Spatter In Welding: What Causes It & How To Reduce Effectively?
You’re probably looking at spatters on your weld project and wondering what causes them to form and how you can avoid/prevent them.
Essentially balls of molten material formed by welding beads flying off and scattering, spatter in welding happens all the time—whether you’re a noob or experienced welder.
It makes your welds look messy and can be challenging to remove. In worst cases, spatter can burn through your clothing and dig a hole right into your skin!
After doing our own research, we have put together this in-depth guide to teach you everything you need to know about spattering.
You’ll discover what spatter is, what causes it, the effect it has on your project, and how you can achieve the smoothest welds with minimal spatter.
What is weld spatter? Is it a defect?
A spatter in welding is blobs, globules, or balls formed when the molten metal particles jump from your welding pool and fall into other surfaces of the plate you’re working on.
A spatter is formed when a welding droplet or bead scatters into smaller droplets (the spatters) near your weld.
The hot bits of molten metal or non-metal substance can also fall on your workbench, on the nearby welding gear, on the floor, or on your skin if you don’t have the right protection gear on when welding.
Keeping in mind that these tiny balls fly hot and in molten form, they tend to firmly stick on the surface they land on.
You can easily spot them because they usually form in a round, ball-like substance when they finally solidify and stick on whatever surface they fall on.
There are mixed opinions on whether a spatter is a welding defect. AWS lists this problem as a defect on their website and most folks base their argument on this listing.
From our findings, however, we can tell you that spatter isn’t a serious defect. It doesn’t have much effect on the structural integrity of your project, unlike other serious defects like cracks, incomplete penetration, undercut, porosity, etc., which are more unforgiving than spattering.
Is it welding spatter or splatter?
Folks often argue whether to say weld splatter or spatter. But the difference is that splatter means scattering large particles of a substance while spatter means scattering tinier particles of a substance. The American Welding Society (AWS) acknowledges the term spatter and not splatter, so we’ll stick to it in this guide.
Is weld spatter bad?
Tiny balls of hot metal flying around can cause some serious problems that you ought to know before you get into welding.
Listed below are major effects of weld spatter:
Causes of spatter in welding (and how to prevent it)
There are a couple of reasons behind your welding forming spatters. The main factor, however, is the disturbance in molten weld pool when you’re transferring the wire into the weld. This is due to amperage being too low or voltage being too high, resulting in the arch being too cold to keep molten to keep the wire and welding pool molten. The result is a stubbing effect of the wire.
Let’s have a closer look at the MAIN causes of spatter in welding:
Using low-quality welding metal
One of the reasons your welding gets spatter is the material you weld on. Different metals come with varying degrees of weldability. Some metals are non-weldable and you should avoid using them.
Also, you should keep in mind that some metals are marketed as weldable but their alloys are manufactured using cheap non-weldable materials and contaminants which make them low quality and increase their chances of producing spatter.
The solution here is pretty simple: avoid using these low-quality metals. Always make sure you base metal you use for your welding projects is labeled as 100% weldable.
Presence of contaminants on the base metal surface
Another reason why you’re experiencing excessive spattering in your welds could be the surface of the base material you’re welding on being contaminated.
By contamination, we mean the surface harbors undesired elements like dust, dirt, rust. The presence of oil, grease, and marker pen lines will also contribute to spattering.
While not essentially contaminant, the presence of a coating on the metal surface such as galvanized coatings, metal plating, paint, rubber, chrome, etc., can also lead to spatter.
Again, the solution here is straightforward. You just need to ensure you use a clean, shiny base metal surface for spatter-free welding. Anything on the metal surface will definitely lead to spattering, so make a point of completely cleaning the surface to get rid of any dirt and dirt.
For stubborn contaminants like rust, you’ll need to use a grinder and mil scale to clean the rust easily. You can also use the grinder to remove the coating on the area you’ll be welding.
And for grease, oil, and paint, a rag with acetone or paint thinner will help you get rid of them and leave your base metal clean and shiny.
Besides minimizing spattering, using a clean surface will also ensure deeper penetration and clean bead and reduce other welding defects.
Quality of the filler metal
Sometimes you might be surprised to find out that the quality of filler metal you have been using has been the culprit behind too much spatter on your welds.
