Is Arc Welding Stronger Than MIG?: Unveiling the Truth

The morning my client questioned my weld

Tyler Marsh had been welding for six years when a farm customer walked into his shop, pointed at a repaired loader bucket, and asked the question that every welder eventually hears: “But is this as strong as the other kind?” The customer had read an online forum where someone claimed that stick welding — what most people still call arc welding — always produces a stronger joint than MIG. Tyler had just finished the job with a stick welder because the bucket was caked in rust and mud, and he had no way to clean it properly. He knew the joint was sound. He also knew that “trust me” is not an answer a paying customer wants to hear.

So he did what any curious tradesperson does. He dug into the metallurgy, the codes, the tensile numbers, and the real-world trade-offs. What he found surprised him: the honest answer is not a simple winner. It is a story about penetration, shielding, contamination, geometry, and the skill of the person holding the stinger.

If you have ever stood in front of two welding machines wondering which one will give you a joint that will not crack under load, this guide is for you. We are going to settle the arc-versus-MIG strength debate with real numbers, real codes, and real job-site scenarios — and we will tell you exactly when each process wins.

Key Takeaways

• Neither process is universally stronger. Both Shielded Metal Arc Welding (SMAW, commonly called stick or arc welding) and Gas Metal Arc Welding (GMAW, known as MIG) can produce full-penetration welds that are stronger than the base metal they join.
• Arc welding usually wins on dirty, thick, and outdoor work because the flux coating cleans the metal as it burns and no external shielding gas can be blown away by wind.
• MIG welding usually wins on thin material, clean metal, and production speed, producing consistent, low-contamination welds with less spatter and less distortion.
• Joint design, preparation, heat input, and operator skill matter more than the process name — a careful MIG weld on clean steel will outperform a rushed, undercut stick weld every time.
• Published tensile strengths overlap almost completely. Common stick electrodes (E6010, E6011, E7018) and common MIG wires (ER70S-3, ER70S-6) all yield joints in the 60,000–70,000 psi range on mild steel.

What Does “Stronger” Actually Mean in Welding?

Before we can crown a winner, we have to agree on what we are measuring. On the shop floor, the word “strong” gets used to describe at least five different things, and they do not always point to the same process.

Tensile Strength

This is the amount of force, measured in pounds per square inch (psi) or megapascals (MPa), required to pull a test bar apart. It is the number printed on the AWS classification of a consumable. An E7018 stick electrode and an ER70S-6 MIG wire are both “70” consumables, meaning both are rated for a minimum tensile strength of 70,000 psi (482 MPa) in the deposited weld metal. On paper, they are identical.

Penetration

Penetration is how deep the weld fuses into the base metal. A weld sitting on top of the plate like a bead of glue is weak no matter how pretty it is. Deep, complete fusion — where the weld root melts into both pieces — is what carries structural load. Penetration depends heavily on amperage, arc voltage, travel speed, arc length, joint geometry, and polarity.

Ductility and Toughness

A joint that is extremely hard can also be brittle. Toughness is the ability to absorb energy and deform without fracturing — critical for structures that see shock, vibration, or cold temperatures. The shielding system and the chemistry of the flux or gas directly influence hydrogen content and notch toughness.

Freedom from Defects

Porosity, slag inclusions, lack of fusion, and cracks reduce the load-bearing cross-section of a weld. A nominally “stronger” process that consistently traps slag is not stronger in practice. This is where process choice and operator technique intersect.

Heat-Affected Zone (HAZ) Integrity

Every weld creates a zone beside the joint where the base metal’s microstructure has been changed by heat. Excessive heat input can soften aluminum and certain steels; too little can cause cold lap. The process that gives you the cleanest control over heat input usually gives you the healthiest HAZ.

Keep these five definitions in mind. Most of the confusion in the arc-versus-MIG debate comes from people comparing different categories — one person means penetration, another means tensile rating, and a third means “it looks solid to me.”

Understanding Arc (Stick) Welding

How the Process Works

In Shielded Metal Arc Welding, an electric arc is struck between a consumable flux-coated electrode and the workpiece. The arc melts both the electrode tip and the base metal, forming a pool of molten metal that solidifies into the joint. The flux coating does three jobs at once: it ionizes the arc path for stable striking, it releases shielding gases that blanket the molten pool, and it forms a layer of slag that floats impurities to the surface and slows the cooling rate.

Because the electrode is short and hand-held, the welder can reach into corners, overhead positions, and open-root joints that a bulky MIG gun cannot reach. That versatility is why arc welding remains the default process for field repair, pipe root passes, and heavy structural work.

Where Arc Welding Gets Its Strength

The flux coating performs a metallurgical cleaning action as it burns. Iron powder and alloying elements in the coating help transfer more heat and metal into the joint, while the gas shield protects the puddle from oxygen and nitrogen. High-quality electrodes such as E7018 are low-hydrogen by design — they are baked to remove moisture and must be stored in a rod oven, because hydrogen absorbed into a weld is a leading cause of cracking.

