4 Types of Welding Processes: MIG, TIG, Stick & Flux-Core

A farmer’s chopper blower band snaps on a Saturday, with the nearest replacement two days away — so he wheels out a wire welder, tacks the thin steel back together and saves the harvest. That single repair shows why knowing the four main welding processes matters: pick the wrong one and you burn a hole through the part, pick the right one and the job is finished before lunch.

Why the Four Arc Welding Processes Matter (and What They Are)

Saturday morning, a farmer’s chopper blower band snaps clean in half. The nearest replacement is two days out, and two days means the harvest waits. So he wheels out the wire welder in the corner of the barn, tacks the thin steel back together, and the machine is cutting again before lunch. Nothing about that repair required a six-figure robotic cell or a metallurgy degree. It required knowing which welding process fits the job in front of you.

That is the real question behind this article, so let’s answer it immediately. The four types of welding processes taught in schools and used across industry are:

• SMAW — Shielded Metal Arc Welding, commonly called stick welding
• GMAW — Gas Metal Arc Welding, commonly called MIG welding
• GTAW — Gas Tungsten Arc Welding, commonly called TIG welding
• FCAW — Flux-Cored Arc Welding, often just called flux-core

All four are arc welding processes. All four melt metal with an electric arc to fuse a joint. Beyond that shared physics, they behave like four different tools with four different personalities, and the rest of this article breaks down how each one works, what it costs, where it shines, and where it fails.

What Welding Actually Is (According to the AWS)

The American Welding Society defines welding as a joining process that produces coalescence of materials by heating them to the welding temperature, with or without pressure and with or without filler metal. That wording matters. Heat is mandatory. Pressure and filler metal are optional — which is why a TIG weld on a watch case and a stick weld on a bridge girder are both legitimately called welding.

Welding is bigger than arc processes. The AWS recognizes 11 major categories of welding, cutting, and allied processes, covering everything from oxyfuel flame cutting to electron beam and laser processes. If you are curious about the higher-tech end of that spectrum, our Alpha Laser Welding: Systems, Uses, and Safety Guide walks through one of them. But for the work most people actually encounter — farm repair, structural steel, fabrication shops, automotive, pipe — arc welding dominates, and those four processes above are the ones textbooks and shop training programs group together every time.

Standard AWS Designations vs. Shop Slang

Every process carries two names, and knowing both keeps you from getting lost in job listings, machine manuals, and trade conversations.

Slang travels faster than standards, but standards travel further. A job posting asking for a GTAW-certified pipe welder is not being precious; it is being precise, because Aerospace TIG Welding: Standards, Techniques, and Training demands a level of control that stick welding simply cannot deliver on thin, critical material.

Why Learning These Four Is Worth Your Time

The workforce numbers explain it better than any pep talk. The U.S. Bureau of Labor Statistics reports roughly 437,700 welder jobs nationwide with a median annual wage of about $53,750, and welding roles are projected to keep growing alongside infrastructure, energy, and manufacturing demand. At the same time, the American Welding Society projects that 320,500 new welding professionals will be needed in the U.S. by 2029 — close to 80,000 new hires every year to replace retirements and fill expansion.

Those figures come from the BLS Occupational Outlook Handbook and AWS workforce data, with the shortage discussed further in Where Are the Welders? from the Welding Digest. The gap is real, and it rewards people who can do more than one thing well.

What This Article Covers

From here, we work from shared fundamentals outward. Section two explains the physics all four processes share: the arc, shielding, polarity, metal transfer, and duty cycle. Then each process gets a full deep dive — stick welding’s go-anywhere ruggedness, MIG’s speed and ease, TIG’s precision, and flux-core’s heavy deposition — followed by a side-by-side comparison, a decision framework for picking one, safety and ventilation essentials, and a realistic learning path from beginner to multi-process capable.

Whether you are a hobbyist choosing a first machine or a shop owner cross-training staff, the goal is the same as that farmer’s: pick the right process, and the job is finished before lunch.

How Arc Welding Actually Works: Core Concepts Explained

Before you pick between MIG, TIG, stick and flux-core, understand that all four are variations on one idea. Strip away the gas bottles, wire spools and electrode holders, and every arc process boils down to the same thing: an electric arc that melts metal so two pieces fuse into one.

The Arc: One Heat Source, Four Flavors

When an electrode comes close to the workpiece (or touches it and is pulled back), current jumps the gap and forms an arc — a plasma stream that runs hotter than the melting point of steel. The arc melts both the base metal and the electrode; once the puddle solidifies, the metals are joined. That single sentence describes stick, MIG, TIG and flux-core equally well. The differences come down to what the electrode is made of, how the molten puddle is protected from the atmosphere, and how the filler metal reaches the joint.

Consumable vs. Non-Consumable Electrodes

A consumable electrode does double duty: it carries the current and melts into the weld as filler. Stick rods, MIG wire and flux-cored wire are all consumable, which is why stick and MIG can fill a joint quickly — the filler lands right where the heat is.