Even if you use the right welding technique and set your machine correctly, a low-grade filler will still hit your welds with a spatter.
Just as we have seen with the base metal, some companies tend to compromise the filter metal quality by adding non-weldable components which directly result in spatter. Such filers are easy to spot since they fall in the low price range.
You can avoid spatter caused by low-quality filler by researching and investing in quality consumables. While the low-end fillers will help you save a few cents, you’ll realize that the few cents aren’t really worth it when you start dealing with the spatter.
But then again, you don’t have to invest in the most pensive fillers for the best welding results.
Just makes sure you do your research well to find the right type of filler metal to use for your base metal and you’ll end up with the least spatter on your workpiece.
If you don’t sore your consumables correctly, they’ll most likely get contaminated with undesired elements like dirt, dust, and oil. They can also easily catch rust if you store exposed them for a long time.
If the dirt and rust directly enter the weld, it is sure to cause spattering.
The best solution here is to ensure you cover your consumables completely when not in use to ensure they don’t get contaminated by these elements.
In case you use stainless steel rods, they’re easier to handle since they don’t rust easily. But you should never leave them outside. And in case you do, make sure you wipe them before using them on your weld.
Likewise, you should also cover your MIG welding spool when not in use. Always keep the wire in a bag if you don’t intend to use it for some time to keep moisture from building up on the coil and causing rust. If your welding spool cover is sealed, then there’s no need to keep the wire in the bag.
Stick welding rods don’t require much care as the flux on the rods easily removes the air and other impurities from your welds during the welding operation.
However, wet or oily rods for stick welding can produce spatter, so you should also consider keeping them covered in a container or bag.
Wrong welding method
You might have everything set up correctly, and a clean base metal surface. But if you’re not using the correct welding method, you’re sure to get those annoying spatter in your work.
It doesn’t matter whether you’re a MIG or stick welder, employing the wrong welding method will still hit back with a lot of spatter.
The fix here is to always employ the right technique to ensure you get nice, high-quality welds at all times while keeping the spattering minimal.
Proper MIG welding technique:
If you’re a MIG welder, you want to start by ensuring you hold your weld gun at an angle of 15 degrees of vertical—no more, no less—usually known as the flat gun angle.
Though holding the gun at this angle makes it hard for you to see the weld puddle, it’s a crucial skill to learn for spatter-free welding.
To get this angle right, we suggest rehearsing your weld before you can crank the arch. Simply hold the gun and take your hand through the length of the weld and try to keep the gun upright the entire period.
If you find it challenging, try changing your body position or setup so that you can hold the gun at the right angle.
Beginner welders also tend to hold the gun too far from the puddle to enable them to see the puddle better. Unknown to them, however, this leads to a long welding arch.
A long arch makes the filler metal drip and splash instead of coming out in even spray. Try as much as possible to keep the arch length between ½ to ¾ inches.
PRO TIP: When using the proper welding technique, your MIG welding will let you know if you listen to it. It should produce an even and steady sizzling sound. If you hear anything else other than this, say pops and cracks, that means you’re making spatters. Stop immediately and adjust things to prevent excessive spattering.
The direction in which you move when welding can also contribute to spatter in welding. The right direction depends on the material yore welding. If you want high and consistent heat, pull your weld. If you need more heat dispersion, pushing will work better for you.
You should also move at the right speed for MIG welding to ensure clean welds. Moving your gun too fast or too slow impacts not only the bead quality but also causes weld spatter.
Correct SMAW (stick) welding technique:
Stick welding isn’t too demanding for the proper welding technique compared to MIG welding. Here, you just need to concentrate on the direction and speed of your welding.
Pulling tends to create more spatter in SMAW than pushing. But this doesn’t mean you should only use the pulling technique because it doesn’t form a spatter. Where you ought to push, just push.
As for the travel speed, you should move at the right rate for the best consistent results. Keep in mind that if you move too fast, you’ll end up with more spatter!
Welding machine settings
Yes, using your welding machine with the wrong settings will also cause the formation of those spatter that give your welds an unsightly appearance.