Stick welding also handles contaminated base metal better than almost any other process. Rust, mill scale, paint overspray, and light oils are broken down by the flux action rather than being trapped in the weld. That is a genuine strength advantage on real-world repair work where grinding the piece to bare, shiny metal is impractical.

For deeper technical background on consumable classifications, the American Welding Society (AWS) publishes the specification documents that define every electrode and wire classification used in North America.

Typical Strength Numbers

Those numbers are minimums for the deposited weld metal, not the joint. The as-welded joint strength also depends on the base metal, the joint geometry, and whether the weld achieved complete fusion.

Understanding MIG Welding

How the Process Works

Gas Metal Arc Welding feeds a continuous solid wire electrode through a welding gun at a metered rate. An inert or active shielding gas — commonly 75% argon / 25% CO₂ for steel — flows out of the nozzle around the arc. The wire melts into the puddle, the gas keeps oxygen away, and the weld solidifies without a slag layer to chip out later.

The wire feed means the welder keeps pulling the trigger and the machine keeps supplying both filler and current. That continuity is the source of MIG’s famous speed advantage: no stopping to change rods, no slag to remove between passes, and a very high deposition rate relative to the amount of spatter produced.

Where MIG Welding Gets Its Strength

MIG’s biggest strength is consistency. The wire feed speed and voltage are dialed in on a chart, and once set, the machine delivers the same heat and same filler metal every inch of the weld. That repeatability reduces the human-variable defect rate on production lines and makes it easier for newer welders to reach acceptable quality quickly.

Because there is no flux coating, the weld pool stays visible. The welder can watch penetration happen in real time, adjust travel speed immediately, and produce very clean, low-spatter beads with excellent tie-in at the toes of the weld. On thin sheet metal, MIG’s ability to run at lower amperage with short-circuit transfer reduces burn-through dramatically.

Shielding gas selection has a direct effect on weld quality and is one of the most under-appreciated variables in the process. Getting the pressure and flow right matters as much as the wire — we covered this in detail in our guide to MIG welding gas settings.

Typical Strength Numbers

Notice the overlap: a standard ER70S-6 MIG wire and a standard E7018 stick electrode are rated identically at 70,000 psi. The consumable itself is not where the processes separate.

Arc vs. MIG: Head-to-Head Strength Comparison

Here is the direct comparison most people are looking for, laid out across the variables that actually decide which joint survives in service.

The pattern is clear: the two processes win in different environments rather than one dominating the other. Understanding why requires looking at the physics of how each arc delivers heat.

Factors That Determine Which Weld Is Actually Stronger

1. Base Metal Thickness

On plate thicker than 1/4 inch, stick welding’s concentrated arc and deep-penetrating electrodes make it a natural choice. A 1/8-inch E6010 running 90–125 amps on 3/8-inch plate can cut a root gap open and fuse the joint root in a single pass. MIG can certainly weld the same thickness, but it typically requires multiple passes and careful interpass temperature control.

On sheet metal below 1/8 inch, the advantage flips. Stick welding puts a large amount of heat into a small piece of metal because the electrode diameter and amperage floor are higher than the sheet can tolerate. MIG’s short-circuit transfer mode can be dialed down to 130–150 amps with 0.023-inch wire and weld 20-gauge steel without blowing holes through. For anyone working on automotive panels or thin ductwork, this is decisive — and we covered similar thin-metal strategies in our thin metal arc welding tips.

2. Surface Condition

This is the single biggest real-world differentiator. Welding over rust, mill scale, paint, or oil introduces oxygen and contaminants into the weld pool. MIG is extremely sensitive to this: trapped gas and oxide inclusions show up as porosity, which directly reduces the effective cross-section carrying load.

Stick electrodes — particularly cellulose-coated types like E6010 — actively burn through and blow contaminants out of the arc zone. On a rusty piece of farm equipment, structural repair with a stick welder is not laziness; it is sound engineering practice, provided you still gouge out and replace any crack that has propagated into the plate.

3. Joint Design and Position

A V-groove butt joint on 1/2-inch plate with a 60-degree included angle and a 1/4-inch root face is a classic stick application: E6010 hot pass followed by E7018 fill and cap. In the same joint, MIG would require a larger groove or a backing strip to ensure root fusion unless pulsed-MIG or spray transfer with high heat input is used.

Overhead and vertical-up work changes the calculus. A skilled welder can run E7018 vertical-up with excellent control because the flux supports the puddle. MIG in the vertical-up position requires carefully tuned voltage and wire speed to keep the weld from sagging, but many fabricators find it easier to keep a consistent stack-of-dimes appearance once the machine is set.

4. Heat Input and Distortion

Heat input is calculated as (volts × amps × 60) ÷ (travel speed × 1000), expressed as kJ/mm or kJ/in. Higher heat input means a wider heat-affected zone, more distortion, and — in some steels — a softer HAZ.