A non-consumable electrode holds the arc but doesn’t melt into the pool. GTAW uses tungsten, which resists melting at arc temperatures, and the welder feeds a separate filler rod by hand. That extra step makes TIG slower, but it also gives you precise control over exactly how much metal goes into the joint and exactly where the heat goes.

Why Shielding Matters

Molten steel will grab nitrogen and oxygen from the air almost instantly, producing porosity, brittleness and a weak weld. Shielding keeps the atmosphere off the puddle, and the four processes do it three different ways:

• External shielding gas — MIG and gas-shielded flux-core blow argon, CO₂ or blends over the arc from the gun nozzle.
• Flux — stick coatings and flux-cored wire contain minerals that decompose in the arc, releasing shielding gas and forming a protective layer of slag over the cooling puddle.
• Inert gas around hot tungsten — TIG blankets the arc in pure argon or an argon-helium mix, which is why TIG welds come out clean and slag-free.

Slag is a mixed blessing: it protects the weld as it cools, but someone has to chip and brush it off afterward.

Polarity: AC, DCEN and DCEP

Which way current flows changes how deeply the arc digs in. With DCEP (direct current electrode positive), most arc energy strikes the workpiece, giving deeper penetration — the default for stick and short-circuit MIG. With DCEN (electrode negative), more heat stays at the electrode, which suits TIG on thick material and certain flux-cored applications. AC alternates direction; on aluminum, it also strips the oxide layer off the surface as it welds. Getting polarity backwards is one of the most common beginner mistakes, and it usually shows up as poor penetration or a wandering arc.

Metal Transfer Modes in GMAW

MIG is the only arc process with real tuning knobs for how the wire crosses the arc gap:

• Short-circuiting — the wire touches the puddle, shorts out, melts off and repeats many times per second. Low heat, great for thin sheet.
• Globular — large droplets transfer across the gap. Cheap and dirty, but messy with spatter.
• Spray — a fine stream of droplets sprays across the arc at high current. Deep penetration, smooth bead, no spatter, flat positions only.
• Pulsed-spray — the power source alternates between a peak current that pinches off one droplet and a background current that holds the arc. Spray-like quality at lower average heat.

Understanding these modes is what lets a MIG welder run 24-gauge sheet and half-inch plate off the same wire spool.

Penetration vs. Deposition

Penetration is how deep fusion goes into the base metal; deposition is how much filler metal piles up per minute. Spray-transfer MIG and TIG penetrate deep, while high-deposition processes like flux-core build weld volume fast. Structural joints need both — a fat bead sitting on top of the plate with no fusion underneath is a reject.

Welding Positions

Position names matter when you’re reading a procedure or buying rod. Flat (1G/1F) is easiest — gravity works with you. Horizontal, vertical and overhead get progressively harder, because you’re fighting gravity with a liquid puddle. Some consumables are “all-position” rated; others, like spray-transfer MIG, are effectively flat-and-horizontal only.

Duty Cycle: The 10-Minute Rule

Every welder has a duty cycle — the minutes out of a 10-minute cycle it can run at rated output before cooling. A unit rated 160 A / 60% runs 6 minutes, then cools 4. Ignore it and you’ll overheat mid-job. Small hobby machines often carry 20–30% duty cycles, while industrial shop machines run 60–100%.

One more thing separates the processes in daily practice: ultraviolet output. OSHA notes that inert-gas metal-arc welding produces UV radiation 5 to 30 times that of shielded metal-arc welding, which is why TIG demands just as much skin and eye protection as stick — even with zero spatter. If you’re moving into aluminum work, our Aluminum MIG Welding: The Complete Practical Guide picks up where these basics leave off.

You now have the vocabulary — electrodes, shielding, polarity, transfer modes, position and duty cycle — to understand exactly what each of the four processes does differently. That’s where we turn next.

Type 1: Shielded Metal Arc Welding (SMAW / Stick)

If you have ever watched someone weld in a gravel driveway, a ditch, or a farmyard on a windy day, you were watching Shielded Metal Arc Welding. Shop slang calls it stick welding, rod welding, or simply “stick.” It is the oldest of the four processes we cover, still one of the most widely taught, and the one that shows up wherever conditions are less than ideal.

How the Flux Coating Does the Work

What sets stick welding apart from a plain electrical arc is the electrode itself. A stick electrode is a metal rod, usually a mild or low-alloy steel core, wrapped in a chemical coating called flux. Strike the arc and the coating does not sit passively; it disintegrates in the heat, breaking down into a blanket of shielding vapors that surrounds the molten weld pool and keeps atmospheric oxygen and nitrogen from contaminating it. The flux also yields a layer of slag that floats on the cooling bead and shields it as it solidifies. One consumable rod delivers filler metal, shielding, and post-weld protection all at once.

That built-in shielding is why stick electrodes are described as self-shielding. There is no gas bottle to drag along, no hose to snag, and no gas stream for the wind to blow away. The rod shields itself.