These machines present you with a list of settings, all of which you should set correctly to ensure perfect welding results. The settings are easy to adjust as they come clearly labeled on the printer (but you can also reply on your user manual to check the different settings).
The manufacturer recommended settings will give you a good start when setting up your machine correctly. But you should also play with the settings to ensure you deliver spatter-free work.
Focus on these key settings on your welding machine:
The level of amperage you set your machine to will have a direct effect on spatter formation. If you use high amperage, the weld pool will easily splash and spatter.
To avoid this, set your machine to the lowest recommended amperage depending on the gauge of the metal you’re working on. But don’t go below the recommended level, or you’ll end up with a weld failure.
You should note that high amperage delivers deeper penetration. so, if you need deeper penetration in your weld, you might have to go for the high amperage but live with some spatter on your workpiece.
The other important setting is voltage and also revolves around current. Voltage behaves in an opposing manner to amperage in relation to spatter in welding.
When you set your machine to a voltage level that’s too low, the spatter increases. This is simply because low voltage forces the filler wire to drip into the pool in bigger beads. And bigger beads result in splashing, thus spatter.
If you want a bead that penetrates thick material easily, you should consider setting your machine to high voltage and low amperage—this combination results in reduced spatter and clean and smooth weld beads.
However, you should avoid setting the voltage too high as this will make it hard for you to control the arch and limit deep penetration.
If your recommended machine voltage level is producing too much spatter, we advise you to try increasing it in small increments until the bead becomes smooth and spatter-free.
Wire feed rate
As a MIG welder, you should also mind your wire feed speed for a clean weld. MIG welders usually use electrode/filler material combination, a setup that enables you to lay down beads at a pretty high rate.
However, it can also lead to the formation of spatter. Irregular or fast wire feeds will always result in excessive spatter. A wire feed rate that’s too fast for your project will most likely result in spatter as the pieces of wire break and end up splashing in the weld pool and form those round sticky balls.
The wire feed rate is directly related to the current (amperage and voltage) settings. That is, you can easily adjust the heat of your weld by playing with amperage and voltage settings as described in our previous welding machine settings section.
To prevent spatter due to incorrect wire feed rate, you should start using wire feed rate recommended for the amperage you have set your welding machine to. In other words, your welder settings ought to be hot enough for your wire to melt before hitting the puddle at a healthy pace.
If the wire becomes too hot, it melts far away from the pool and causes spatter from the huge space between your weld puddle and liquid metal traveling towards the puddle. And if it melts near the gun nozzle, it makes its tip sticky.
The buildup of this residue, in turn, causes inconsistent feed rate, further facilitating spatter production.
Reduce the feed speed if you’re getting spatter. But don’t be too slow, or you’ll end up with the same thing you’re running from—spatter.
Type of shielding gas used
The type of shielding gas you use is another crucial determinant of how your weld looks and whether the spatter will form or not. Many gasses are available for MIG should but the two most common options include Carbon (ii) oxide (CO2) and Argon.
So, which is the best shielding gas to use for MIG welding?
Use a blend of the two gases above (CO2 and Argon) for minimal spatter at average pricing. When used in the correct ratios, a mixture of these two as your shielding gas will help you significantly reduce spatter.
You can use the gases in ratio 95% Argon to 5% Co2 to 80% Argon to 20% Co2. The thicker the metal you’re welding, the higher amount of Co2 you should use.
Using the right combination of these gases for the right gauge of metal makes it easy for you to achieve clean welds with reduced spatter.
Other methods to reduce spatter in welding:
Cleanup your weld gun nozzle
Your weld gun isn’t spared when in an event of spattering. It can get spattered just as your workpiece and anything else nearby. With time, the gun can become gunked up, disrupting the arch and gas flow and causing more spattering in your welds.
If you have done everything else correctly and the spatter issue doesn’t seem to go away, try scrapping the gun off your gun tip to make it clean. You can use nose pliers to help you easily get this spatter off your gun.
However, you don’t have to wait for the spatter to form to start cleaning your gun. If you can clean it after every heavy use, you’ll be able to keep off spattering from most of your welding projects.
Adjust the working clamp
A loose connection in your working clamp can also cause the welding arch to fluctuate, which ultimately leads to spatter formation. Don't confuse them with table clamps.