Stick welding generally runs at higher heat input for a given joint because of the sustained high amperage needed to maintain the arc through the flux. MIG, especially with a well-tuned short-circuit setting, can put less total energy into the plate for a comparable fillet on thin material. If distortion control on sheet assemblies is your priority, MIG wins. If you need to burn through a mill-scale-covered structural member and get deep fusion in one pass, stick wins.

5. Operator Skill and Consistency

This factor is impossible to ignore. Strength is a property of the finished joint, not of the process brochure. A welder who has run ten thousand miles of 7018 will consistently out-produce a beginner on a MIG machine, and a MIG operator who has learned to read the puddle will out-perform a stick welder who drags too fast and leaves lack of fusion.

Research in weld quality consistently finds that human technique accounts for a large share of defect rates. The American Welding Society’s certification programs exist precisely because the process name alone does not guarantee a qualified weld — see the AWS standards page for the qualifications that structure the industry.

6. Hydrogen and Cracking Risk

Hydrogen-induced cracking is a serious structural failure mode. Stick electrodes like E7018 are formulated as low-hydrogen, and they absorb moisture from the air if left out — which is why welders keep them in heated rod ovens at 250–300°F. Solid MIG wire does not carry a flux coating, so it introduces essentially no hydrogen from the consumable itself, giving MIG a quiet advantage on crack-sensitive steels as long as the base metal and gas are clean and dry.

The U.S. Occupational Safety and Health Administration regulates ventilation around welding fumes precisely because flux-burning processes release more particulate — you can review the requirements in OSHA standard 1926.353 on ventilation and protection in welding, cutting, and heating.

Real Job-Site Scenarios: Which Process Wins?

Scenario 1: Repairing a Rusted Loader Bucket

Winner: Arc welding. The steel is coated in rust and hardened soil, access is awkward, and the machine may be sitting outdoors in a breezy yard. An E6011 or E7018 rod will burn through the contamination and produce a structural fillet without worrying about shielding gas being blown away. MIG would require extensive grinding, and any gas shielding would be unreliable in open air.

Scenario 2: Fabricating a Thin-Wall Steel Frame

Winner: MIG. With 0.030-inch wire and a 75/25 gas mix, you can weld 16-gauge tube with minimal distortion, clean beads, and no slag to disturb between passes. Trying to stick-weld 16-gauge tube invites burn-through and excessive warping.

Scenario 3: Structural Steel in a Shop Environment

Depends on the shop. Structural fabricators frequently use both: MIG (or flux-core) for out-of-position fillets and production welds, stick for field erection and root passes where the parts cannot be fit up perfectly. AWS D1.1 Structural Welding Code — Steel permits all of these processes when qualified procedures are followed.

Scenario 4: Pipeline Root Pass in the Field

Winner: Arc welding. The open root on pipe, positional requirements, wind, and the need for a clean, deep-penetrating root make E6010 the industry standard for the root, with E7018 or fill wires completing the joint. MIG is used more often in shop-based pipe fabrication where fixtures and shielding can be controlled.

Scenario 5: Aluminum Repair

Neither is the first choice. Aluminum welding is dominated by TIG (GTAW) for control and MIG for speed on thicker sections. Stick welding aluminum is possible with specialized electrodes but produces porous, difficult-to-control results. If aluminum is your primary material, the better question is MIG versus TIG — and we have broken that down in our MIG versus TIG comparison.

Common Myths About Arc and MIG Strength

Myth 1: “Stick welds are always stronger than MIG welds.”

False. When both welds are made to the same specification, on the same material, with a qualified procedure, their tensile strengths are equal or near-equal. The strength lives in the joint design, the fusion, and the technique — not in the label on the machine.

Myth 2: “MIG is only for hobbyists.”

False. MIG is the dominant production process in automotive manufacturing, shipbuilding, pressure vessel fabrication, and heavy equipment assembly. Modern pulsed-MIG and synergic machines reach quality levels that meet the same structural codes as stick welding.

Myth 3: “More amps always means a stronger weld.”

False. Excessive amperage causes undercut, burn-through, excessive dilution, and a coarse HAZ. Proper amperage is a range matched to material thickness and electrode or wire diameter — overshooting it makes the joint worse, not better.

Myth 4: “If it looks good, it is strong.”

Only partly true. A uniform bead usually indicates consistent travel speed and correct settings, but lack of fusion can hide beneath a perfect-looking surface. That is why critical joints are validated with destructive bend tests and non-destructive radiographic or ultrasonic inspection rather than by eye alone.

Cost, Speed, and the Economics of Strength

Strength per dollar matters when you are running a business. Stick welding equipment is inexpensive — a basic buzz-box arc welder can be had for a fraction of a quality MIG machine, and the consumables are cheap per pound. There is no gas cylinder to rent, no liner to replace, and no drive roll wear.

MIG wins on total production cost for repetitive work. The deposition rate is higher, the cleanup time is near zero, and the learning curve means less scrap. In a shop welding fifty identical brackets a day, MIG’s speed advantage typically offsets the higher consumable and gas costs many times over.