Equipment and Polarity

The equipment list is refreshingly short: a constant-current power source, an electrode holder (the “stinger”), a ground clamp, a chipping hammer and wire brush, and a box of rods. Machines can be dedicated stick units or multi-process welders that also run aluminum flux core welding wire from the same box.

Polarity matters more here than many beginners realize. On AC, the current alternates direction and the arc is serviceable but harsher. On DC reverse polarity (DCEP), where the electrode is positive, you get easier arc starts, fewer arc outages, noticeably less spatter, and smoother out-of-position welding. If your machine offers a polarity switch, DCEP is where most common 6010, 6011, 6013 and 7018 electrodes prefer to run.

Where Stick Welding Shines

• Outdoors and in drafts. Because the electrode shields itself, SMAW holds up in wind that would blow away the shielding gas from a MIG or TIG arc. For farm and field repair this is the deciding factor, a recurring theme in OSU Extension’s welding-on-the-farm guidance.
• Dirty, rusty, or painted metal. Certain rods are formulated to burn through mill scale and surface contamination rather than refuse to start.
• Hardfacing and maintenance. Overlaying wear-resistant alloy onto bucket teeth, augers, and plow points is classic stick territory, and the range of alloy steel welding electrodes exists mostly for this kind of work.
• Out-of-position work. Overhead, vertical-up, and ceiling work where a wire feeder would fight gravity. The all position welding rod guide matches electrodes to each position.
• Thick sections and root passes. SMAW gives excellent penetration and bridges gaps and poor fit-up that would defeat a wire process.
• Portability. One small machine and a handful of rods fit in a truck bed for field repairs far from an outlet.

The Honest Drawbacks

Stick welding is neither the fastest nor the easiest process. Every few inches the rod is consumed, so welding stops, the holder is reloaded, and the arc is restarted. That stop-start rhythm makes it slower than MIG, which can run up to four times faster on comparable work. Slag has to be chipped and brushed off every pass, and spatter and porosity are more common while you are still learning rod angle, arc length, and travel speed.

Then there is waste. Roughly 50 lb of stick electrodes yields about 30 lb of deposited metal, because the flux coating turns to gas and slag. MIG wire, by comparison, delivers close to 49 lb out of the same 50 lb. The stub end left in the holder is scrapped too.

Thin material is the real trap. Welding 18-gauge sheet with a stick rod is a fast route to burn-through: heat input is high and the arc is hard to feather down. On anything thinner than about 1/8 inch, most welders switch to MIG or TIG.

Electrode size	Typical amperage	Common use
1/16 in (1.6 mm)	20–40 A	Thin sheet, tack welds
3/32 in (2.4 mm)	40–90 A	Light fabrication, all positions
1/8 in (3.2 mm)	75–130 A	General shop and farm work
5/32 in (4.0 mm)	110–170 A	Structural, heavier plate
3/16 in (4.8 mm)	140–220 A	Heavy plate, root and gap filling

Real-World Applications

You will find SMAW on structural steel skeletons, pressure piping, bridge and building fabrication, shipyards, water towers, maintenance departments, and every farm shop that has ever fixed a broken hitch. It repairs broken equipment two days before harvest, and it remains the standard fallback whenever the wind is blowing, the extension cord is 100 feet long, or the metal has not been cleaned in years.

For all its age, stick welding earns its place first in this article: it is the process that works when nothing else will. Learn it after MIG, and you will have a skill that travels anywhere.

Type 2: Gas Metal Arc Welding (GMAW / MIG)

Gas Metal Arc Welding carries the AWS designation GMAW, but nearly every shop knows it as MIG, short for metal inert gas. Rather than swapping electrodes like stick welding, MIG feeds a continuous consumable wire through the welding gun while a flow of shielding gas protects the puddle. The result is a process that can cover a lot of ground with far less downtime.

How It Works

MIG machines use a constant-voltage power source. Instead of holding current steady, voltage stays constant while amperage adjusts to arc length. If the gun drifts too far from the joint, the machine pushes more amperage into the arc to compensate. This self-correcting behavior is a large part of what makes the process so forgiving for beginners.

A spool of wire is pushed by drive rolls through a liner and out the contact tip at a set speed. The wire contacts the work, forms a short circuit, melts off, and becomes filler metal. At the same time, shielding gas is drawn from a cylinder, regulated down to a few cubic feet per hour, and blown over the puddle to block oxygen and nitrogen.

Shielding Gas Selection

The gas you run has a direct impact on arc quality. The most common choices for GMAW are:

• 75% argon / 25% CO₂ – The go-to for mild steel. Offers a smooth arc, low spatter, good penetration, and easy starts.
• 100% CO₂ – Cheaper with deeper penetration, but creates noticeably more spatter and a rougher bead. Often used for high-volume production.
• 100% argon – Required for aluminum. CO₂ will break down and contaminate an aluminum weld.
• Argon/CO₂ blends with low CO₂ or oxygen – Used for stainless steel to limit carbon pickup and keep the bead clean.

For help deciding on cylinder sizes or regulator setups, our Airgas welding supplies guide can help narrow down the options.

