MIG vs STICK

Technical Series · Part 4

Two processes, one arc. Two very different approaches. 

DJR Welding LLC · May 2026 · 5 min read

A MIG weld can look perfect and have zero fusion to the parent metal. That’s a scenario we see regularly — and more often than not, people blame the process when the real problem is improper setup and technique.

Stick is far less forgiving of insufficient amperage — the arc instability usually makes the problem obvious before a visually acceptable weld is completed.

MIG doesn’t behave that way. Set it cold and it keeps running. The bead looks fine. The machine gives no warning. The fusion isn’t there.

1. Two processes, one arc

Stick welding — formally SMAW, Shielded Metal Arc Welding — is one of the oldest electric arc processes still in regular use. The flux-coated electrode does two jobs at once: it carries the current and provides its own shielding as it burns. No gas cylinder. No wire feeder. No regulator. Simple equipment, forgiving process, and a long track record in structural and field work.

MIG welding — formally GMAW, Gas Metal Arc Welding — feeds a continuous wire electrode through a gun while an external shielding gas protects the puddle from atmospheric contamination. It’s fast. It deposits more metal in less time. And in a controlled shop environment on clean prepared material, it earns that reputation.

Both processes use an electric arc to melt and fuse metal. That’s where most of the similarity ends.

2. Where stick has the advantage

Wind can quickly ruin MIG shielding gas coverage. The puddle loses protection. The result is porosity, contamination, and poor fusion. Outdoor and field work in anything but calm conditions is a real problem for GMAW.

Stick doesn’t have that problem. The shielding is built into the electrode. You can weld in wind, on dirty metal, on rusty metal, in positions that would challenge a MIG setup. Pipelines, bridges, heavy structural fabrication — stick is still doing that work for exactly these reasons.

Stick also handles a wider range of base metals and material conditions without the prep requirements MIG demands. Less equipment. Less setup. More tolerance for the conditions you actually find in the field.

Stick also wins on setup time. In the field, dragging out a suitcase welder, hooking up gas, checking the wire, hoping the metal is clean enough — that’s time and variables before the arc even starts. Wire can bird nest. Gas can run low or get knocked off. Sometimes it’s faster and simpler to just grab the stinger and go, even if the process takes a little longer on the weld itself.

3. Where MIG has the advantage

Deposition rate. MIG lays down more metal faster than stick. On clean, prepared material in a shop environment — sheet metal, automotive work, light gauge steel, moderate thickness structural fabrication — that speed advantage is real and it matters in production.

The tradeoff is equipment and setup. Gas cylinders, regulators, wire feeders, liner maintenance, drive rolls. More to configure, more to maintain, and more variables that have to be right before welding begins.

The common misconception is that MIG can’t weld thicker material. That’s not accurate. With proper joint preparation — beveling, fit-up — and the right shielding gas selection, MIG is capable of producing sound, code-compliant welds on thicker sections. Transfer methods and how they affect thicker section welding are coming in a future post.

The limitation isn’t the process. It’s the settings and the prep.

4. Cold lap — the real problem with MIG

That last row is the one that matters most.

MIG doesn’t tell you when it’s failing. Set the machine cold, weld over mill scale, and you can lay down a bead that looks completely acceptable — smooth, consistent, no visible defects — with little to no fusion to the base metal. Cold lap — overlap without fusion, typically caused by low heat input and poor wetting — is one manifestation of lack of fusion and one of the major risks in improperly set MIG welding. It will look like a weld. It is not a weld.

Tacks made with a MIG machine set too cold over mill scale will look fine and come off clean by hand. The welder has to know.

A common example: running 0.035 wire on 1/4” plate at settings better suited for 1/8” material. The bead goes down. It looks fine. The fusion isn’t there.

5. In the field

The scenario plays out in shops constantly. A fabricator is tacking together a mild steel assembly. The MIG machine is set a little cold — maybe it wasn’t adjusted from the last job, maybe someone dialed it back and forgot. The material has mill scale on it. The tacks go down fast, they look clean, nobody questions them.

Then the assembly goes into service or gets moved and a tack lets go. Or worse — it holds through handling, gets fully welded over, and the lack of fusion is now buried inside a finished weld.

With stick, that scenario is much less likely. The process resists it naturally. With MIG, it requires the welder to understand what’s happening at the arc — settings, material condition, and shielding gas — well enough to know when the weld isn’t actually fusing.

This is why MIG rewards knowledge. It punishes assumption.

6. How to avoid it

Cold lap and lack of fusion are preventable. These are the basics:

• Clean to bright metal on critical joints — mill scale is not a suitable welding surface for MIG.
• Set voltage and wire speed for the material thickness you are welding. Don’t reuse settings from the last job blindly.
• Watch puddle wet-in at the toes, not just bead appearance. A smooth bead surface does not confirm fusion.

7. Questions we hear on this

Is MIG weaker than stick?

Not inherently. A properly executed MIG weld on prepared material with correct settings and shielding gas can match stick weld mechanical properties. The process isn’t the weakness — improper settings and poor prep are.

Why do so many structural applications still use stick?

Versatility, field conditions, and code acceptance. Stick performs well on dirty and rusty material, handles wind, requires minimal equipment, and has a long track record in structural and pipeline work.

What causes cold lap in MIG welding?

Insufficient heat input — typically from machine settings being too low — combined with surface contamination like mill scale or rust. The arc deposits metal on top of the base metal without achieving proper fusion. It can look like a good weld.

Can you tell a cold lap weld by looking at it?

Often not. That’s the problem. Cold lap and lack of fusion are subsurface defects. Visual inspection often won’t reliably detect them. Proper settings and prep are the prevention. Destructive testing or NDT methods are the detection.

Which process should a beginner learn first?

Stick first. It teaches arc control, heat management, and gives you immediate feedback when something is wrong. That foundation makes you a better MIG welder.

8. TLDR — Key Facts

Questions on this or topics you want covered next — drop them in the comments or reach out directly. More coming.