For a full breakdown of how equipment choice affects day-to-day operating cost, our guides to flux-core welding and flux-core versus MIG go deeper into the gasless alternatives.

What About Flux-Core Arc Welding?

Flux-core welding (FCAW) deserves a mention because it blurs the line between the two processes. It uses a MIG-style wire feed machine, but the wire is hollow and packed with flux — which means it self-shields like a stick electrode. Dual-shield flux-core adds an external gas on top of the internal flux for maximum deposition and penetration.

In terms of raw deposition rate and penetration, flux-core often beats both processes on heavy plate. It is widely used in structural steel erection for exactly that reason. The trade-off is more smoke, more slag, and more spatter than solid-wire MIG. Our complete guide to flux-core welding strength covers the specifics.

How Weld Strength Is Tested and Certified

Professional shops do not argue about strength — they test it. The common methods are:

• Tensile test: A machined bar is pulled until it breaks; the peak force is recorded.
• Bend test: A specimen is bent to a specified radius; cracking indicates lack of fusion or brittle weld metal.
• Charpy V-notch impact test: Measures toughness at temperature — essential for cold-weather and pressure applications.
• Visual and dimensional inspection: Checks for undercut, overlap, porosity, and profile per the applicable code.
• Non-destructive testing (NDT): Radiography, ultrasonic, magnetic particle, and dye penetrant testing locate internal and surface-breaking defects without destroying the part.

Both SMAW and GMAW are qualified under AWS D1.1 and D1.8 for structural work, and under ASME Boiler and Pressure Vessel Code Section IX for pressure-retaining welds. A qualified WPS (Welding Procedure Specification) documents the exact parameters — and when the procedure is followed, the code does not care which process produced the bead.

The broader safety framework around these tests and around shop ventilation is maintained by OSHA’s welding, cutting, and brazing program, which also links to the respiratory protection standards that apply when fume exposure cannot be controlled by engineering controls alone.

Choosing the Right Process: A Practical Decision Framework

If you are standing in front of your welder trying to decide which process to use for today’s job, run through this sequence. It takes about thirty seconds and it mirrors how experienced welders actually make the call.

Step 1: Look at the Metal Surface

Is it clean, shiny, and dry? If yes, both processes are on the table. Is it rusty, painted, oily, or galvanized? If yes, lean toward stick welding — or plan on significant grinding and prep before MIG will give you a sound weld. Galvanized steel in particular releases zinc oxide fume that requires ventilation regardless of process, and the coating must be removed at the joint for either method to fuse properly.

Step 2: Measure the Thickness

Below 1/8 inch, MIG with a small-diameter wire and short-circuit transfer is usually the safer choice because of heat control. From 1/8 inch to 1/2 inch, both processes work well. Above 1/2 inch, stick welding or flux-core becomes more efficient because of penetration depth and deposition rate per pass.

Step 3: Check the Environment

Are you indoors in a controlled shop? Gas-shielded MIG is fine. Are you outside on a windy day, on a job site, or in a drafty barn? Shielding gas will be blown away and your MIG welds will come out porous. In that case, use stick welding or gasless flux-core wire — both are self-shielding and immune to wind.

Step 4: Consider Position

Flat and horizontal welds are easy in either process. Overhead, vertical-up, and out-of-position work reward the right consumable: E7018 vertical-up for stick, or properly tuned spray and short-circuit settings for MIG. If you are welding in a position you cannot reposition the workpiece for, choose the process you have the most practice in — muscle memory beats theory.

Step 5: Ask What Happens If This Weld Fails

A decorative gate that falls over is annoying. A trailer hitch, a load-bearing bracket, or anything holding a person off the ground is a different category entirely. For critical structural joints, choose the process and consumable that the applicable code specifies, follow a written WPS, and get the weld inspected. The strength of a life-safety weld is not a matter of preference.

Mistakes That Make Either Process Fail

Both arc and MIG welds fail for the same handful of reasons. Avoiding these is worth more than any argument about which machine is better.

Poor Joint Preparation

Skipping the grind, leaving a heavy root opening, or fitting up with a large gap forces the welder to fill volume instead of fusing both pieces. A gap that is too wide causes excessive heat input, sagging, and incomplete fusion at the root. Take the time to bevel the edges, set the correct root face, and clamp the parts so they do not pull out of alignment as they cool.

Wrong Settings for the Thickness

Too much heat on thin metal burns through; too little heat on thick metal sits on the surface without fusing — the classic “cold lap” or “lack of fusion” defect. Both failures look similar from outside: a bead that is lying on top of the metal rather than having sunk into it. In MIG, this often means voltage is too low for the wire speed. In stick, it means amperage is too low or the arc is being held too long.

Contaminated Consumables

Damp E7018 electrodes are the number one cause of hydrogen cracking in structural work. Rods left out overnight in humid conditions pick up moisture from the air; when the flux burns, that moisture becomes hydrogen, which diffuses into the cooling weld and can open a crack hours later — sometimes after the job has left the shop. Keep low-hydrogen rods in a heated oven and only take out what you will use in one shift.