Metal Transfer Modes

How metal crosses the arc depends on the settings, and each transfer mode serves a specific purpose:

1. Short-circuit transfer – The wire touches the puddle dozens of times per second, depositing small droplets. This runs the coolest and is best for thin metal and out-of-position work.
2. Globular transfer – Large, irregular droplets with higher spatter. Cheap on gas, but rarely optimal for quality welds.
3. Spray transfer – A fine, stable stream of droplets at higher voltage and heat. Great for flat fillet welds on thicker plate.
4. Pulsed-spray transfer – Pulses of current create spray transfer at a lower average heat. This allows spray-like results in positions that would be difficult at steady spray settings.

Speed, Efficiency, and Material Range

MIG is built for production. It can run up to four times faster than stick welding due to its continuous wire feed and lack of slag to chip between passes. It’s also highly efficient: 50 lb of MIG wire produces about 49 lb of deposited metal (roughly 98%), compared to stick welding where 50 lb of rods yields only around 30 lb in the joint.

It handles 24-gauge sheet and up across carbon steel, stainless steel, and aluminum. Most shop machines are comfortable to about 3/8 in. plate, with heavier sections often going to flux-core or stick. As noted by OSU Extension’s welding on the farm publication, wire welding is often the practical default for maintenance repairs where speed matters.

Welding Aluminum With MIG

Aluminum is the pickiest application for GMAW. The soft wire is prone to buckling in long liners, so most welders use a spool gun at the trigger or a parallel liner through the cable. Prep is just as critical: aluminum’s oxide layer melts around 3,700°F while the base metal melts near 1,220°F, so it must be chemically or mechanically cleaned immediately before welding. For specifics, see our aluminum cleaner for welding guide and aluminum MIG welding guide.

Cost Profile

MIG is often the cheapest way to get into arc welding. Machines are widely available used, setup takes minutes, and the learning curve is short. However, running costs add up: shielding gas is a recurring expense, and contact tips and drive rolls need replacing over time. If gas isn’t an option, flux-cored wire can fill the gap. Our aluminum flux core welding guide breaks down where self-shielded wire can work and where it falls short.

For automotive panels, farm repairs, sheet metal, and first-time learners, MIG strikes one of the best balances of speed, versatility, and usability in the shop.

Type 3: Gas Tungsten Arc Welding (GTAW / TIG)

If stick and MIG welding are about melting filler metal into a joint as fast as the puddle will take it, GTAW is the opposite philosophy. Gas tungsten arc welding, which almost every shop calls TIG, uses a non-consumable tungsten electrode to create the arc. The tungsten gets hot enough to melt the base metal but does not melt away itself. Filler rod, when the joint actually needs any, is fed separately by hand into the puddle. That single design difference is what gives TIG its reputation for control.

How the TIG Torch Works

A TIG torch holds a pointed tungsten electrode surrounded by a ceramic cup. Inert shielding gas, usually pure argon, flows through the cup and blankets the arc and the puddle from oxygen and nitrogen in the air. One cylinder of argon handles steel, stainless and aluminum, which keeps gas logistics simple even though everything else about the process takes more setup.

The power source is a constant-current machine rather than the constant-voltage design used for MIG. Arc amperage is set on the machine, then fine-tuned on the fly by the operator using a foot pedal or, on smaller torches, a hand control. That real-time heat control is the reason a TIG welder can hold a puddle on 0.040-inch tubing without blowing through, then step on the pedal to sink a root pass into thicker material a moment later. Most modern TIG machines strike the arc with high frequency, so the tungsten never has to touch the work and contaminate the weld.

Many TIG welds are autogenous, meaning the two edges of the joint are simply melted together with no filler added at all. Add rod only where a gap or fillet calls for it. The result is a weld with no spatter, minimal heat tint, and the even, stacked-ripple appearance welders are judged on in code work.

AC vs. DC: Why Aluminum Needs Alternating Current

On steel, stainless, copper and titanium, TIG runs on DC electrode negative, which puts about two-thirds of the heat into the workpiece and keeps the tungsten cool. Aluminum changes the equation because of that stubborn oxide layer. Running AC alternates the polarity many times per second, and the electrode-positive half of the cycle blasts the oxide off the surface while the electrode-negative half drives penetration into the joint. The characteristic crackling sound of AC TIG on aluminum is that cleaning action happening in real time. Helium can be blended with argon when deeper penetration on thick aluminum is needed, but pure argon remains the standard.

The Quality, Speed and Skill Trade-Off

The industry comparison chart published by Ohio State University’s extension program rates GTAW as “very slow” in speed and “most skill” required, and it carries the highest purchase cost and highest operating cost of the four processes. All three ratings are honest. One hand holds the torch, the other feeds filler rod, and the foot regulates heat, so the operator is coordinating three motions at once while watching a puddle the size of a match head.

What you buy with that effort is capability nothing else matches:

• Weldability down to about .010 inch of material thickness with precise heat control.
• Every weldable metal: carbon steel, stainless, aluminum, magnesium, titanium, copper alloys and exotic refractory metals.
• All welding positions, from flat to overhead.
• No spatter to grind off and no slag to chip, so post-weld cleanup is mostly a wire brush.
• The highest quality and most aesthetically consistent beads of any arc process.