You can avoid this by ensuring your clamp tightly bites your working surface before placing the base metal. If possible, put the clamp closer to your welds for reduced spatter.
How to control spatter in welding?
We have already discussed the major causes of spatter in welding and how to prevent them. But there are additional techniques you can use to control spatter formation.
In this section, we have outlined the most effective methods you can employ to stop or control excessive spatter when welding.
If you’ve been wondering how to keep spatter from sticking on your workpiece, then anti-spatter spray is the answer. There are multiple sprays available, all featuring varying sets of ingredients, but they all work well to keep the flying welding droplets from sticking on your workpiece.
You just need to spray the area you want to keep spatter-free. Then, as you get down to welding, the spatter will stick on the coating and not the base metal. When you finish welding, simply use a cloth to wipe off the spatter droplets. No need to use a grinder!
WARNING: Be careful how you apply the spray. If it gets into the place you want to weld, its formulation will work hard to keep the weld filer from sticking to your base metal just as it keeps the spatters from sticking on the same. AVOID spraying along the seams for high-quality, defect-free welds.
Anti-spatter welding tape
A wedding tape also helps you eaisly control spatter by keeping it from forming where you tape. However, it won't be as convenient as the best anti-spatter sprays.
Usually made from aluminum, this tape gives the spatter something else to hold on other than your base metal. Simply place it alongside your seam and when you’re done, simply peel it off to reveal a smooth, spatter-free space.
Unlike the spray method, welding tape won’t affect your welding bead in any way. Aluminum welding tape is also pricey.
You might be tempted to use tapes made from other materials to save money. But remember that these materials can easily melt or burn when spattered. In worst cases, they can cause a fire!
How to clean up weld spatter?
As we said earlier, cleaning up weld spatters isn’t an easy job. You’ll have to spend hours working on these stick beads to remove them from your workpiece. This can affect your productivity.
Luckily, there are a few tools you can use to help you easily get rid of spatter. These tools usually apply blunt force on the spatter to remove it and leave you with a smooth surface. They include a chisel and hammer or a grinder and have been used for years and years to remove spatter and they work just fine.
The cold chisel and hammer method
You can use a cold chisel to clean up the spatter by placing it against the spatter beads and then tap with the hammer. The downside of this method is that it’s time-consuming and leaves small gouges and nicks on your base metal.
Grinder for removing spatter
The angle grinder is another popular method for cleaning welding spatter. It’s the best method for removing medium to large spatter beads. It helps you knock off the spatter without interfering with the base metal like a cold chisel. For the best results, we suggest using a flap wheel type of grinder.
TIP: You can finish up the chiseling or grinding work with a belt sander if you want to achieve a completely smooth and shiny surface. However, sanding is only meant for cosmetic purposes as it doesn’t add to removing spatter. If looks aren’t important for you, you can ignore this part.
Cleaning up spatter on welding table:
As we explained earlier, spatter balls can land on anything, including your workbench, and make it lumpy. Even the best welding table in the market can't resist it on its own. To prevent this, advise you to apply the weld spatter-resistant coating on your welding table to spatter-proof it.
Apply a coat of this spray on your entire welding table before you start welding. When you’re done welding, you’ll just need to use a cloth to wipe the droplets for a clean tabletop to leave it spatter-free.
This is a much safer method to keep your welding spatter-free than grinding which can easily damage your welding table.
Alternatively, you can invest in a spatter-resistant table. A spatter resistant table features a top that’s completely resistant to spatter. This prevents the tiny molten particles of metal from sticking on it and saves you time and money on cleanup.
Most of these tables feature grey cast iron construction whose graphitic microstructure makes them spatter-proof.
As the surface of these tables age, the better they become at stopping spatter from adhering on their surface. As this metal ages, the graphite (carbon) moves to its surface and becomes darker in color.
An added benefit of using this type of material for welding tables is that it doesn’t expand significantly like steel when exposed to heat.
Spatter is a headache that every welder will have to deal with, whether beginner or experienced. The good thing is that this issue can be easily put under control by putting the right measures in place. With all the information you have gained in this guide, we’re confident that you’re well equipped to face and deal with spatter in your welding projects and increase your possibility of creating smooth and clean welds.