MIG wire has its own contamination problem: a rusty or oil-coated wire feed path. Wire that has been exposed to shop humidity will carry surface oxides straight into the puddle, producing porosity that looks like Swiss cheese when you chip the slag off a flux-core bead or etch a MIG weld. Store wire on a dry rack, wipe the liner, and replace drive rolls when they wear flat.

Travel Speed That Is Too Fast

Rushing is the most common beginner mistake in both processes. When travel speed outruns the heat, the weld bead lays proud and narrow, penetration drops, and the toes of the weld do not wet into the base metal. The bead may look tidy — a tight, narrow stack of dimes — but the fusion underneath is incomplete. Slow down until the puddle has time to wash into both sides of the joint.

Ignoring Interpass Temperature

On thick multi-pass welds, each pass re-heats the previous one. If you stack passes too quickly, the heat-affected zone grows and the microstructure of the earlier passes is degraded. Let the weld cool to the interpass temperature specified in the procedure — usually around 400–600°F for carbon steel — before laying the next bead.

Comparison With Related Welding Processes

The arc-versus-MIG question rarely exists in isolation. Most welders eventually need to compare a wider set of options, so here is how the two main processes stack up against their neighbors.

Arc (SMAW) vs. TIG (GTAW)

TIG produces the highest-quality, most precise welds available — it is the standard for aerospace, food-grade stainless, and thin-wall tube. But TIG is slow, expensive, and highly technique-dependent. For raw deposition on thick steel, arc welding beats it comfortably. The trade-off is precision versus speed. If your priority is a beautiful, controlled, X-ray-clean weld on thin material, TIG wins; if your priority is getting structural steel joined quickly in the field, stick wins. Our full TIG versus MIG strength guide covers that comparison in depth.

MIG vs. Flux-Core (FCAW)

Flux-core uses the same wire-feed machine but a hollow, flux-filled wire that self-shields. It deposits metal faster and penetrates deeper than solid-wire MIG, making it the process of choice for heavy structural fabrication. The trade-off is more smoke, more slag, and a messier bead. For a full breakdown, see our comparison of flux-core versus MIG.

Arc vs. Flux-Core

Both handle dirty metal and outdoor conditions. Stick is more portable and needs no gun, liner, or gas. Flux-core is faster and easier to run continuously because you never stop to change rods. On heavy plate in a shop, flux-core usually wins on productivity; on a remote repair with minimal gear, stick usually wins on practicality. We have a detailed look at that matchup in our stick versus flux-core guide.

Stick vs. MIG vs. TIG: The Three-Way View

For a complete side-by-side of all three, our MIG vs TIG vs Stick article covers the full spectrum. The short version: MIG for speed and ease, TIG for precision and beauty, stick for versatility and field durability.

Practical Tips to Maximize Strength in Either Process

For Arc (Stick) Welders

• Store low-hydrogen rods properly. E7018 and similar electrodes belong in a rod oven held at 250–300°F. Rods that have been out for more than a few hours in humid air should be re-baked per the manufacturer’s instructions before use on critical work.
• Strike the arc on a start tab, not on the base metal. Striking directly on the workpiece can leave a hard spot that becomes a crack initiation site if it ends up inside the weld.
• Keep arc length short. Arc length should be roughly the diameter of the electrode core. A long arc introduces atmosphere into the puddle, reduces penetration, and increases spatter.
• Clean between passes. Chip the slag completely and wire-brush before laying the next bead. Trapped slag is one of the most common causes of rejection in radiographic testing.
• Match amperage to electrode diameter and position. A general rule for E7018 on mild steel: about 1 amp per 0.01 inch of electrode diameter for flat work, reduced by 10–15% for vertical and overhead.

For MIG Welders

• Match wire diameter to material thickness. 0.023-inch wire for sheet metal up to 16 gauge, 0.030-inch for general fabrication up to 1/4 inch, 0.035-inch for heavier plate. Using wire that is too thick for the job forces you to run more heat than the material can take.
• Check your contact tip recess. A tip that is too far back or too far forward changes the stick-out length, which changes amperage and penetration. Stick-out of 1/2 inch to 3/4 inch is a common sweet spot for short-circuit MIG.
• Watch the voltage-to-wire-speed balance. Voltage controls the arc length and bead width; wire speed controls the amperage. If the wire is stubbing into the puddle, increase voltage. If the wire is melting back into a ball at the tip, decrease wire speed or increase voltage.
• Keep the liner and drive rolls clean. A kinked or contaminated liner causes erratic feed, which shows up as inconsistent penetration along the length of the weld.
• Use the right gas and flow rate. For steel, 20–25 CFH of 75/25 argon-COâ‚‚ is standard. Too little flow admits air; too much flow creates turbulence that actually draws atmosphere into the shield. Our gas setting guide covers dialing this in.