Where TIG Welding Earns Its Keep

TIG is the default in industries where the weld is inspected as carefully as the part is machined: aerospace structures and components, hydraulic tubing, power-plant and nuclear piping, food-grade and pharmaceutical stainless systems, chemical processing lines, and exotic-alloy fabrication. The same control makes it the process of choice for thin-wall stainless pipe, bicycle and motorcycle frames, turbine repair, and visible architectural work where appearance is part of the specification. Preparation matters more here than anywhere else, so it pays to learn proper aluminum cleaning and pre-weld prep before attempting critical joints.

The costs are real, too. TIG machines sit at the top of the price range, tungsten electrodes and collets are ongoing consumables, and travel speeds are the slowest of the four processes, which means labor, not materials, drives the invoice. That is why shops rarely use TIG where a faster process would satisfy the drawing, and why many pair a TIG machine with a stick or MIG unit rather than running TIG on everything.

Type 4: Flux-Cored Arc Welding (FCAW)

Flux-cored arc welding is what you get when someone looks at stick welding’s shielding slag and asks whether it could be baked into a wire. Instead of a solid rod or a bare wire spool, FCAW feeds a hollow tubular electrode — a thin steel sheath rolled into a tube and packed with mineral flux and metal powder — through the same kind of gun a MIG welder uses. As the arc melts the tube, the flux core does two jobs at once: it breaks down into a shielding gas that wraps the arc, and it leaves a slag covering that keeps air away from the pool while the weld cools. That double duty is the whole trick of the process.

Self-Shielded vs. Gas-Shielded: Two Flavors of Wire

FCAW actually comes in two variants, and confusing them is one of the most common shop mistakes:

• FCAW-S (self-shielded): No external gas bottle at all. The flux core generates the entire shield, so all you need is the wire feeder. Because nothing depends on a gas envelope holding still, it is far less affected by drafts than MIG, which makes it the go-to process for outdoor and field work.
• FCAW-G (gas-shielded): Uses an external shielding gas — typically CO₂ or an argon/CO₂ mix — in addition to the flux core. The added gas gives cleaner arc behavior and tougher weld metal, at the cost of a bottle you have to drag around.

Both types run on a constant-voltage power source with a wire feeder, which is why Aluminum Flux Core Welding: What Actually Works in 2026 notes that the same machine often handles both MIG and flux-cored wire — swap the spool, change the polarity or settings, and go. More on that shared hardware in the comparison section.

Why Fabricators Love It: Penetration, Deposition and Forgiveness

Flux-cored wire is a productivity tool first. It deposits roughly two to three times the metal of stick welding in the same amount of time, which is exactly why hardfacing work — rebuilding a loader bucket edge, a plow share, a crusher tooth — almost always runs on flux-cored wire. Where stick welders lay down a bead, flux-cored machines pile on metal. It also achieves deep penetration on heavier sections; the process is generally rated for 1/8 in. material and up, and it copes with rusty or lightly dirty steel better than short-circuit MIG, since the flux chemistry is designed to burn contaminants out of the puddle.

Where It Shines

You will find FCAW wherever steel is thick, schedules are tight, and the work happens outside a climate-controlled shop:

• Structural steel and heavy plate fabrication
• Shipbuilding and offshore work
• Field erection and construction welding
• Hardfacing and repair on earthmoving and farm equipment
• Heavy equipment and pressure vessel shops

It handles all-position work when you select an all-position wire classification, and its deep penetration makes out-of-position welds on medium plate practical. For filler metal selection advice on tougher base metals, our Alloy Steel Welding Electrodes: Selection, Use & Safety guide covers the classification system in depth.

The Trade-Offs Nobody Mentions in the Sales Pitch

Flux-cored welding earns its reputation honestly, but the drawbacks are real:

• Fumes and smoke. The flux that shields the arc also generates noticeably more particulate than solid-wire MIG. Studies show total particulate exposure is higher when flux-cored consumables are used, so ventilation and fume extraction are not optional — OSHA’s welding, cutting and brazing hazards guidance treats fume control as a core requirement of the work.
• Slag cleanup. Yes, there is slag — just like stick. It chips off more easily than SMAW slag, but it still has to come off, and it hides defects until you chip it.
• Spatter. Expect more cleanup than solid-wire MIG, particularly with self-shielded wires and incorrect voltage settings.
• Cost per pound. Tubular wire costs more than solid wire, and gas-shielded variants add cylinder rental. The deposition rate usually justifies it on heavy work, but on thin, light fabrication it is overkill.

How It Fits Your Setup

The practical advantage of FCAW is that it reuses MIG hardware. If you own a quality wire-feed machine with gas capability, you likely already own a flux-cored welder — you just need the right spool, the correct polarity (most self-shielded wires run DCEP, but check the datasheet), and gas only if the wire calls for it. That low barrier to entry, combined with unmatched deposition and genuine outdoor toughness, is why flux-cored arc welding sits alongside MIG, TIG and stick as one of the four processes every welder is expected to know.

