How do I prevent spatter?

Besides the specific solutions mentioned for the causes above, you can use anti-spatter sprays that you can apply over your welding area.

Welding tape can also be applied anywhere that you want spatter-free though it cannot be used directly where you weld, like spray cans. Spatter chisels or grinders can also be used to chip or grind away spatter.

What are the other types of welding defects?

Welding defects besides spatter include incorrect profile, craters, cracks, incomplete filling, distortion, blowholes and surface, and internal porosity.

How to stop welding spatter from sticking?

You could use needle noses to clean out your nozzle, spray your nozzle with nonstick spray to reduce spatter sticking, or buy a commercial nonstick dip to prevent spatter from sticking.

About Pierre Young

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Hey, I'm Pierre Young a qualified AWS Certified Welder. I got into welding in 2009 as a side hustle. Ever since then, I've been doing all kinds of welds - both for business and pleasure. While immersing myself in this wonderful hobby, I've learned from hands-on experience what welding gear works and what doesn't. Welding Headquarters is the site where I share everything I've learned.

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