Universal Rules for Both Processes

• Clean the metal first. Remove rust, paint, oil, and mill scale within at least 1 inch of the joint on both sides. This one step prevents more weld defects than any machine setting.
• Fit up tight. Gaps and misalignment force the welder to compensate with extra heat and filler, which distorts the part and weakens the joint.
• Control heat input. Use the lowest effective amperage and the fastest travel speed that still produces full fusion. This minimizes distortion and keeps the heat-affected zone narrow.
• Preheat when the code says to. On thick plate, cold steel, or high-carbon and alloy steels, preheating slows the cooling rate and prevents hydrogen cracking. Follow the preheat table in the applicable code — not a guess.
• Inspect your work. Look at the toes of the weld, check for undercut, and verify fusion. If the joint is critical, get it tested rather than assuming.

The Role of Codes and Standards

The strongest argument against “which process is stronger” as a question is that codes do not rank processes. They qualify procedures. Under the AWS standards catalog, structural welds made by SMAW, GMAW, FCAW, and GTAW are all accepted when performed under an approved WPS by a qualified welder, with the required inspection completed.

The main codes you will encounter in North American practice are:

• AWS D1.1 — Structural Welding Code, Steel. The primary code for welded steel structures. Covers all commonly used processes with prequalification tables that define acceptable positions, electrode/wire classifications, and joint details.
• AWS D1.2 — Structural Welding Code, Aluminum. Governs aluminum structural welding, where MIG and TIG dominate.
• AWS D1.6 — Structural Welding Code, Stainless Steel. Applies to austenitic and duplex stainless fabrications.
• ASME Boiler and Pressure Vessel Code, Section IX. Governs welding qualifications for pressure vessels, piping, and boilers, where procedure qualification records (PQRs) prove that a given process and parameter set produces acceptable mechanical properties.
• API 1104 — Welding of Pipelines and Related Facilities. The pipeline standard where stick and automated GMAW processes both appear, each with defined acceptance criteria for radiography and bend tests.

Notice what is missing: any statement that one process produces a stronger weld than another. The codes care about the finished joint’s properties, not the method used to achieve them.

Safety Considerations for Both Processes

Strength is not the only thing that matters on a welding job. Both processes carry hazards, and the hazard profiles differ in ways that are worth understanding.

Ultraviolet and Infrared Radiation

Both arcs produce intense UV radiation. According to OSHA, inert-gas welding processes like MIG generate UV at intensities 5 to 30 times that produced during shielded metal arc welding, which means bystanders need protection even when they are not looking directly at the arc. Screens, proper filter lenses, and full skin coverage are required. The details are spelled out in 29 CFR 1926.353.

Fume Exposure

Stick welding generally produces more fume than gas-shielded MIG, because the flux coating decomposes and releases particulate. MIG on coated, galvanized, or stainless steel produces its own fume hazards — including manganese, hexavalent chromium (from stainless), and zinc oxide. OSHA 1910.252 requires ventilation adequate to keep contaminants below permissible exposure limits, and 1910.253 adds process-specific requirements for electric and gas welding.

Electrical Safety

Both processes use open-circuit voltages high enough to shock, and both become more dangerous in wet or confined spaces. Insulate the workpiece, keep electrodes and torch holders dry, and use GFCI protection on portable equipment. In confined spaces, OSHA requires either mechanical ventilation or air-line respirators plus an attendant outside — a rule that applies regardless of which welding process you choose.

Fire and Explosion

Spatter from both processes can travel 30 feet or more. Remove combustibles within a 35-foot radius or cover them with fire-resistant blankets, and keep a charged extinguisher within reach. Flux-core and stick both throw hotter, heavier spatter particles than short-circuit MIG, so the fire risk is slightly higher with those processes in cluttered shops.

Eyes and Skin

Never look at the arc without a proper filter lens, and never leave the helmet up while striking the arc. Arc flash (photokeratitis) is effectively a sunburn of the cornea and it hurts for days. For more on choosing and maintaining protective gear, see our welding safety tips.

Which Process Should You Learn First?

If you are starting from zero, the answer depends on what you plan to build.

Learn MIG first if you are doing automotive work, sheet metal fabrication, furniture, art, or general shop projects. The learning curve is shorter, the feedback from the puddle is immediate, and you will produce usable welds within your first few hours of practice. You will also develop good habits around settings and gun angle that transfer to other processes later.

Learn stick first if you are heading into construction, pipeline, maintenance, repair, or any field-work career. Stick equipment is portable, tolerant of imperfect fit-up, and forgiving of contaminated material. It also forces you to understand amperage, arc length, and electrode angle at a fundamental level — skills that make you a better welder in every process.

Learn TIG when you need precision on thin material, aluminum, stainless tube, or a code-controlled application. TIG is the most demanding process to master but it teaches puddle control better than anything else.

The honest professional answer is that all three matter. Cross-trained welders who can switch between processes are the ones who get hired and stay employed — a point we explore further in our look at whether welding is a good career.

Frequently Asked Questions

Which is stronger, arc welding or MIG welding?