Side-by-Side Comparison of the 4 Welding Processes

Knowing how each process works is one thing; knowing which one to reach for when the clock is running is another. The whole decision compresses into five points: the metal, its thickness, where you are standing when you strike the arc, how fast the job must move, and what you will spend on a machine and on filler metal. Ohio State University’s extension program packs those trade-offs into one clean chart in its Welding on the Farm guide, and it lines up closely with what shops see every day.

Speed and Skill: The Two Axes That Matter Most

Start with speed. OSU rates gas metal arc welding and flux-cored arc welding as very fast, shielded metal arc welding as slow, and gas tungsten arc welding as very slow. That is a statement about deposition rate and travel speed, not an insult. A MIG gun feeds wire continuously, so the arc never pauses while you swap rods. A TIG operator is coordinating a torch in one hand, a filler rod in the other, and often a foot pedal, all while running lower amperage than the other processes would use for the same joint.

Skill follows the same gradient, and OSU puts it plainly: MIG needs some skill, stick needs more skill, and TIG needs most skill. Flux-cored sits close to MIG on the learning curve, since both use the same wire-feed mechanics. A beginner can lay a respectable MIG bead in an afternoon. A beginner’s first stick welds stick to the plate, crater, and spatter. A beginner’s first TIG attempts usually look like a row of tic-tacs. That progression is exactly why most training programs teach wire feed first, then stick, then TIG, a path we cover in more detail in our aluminium welding course overview.

Cost: Purchase Price vs. Cost per Pound of Weld

Purchase cost and operating cost rarely point the same direction. Stick machines are the cheapest to buy and among the most expensive to run, because roughly 40 percent of every rod ends up as stub and slag. TIG machines cost the most upfront and stay expensive to operate, thanks to tungsten electrodes, argon gas, and slow travel. MIG and flux-cored land in the moderate purchase range and the lowest operating range, and that ranking holds steady across price tiers. The exact numbers shift by brand and duty cycle, but the order does not.

The Full Comparison Table

Factor	SMAW (Stick)	GMAW (MIG)	GTAW (TIG)	FCAW (Flux-Cored)
Metals weldable	Steel, stainless, some alloys	Carbon steel, stainless, aluminum	All weldable metals	Steel and stainless
Minimum thickness	1/8 in. and up	24 gauge and up	22 gauge and up (down to about .010 in.)	1/8 in. and up
Speed	Slow	Very fast	Very slow	Very fast
Skill required	More skill	Some skill	Most skill	Some skill
Purchase cost	Low	Moderate	High	Moderate
Operating cost	High	Low	High	Low
Portability	Excellent	Good (machine plus gas bottle)	Fair (machine, cooler, bottle)	Good (excellent self-shielded)
Outdoor use	Excellent	Poor with gas; fair self-shielded	Poor (argon shields poorly in wind)	Excellent (self-shielded grades)
Deposition efficiency	About 60% (50 lb rod yields ~30 lb)	About 98% (50 lb wire yields ~49 lb)	Filler added separately, minimal loss	Two to three times stick’s deposition
Welding positions	All positions with the right rod	Flat and horizontal easiest; all-position wire exists	All positions, with the most control	Flat and horizontal preferred; all-position wire available
Typical industries	Construction, pipelines, repair, hardfacing	Auto fabrication, sheet metal, manufacturing	Aerospace, food-grade piping, exotic alloys	Structural steel, shipbuilding, heavy plate

Read down the thickness row and the pattern becomes obvious. MIG opens the door to the thinnest sheet, TIG is right behind it with the added bonus of working on aerospace-grade materials, and stick and flux-cored both bottom out around 1/8 inch. That is why thin automotive panels push you toward aluminum MIG work or TIG, while heavy structural plate pushes you toward flux-cored. For a fuller treatment of rod selection across joint types, see our all-position welding rod guide.

Machine Overlap: What You Are Really Buying

The practical upshot: three machines can cover four processes. A 200-amp multiprocess MIG/TIG/Stick unit handles light fabrication, thin sheet, and general repair, while a dedicated heavy wire-feed machine covers thick structural work outdoors. Welders who understand the advantages of stick welding tend to keep one around anyway, because on a windy jobsite nothing else is that simple.

Match the process to the metal, the thickness, and the weather, and the rest of the decision takes care of itself. The next section turns that logic into a step-by-step framework with real project scenarios.

How to Choose the Right Welding Process for the Job

Here is the part glossy brochures rarely admit: no welding process suits every job. Stick shrugs off wind, rust and rain but makes a hash of clean sheet metal. TIG turns out jewel-smooth welds at a fraction of a wire feeder’s speed. Every process is a trade-off; choosing well means knowing which trade you will accept.

The Seven Questions That Decide the Job

Run this checklist before you strike an arc. Each answer narrows the field.

