Troubleshooting guide › Weld defects › Spatter
Spatter is the small balls of metal thrown out of the arc that stick to the plate and the nozzle. A little is normal with CO2 MIG and with ARC welding. A lot means wasted wire, blocked nozzles, burnt-out contact tips and an hour of grinding per shift. Most spatter comes from the voltage-to-wire-speed balance being wrong.
Reviewed by the Cruxweld technical team, October 2026. Settings are starting points to confirm on a test piece; acceptance is decided by the code or drawing the job is built to. Checks marked “call” are for our technical team.
Fine metal beads stuck around the weld, on the plate and inside the nozzle. Heavy, large spatter balls mean the arc is unstable; fine mist-like spatter is more typical of CO2 and is harder to remove.
Illustration, not a photo. Orange marks the defect.
The wire stubs into the pool and explodes, throwing metal out.
Large droplets form and fall off unevenly (globular transfer), each one spraying.
CO2 gives a rougher arc than argon mixes.
Poor current pick-up makes the arc flicker.
Rust and oil cause mini-explosions in the pool.
Current drops and the arc becomes unstable.
Self-shielded flux-cored and some electrodes need electrode negative; most solid wire needs electrode positive.
A loose or rusty earth clamp makes the arc unstable.
| Process | Typical reason on this process | What to do |
|---|---|---|
| MIG / MAG on CO2 | Globular transfer: voltage too high or too low for the wire speed, long stick-out, dirty plate. | Tune voltage until the arc crackle is steady, stick-out 10-15 mm. Ar-CO2 mixed gas cuts spatter sharply if the job allows it. |
| Flux-cored | Voltage too low, wrong polarity for the wire (most gas-shielded FCAW runs DC+, some self-shielded wires DC-), damp wire. | Check the polarity the wire calls for, raise voltage one step, keep wire dry. |
| ARC / MMA | Arc too long, current too high, damp or wrong-polarity electrodes, arc blow near the end of a plate. | Short arc, current in the electrode range, bake electrodes, move the earth clamp. |
| TIG | Almost none. Spatter on TIG means the filler is being melted in the arc instead of in the pool, or the tungsten is contaminated. | Feed the filler into the front edge of the pool, regrind the tungsten. |
| Spot welding | Called expulsion: current too high, force too low, dirty or poorly fitted sheets. | Drop one tap step, tighten the spring, clean the sheets. |
MIG / MAG, 1.2 mm ER70S-6 on 6 mm mild steel, low spatter. A starting point only; confirm on a test piece of the same plate.
| Gas | 80/20 Ar/CO2 |
| Current / voltage | about 200-240 A / 24-27 V (spray) |
| Wire speed | about 7-9 m/min |
| Stick-out | 12-15 mm |
| Anti-spatter | spray on the nozzle, not on the joint |
Typical values for mild steel. Your wire, plate condition and machine will move them. Our technical team can set them with your operator on a video call.
Spatter is cosmetic unless it has fused to the plate in a way that leaves a stress raiser, or has blocked the nozzle so badly that porosity follows. Count the time spent chipping and grinding per metre of weld: that is the real cost, and the cost calculator can show it.
It makes spatter easy to remove; it does not stop it. Fix the settings first, then use spray or a nozzle dip on parts that must look clean.
Usually yes. An inverter holds the arc voltage steadier through mains fluctuation and lets the arc be tuned finer, which reduces short-circuit spatter. Dirty plate and wrong settings give spatter on any machine.
Sometimes. Pure CO2 always gives more spatter than Ar-CO2 at the same settings. If the spatter rises suddenly with no change of settings, check the gas flow and the cylinder.
Inverter MIG machines with electronic arc control reduce spatter at the short-circuit to spray transition because they react to each droplet in microseconds; a tapped transformer set cannot do this.
Send a photo of the weld or cut, your machine model, consumable and plate thickness. Our technical team replies on WhatsApp with the likely causes and the next checks to make.
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