Neither is inherently stronger. Both can produce welds meeting the same tensile requirements — commonly 70,000 psi for standard mild-steel consumables. Actual joint strength depends on penetration, fusion, joint design, base metal condition, and welder technique. Arc welding has an advantage on thick, dirty, or outdoor work; MIG has an advantage on thin material, clean metal, and repeatable production work.

Is a MIG weld stronger than a stick weld on the same material?

If both welds are made correctly to the same specification, their tensile strengths are effectively identical. Where MIG can appear weaker is on contaminated base metal, where trapped gas causes porosity. Where stick can appear weaker, it is usually due to slag inclusions or lack of fusion from improper technique. The consumable classification and the quality of execution determine the outcome.

Why do some people say stick welding is always stronger?

Experience bias and application bias. Stick welding has been the standard for heavy structural and field work for decades, and in those environments it genuinely outperforms gas-shielded MIG because of its tolerance for contamination and wind. When people generalize from that experience to “stick is always stronger,” they are usually forgetting about thin material, clean-shop production, and the fact that modern MIG procedures are code-qualified for the same structural applications.

Can MIG welding handle structural steel?

Yes. GMAW and FCAW are explicitly permitted under AWS D1.1 for structural steel when used with a qualified procedure. Many structural fabrication shops run exclusively MIG or flux-core on their production lines.

Which process produces deeper penetration?

Stick welding with a deep-penetrating electrode such as E6010 or E6011 typically achieves deeper root penetration than short-circuit MIG. Spray-transfer MIG and flux-core welding, however, can match or exceed stick penetration on thick plate when run at higher heat inputs. Penetration is a function of amperage, arc voltage, travel speed, and arc plasma characteristics — not the process name alone.

Is arc welding stronger than MIG for beginners?

Beginners usually achieve consistent results faster with MIG because the machine controls wire feed and shielding automatically. Stick welding requires the operator to manage arc length, electrode angle, and consumption rate simultaneously, which takes longer to develop. However, the skills learned from stick welding transfer well to every other process.

Does shielding gas make MIG weaker than flux-shielded stick?

No. Both shielding methods — external gas and flux-derived gas — serve the same purpose: preventing atmospheric contamination of the molten puddle. Each is effective when correctly applied. The weakness appears only when shielding is inadequate: wind blowing away MIG gas, or damp flux releasing hydrogen into a stick weld.

Which is more cost-effective for heavy fabrication?

For high-volume fabrication on clean material, MIG and flux-core usually win on total cost because of higher deposition rates and no rod changes. For field repair, small jobs, or situations with no power or gas supply, stick welding is more cost-effective because of minimal equipment and consumable expense.

Conclusion: The Right Process Is the One That Fits the Job

The question “is arc welding stronger than MIG?” assumes there is a single answer, and there is not. There is a right tool for each situation. On a rusty, wind-swept job site joining 3/8-inch plate, arc welding is the stronger choice because it will actually produce a sound weld in those conditions. On a clean shop floor joining 16-gauge tube, MIG is the stronger choice because it will produce a fused, low-distortion joint that stick welding cannot match on that material.

Tyler Marsh, from the story at the start of this article, eventually answered his customer by pulling out two test coupons he had welded months earlier — one stick, one MIG, both on the same batch of mild steel. He cut them, bent them, and showed the customer that neither one broke at the weld. The customer nodded, paid the invoice, and never asked again.

That is the real answer. When both processes are applied correctly, to the right material, with proper preparation and technique, they produce joints of equivalent strength. The difference is not in the ultimate tensile number — it is in which process lets you reach that number reliably in the conditions you are actually working in.

Choose based on your metal, your environment, and your code requirements. Master the settings, respect the preparation, and inspect your work. Do that, and the strength question takes care of itself.

References and Further Reading

• OSHA 29 CFR 1926.353 — Ventilation and protection in welding, cutting, and heating
• OSHA 29 CFR 1910.252 — General requirements for welding, cutting, and brazing
• OSHA 29 CFR 1910.253 — Welding, cutting, and brazing: specific requirements
• OSHA Safety and Health Topics: Welding, Cutting, and Brazing
• American Welding Society — standards, certifications, and technical resources
• AWS Catalog of Welding Standards
• TWI (The Welding Institute) — technical knowledge base on fusion welding processes

Deeper Dive: How Arc Physics Decides Strength

To understand why the two processes behave differently under the same thickness and joint, it helps to look at what is happening inside the arc itself. Both processes create an electric arc that melts metal, but the way they deliver energy to the workpiece is fundamentally different, and those differences explain most of the strength trade-offs discussed above.

Heat Distribution in the Arc Column

An arc is a column of ionized gas — plasma — carrying current from the electrode to the workpiece. The plasma temperature in the core of a welding arc can exceed 10,000°F, well above the melting point of any engineering metal. What matters for joint strength is how that heat is distributed when it lands on the plate.