• What metal is it? Carbon steel forgives almost anything. Aluminum, stainless and exotic alloys do not.
• How thick? Twenty-two gauge sheet and 1-inch plate belong to different processes.
• Where are you welding? A shop keeps every option open; a windy field rules out bottled gas unless shielding is in the wire.
• What position? Flat-only work is easy; overhead and vertical-up demand the right electrode and transfer mode.
• What finish does it need? A visible cosmetic weld differs from a buried structural joint.
• What is the budget? Machine price plus consumable cost per hour.
• What can you actually run today? Be honest about skill. An untrained hand on a TIG torch makes scrap, not heirlooms.

Seven Real Jobs, Mapped to a Process

The job	First choice	Why
Farm sheet-metal repair, up to 3/16 in.	MIG	Fast, low heat on thin steel
Structural steel outdoors	Self-shielded flux-core or stick	Works when wind kills a gas shield
Aluminum boat trailer	MIG with spool gun (AC TIG for show welds)	Heat control and clean filler
Food-grade stainless piping	TIG with argon purge	Purest, most corrosion-resistant joint
Hardfacing a bucket	Stick or flux-core	High deposition, rods everywhere
Automotive bodywork	Short-circuit MIG	Fine control, minimal warping
Thick plate in a shop	Spray-transfer MIG or gas-shielded flux-core	Deep penetration, fast fill

Farm and light repair. The work is thin, the location moves, the metal is rarely clean. Ohio State Extension sizes it: light repair from sheet up to 3/16 in. steel suits a 130- to 150-amp MIG unit at a 30% duty cycle, while trailer hitches, axles and hardfacing call for a 200- to 250-amp MIG machine at 40 to 60% duty cycle or a 175- to 250-amp stick welder (OSU Extension, Welding on the Farm). In a breeze, stick stays the field champion; our advantages of stick welding guide explains why.

Structural steel outdoors. Self-shielded flux-core or stick keeps working when wind scatters an argon shield. On positional structures, a 6010 root over a 7018 cap is standard; the all position welding rod guide covers electrode selection and settings.

An aluminum boat trailer. Aluminum sheds heat fast and grows an oxide layer that melts far hotter than the metal beneath it, so prep decides success before the arc starts; aluminum cleaner for welding shows the routine. Then run 100% argon through a spool gun; aluminum MIG welding covers settings, while aluminum boat welding covers hull-grade joint design.

Food-grade stainless piping. TIG is the only sensible answer. Run DCEN with argon and purge the pipe interior so the root does not sugar, and match the filler metal to the alloy; alloy 20 welding procedures show how corrosion-resistant alloys are joined properly.

Hardfacing a bucket or blade. Skip precision entirely. Stick or flux-core delivers the heavy, high-deposition bead you need, and alloy steel welding electrodes covers choosing a rod for abrasion versus impact wear.

Automotive bodywork. Thin steel wants short-circuit MIG on fine wire, around .023 in., at low amperage to avoid warping panels. Bent alloy wheels are a specialty of their own: read alloy wheel welding first.

Thick plate in a shop. Spray-transfer MIG or gas-shielded flux-core gives deep penetration and fast fill. Set the root pass correctly the first time.

Versatility, Entry Cost and Gas Bottles

Budget shapes the choice as much as physics does. Basic stick welders cost a few hundred dollars and weld dirty steel all day; a quality wire welder runs roughly $450 to $2,000, and that difference buys convenience, speed and a flatter learning curve.

Buy for versatility. MIG and flux-cored usually share one machine: swap the wire spool, change the gas, or turn the gas off entirely for self-shielded flux-core. TIG machines commonly include a stick function as well. Gas adds logistics, since cylinders must be bought or rented, refilled and exchanged; Airgas welding supplies breaks down what bottles and regulators actually cost.

Two machines earn their keep in two situations: a spool gun swapped weekly justifies a dedicated aluminum unit, and when you work in the field, a cheap stick machine in the truck keeps your wire welder clean in the shop.

Run the seven questions against your actual job, not your aspiration. The wrong process never forgives a bad choice; the right one makes you look more skilled than you are.

Safety, Fumes, Ventilation and Certification Essentials

All four processes share the same three immediate physical hazards: blinding ultraviolet and infrared radiation, molten metal spatter, and an energized circuit that can kill you as easily as it melts steel. Each also adds a chemical hazard that takes years to appear. OSHA’s welding hazards guidance separates health hazards (fumes, metal oxides, UV, noise) from safety hazards (burns, eye damage and electrical shock). A stick rod stuck to the work or an arc struck without eye protection injures in under a second; respiratory damage takes years. Both are worth your attention.

What Is Actually in Welding Fume

Welding fume is not one substance. It is a suspension of ultrafine metal oxides shed from the consumable and the base metal, plus gases from flux decomposition and shielding gas breakdown, and its makeup depends entirely on the metal under the arc. Mild steel gives you iron oxide and manganese. Stainless and many alloys give you hexavalent chromium, Cr(VI). Galvanized coatings give you zinc oxide, the cause of classic metal fume fever chills. Painted or plated metal can release lead or cadmium, which is why coatings should be stripped rather than simply welded over.