Stick welding uses a relatively concentrated arc. The flux coating constrains the arc and directs it at the workpiece, producing a narrow, deep heat profile. This concentration is why a stick arc can cut through mill scale and sink into a root pass that a broader arc would only sit on top of. The trade-off is that the same concentration makes stick welding less forgiving on thin material — the heat has nowhere to spread before it burns through.

MIG welding in short-circuit transfer mode delivers heat in pulses — the wire touches the puddle, short-circuits, and clears hundreds of times per second. Each short circuit momentarily drops the arc voltage, which reduces the average heat input into the plate. This is the physics behind MIG’s advantage on sheet metal: the heat arrives in small, rapid installments rather than one continuous stream. Switch MIG into spray transfer mode, though, and the arc becomes continuous and the heat profile starts behaving much more like stick welding — deep, concentrated, and productive on thicker stock.

Cooling Rate and Metallurgy

After the arc passes, the weld pool solidifies and the surrounding metal undergoes a thermal cycle that determines its final microstructure. Cooling rate controls how coarse or fine the grain structure becomes, and grain structure controls mechanical properties: finer grains generally mean higher toughness, while very fast cooling can form hard, brittle phases in certain steels.

The slag blanket on a stick weld acts as insulation, slowing the cooling rate of the bead. That slower cooling typically produces a finer grain structure and better toughness in the deposited metal — one reason low-hydrogen stick electrodes are favored for critical structural and pressure applications. A MIG weld, with no slag blanket, cools faster in still air. On most carbon steel this difference is minor and within the range that the consumable classification already accounts for, but on alloy steels and on thick sections where hydrogen cracking is a risk, the slower cooling of a slag-covered weld can be a genuine advantage.

Preheat and post-weld heat treatment interact with both effects. Codes specify preheat temperatures based on carbon equivalent, thickness, and hydrogen risk — not based on process. Following the preheat table is one of the highest-leverage steps a welder can take to guarantee joint strength, whichever process is in use.

Deposition Efficiency

Deposition efficiency is the percentage of consumed filler metal that actually ends up in the weld versus what is lost to spatter, slag, or unused rod end.

• Stick welding typically runs 50–65% deposition efficiency with covered electrodes — the rest becomes slag, spatter, and the un-welded stub you must throw away.
• Solid-wire MIG runs 90–98% efficiency because almost all of the wire feeds directly into the puddle, with minimal spatter when settings are correct.
• Flux-core wire falls in between, roughly 75–85%, because the flux portion of the wire becomes slag rather than deposited metal.

This is not a strength measurement, but it explains the economics: MIG delivers more weld metal per pound of consumable purchased, which is why high-volume shops gravitate toward it even when either process would produce an acceptable joint.

Industry Perspective: Where Each Process Dominates

Looking at which processes industries actually choose reveals a practical map of where each one delivers the most value.

Construction and Structural Steel

Steel erection and heavy structural fabrication use a mix of FCAW and SMAW, with GMAW growing in shop-controlled environments. Field erection still leans heavily on stick welding because crews need portable equipment that tolerates wind, position, and imperfect fit-up. In the shop, flux-core has largely replaced stick for fillet welds because of its deposition rate.

Automotive and Transportation

Automobile bodies, frames, and trailers are overwhelmingly MIG-welded. Robotic MIG cells produce hundreds of identical welds per hour with consistent settings — something no manual process matches. The materials are clean, the fit-up is controlled, and the sheet is thin: exactly the conditions where MIG’s advantages are strongest.

Pipeline

Long-distance pipeline construction remains a stronghold for stick welding, particularly E6010 root passes followed by E7010 or E8010 fill and cap. Automated GMAW systems have made inroads in shop-based spool fabrication, but the field is still dominated by stick because of portability and positional capability.

Shipbuilding and Heavy Equipment

Shipyards use large amounts of FCAW and GMAW for hull fabrication, where flat-panel production and high deposition rates matter enormously. Heavy equipment manufacturers similarly run automated and semi-automatic MIG cells for chassis and structural components, supplementing with stick for repair and field service work.

Repair and Maintenance

The repair sector — farms, mobile welders, pipeline maintenance, industrial service — is stick welding’s home territory. The jobs are unpredictable, the material condition is inconsistent, and the power and gas supply may be limited. A stick welder and a box of rods will handle situations that would send a MIG operator back to the shop for a grinder and a gas bottle.

Decision Cheat Sheet

Print this out, tape it to your machine, and use it as a starting point. As your experience grows, you will learn when to deviate from it — but for the vast majority of everyday jobs, this table points at the right process.

Final Thought: Skill Translates, Machines Do Not

The welders who last in this trade are not the ones who argue about which machine is better. They are the ones who understand what each process does to the metal and choose accordingly. A journeyman who can run a clean 7018 vertical-up and dial in a pulsed-MIG program on aluminum is worth more than a specialist who can only do one or the other.

Whatever process you start with, learn to read the puddle, understand your amperage and voltage, respect the preparation, and hold yourself to the same inspection standard you would apply to someone else’s work. Strength in welding is not a property of the process. It is a property of the welder.