Manganese and hexavalent chromium deserve specific attention. OSHA sets a permissible exposure limit for Cr(VI) of 5 µg/m³ as an 8-hour time-weighted average under 29 CFR 1910.1026, a number tight enough that welding stainless without ventilation exceeds it within minutes. NIOSH reports that welders carry a 40% increase in relative risk of developing lung cancer, a figure driven largely by those two exposures rather than by the arc itself.

The environment changes the number dramatically. A field study of 2,065 particulate measurements across welding operations found that total exposure was 67% higher in enclosed spaces and 43% lower when local exhaust ventilation (LEV) was in use. Manganese was even more sensitive: 750% higher in enclosed spaces and 67% lower with LEV. Welding inside a tank, a cab or a shop bay with the doors shut is not a badge of toughness. It is the single worst thing you can do for your lungs, and the study, published in the Annals of Occupational Hygiene, is the most useful number in this section.

Process-by-Process Safety Differences

The four processes are not equally dirty. Stick welding produces the most smoke and fume per hour of arc time, because the entire flux coating burns. Flux-cored wire runs a close second, and self-shielded FCAW-S in particular generates heavy fume that needs real airflow to clear. MIG is comparatively clean, with argon-rich mixes producing less smoke than CO2-heavy mixes. TIG is the cleanest of all, which is one reason it dominates food-grade and aerospace shops. Even on TIG, the arc still puts out enough UV to sunburn skin and burn eyes in seconds, so a curtain or screen protects everyone in the shop, not just the welder.

Fume extraction gear has improved: a welding supply guide covering gases and safety equipment walks through arm-mounted extractors, bench downdraft tables and ceiling hoods. Filters matter too — a P100 or half-face respirator with appropriate cartridges is a shop necessity for confined or poorly ventilated work, not a nice-to-have. Low-manganese and low-alloy electrodes also exist for shops with exposure limits to hit; our alloy steel electrode selection guide covers how filler choice interacts with both metallurgy and fume chemistry.

PPE Checklist for All Four Processes

• Arc-rated hood or helmet with the correct lens shade (typically 10 to 13 for these processes), plus #2 to #5 shading safety glasses worn underneath.
• Leather gloves sized to the process: heavier gauntlet gloves for stick and flux-cored, thinner TIG gloves for finger control.
• FR jacket or leathers with cuff-over-cuff sleeves. No hoodies, synthetic fabrics or rolled cuffs.
• Leather over-ankle boots — molten spatter falls downward and does not bounce kindly.
• Respiratory protection as your ventilation assessment requires.
• Fire watch, extinguisher and screens whenever welding near combustibles or in a shared space.

Certification and Qualification: AWS D1.1 and the Welder Card

Knowing the processes and being able to prove it are different things, and the paycheck gap between them is large. Structural steel welding in the United States is governed by AWS D1.1, the Structural Welding Code, which defines how welders and welding procedure specifications are qualified: a test plate or pipe in a required position, witnessed or documented by an accredited examiner, resulting in a qualification valid for a defined period of continuity. The AWS Certified Welder program documentation outlines the current performance-based routes, while the Certified Welding Inspector (CWI) credential is a separate, more advanced path. Many employers require certification before day one; many more will pay for it, because qualified welders are the bottleneck that keeps fabrication shops turning down work.

Treat safety as a skill you learn the same way you learn travel speed and arc length: deliberately, early, and before bad habits set in. Get your ventilation right, wear the gear every single time, and get qualified while your employer is willing to pay for the test. The four processes will earn you a living; the habits above are what let you collect the paycheck for forty years.

Common Mistakes, Troubleshooting and How to Learn All Four

Every welder you admire started by making a mess. What separates the welder who stays frustrated from the one who improves fast is learning to read the weld instead of guessing at it. Porosity, undercut, burn-through and spatter are not bad luck. They are messages about gas, heat, angle or preparation, and once you know the language, most defects point straight back to one of the four processes.

Mistakes Beginners Make in Each Process

MIG (GMAW): The classic errors are running the wrong gas on the wrong job, holding the wire stick-out far too long, and welding over paint, mill scale or oil. Travel speed drifts too fast, so the wire drags through the puddle instead of melting into it. Aluminum magnifies every one of these problems, which is why Aluminum MIG Welding: The Complete Practical Guide puts such heavy emphasis on cleaning and contact-tip-to-work distance.

Stick (SMAW): Wrong polarity is the quiet killer. Most general-purpose rods run on DC reverse, and running them on straight polarity gives weak, shallow welds that look almost right. Beyond that: damp rods, arcs held too long, and reaching for a 1/8 in. rod on thin metal that called for a 3/32 in. rod. The process itself remains worth learning, as covered in Advantages of Stick Welding: Why SMAW Still Wins.

TIG (GTAW): Beginners forget to add filler, dip the tungsten into the puddle and contaminate it, or skip the argon purge on stainless tube and watch the inside turn sugar-black. On aluminum, forgetting AC means losing the cleaning action that strips the oxide layer.

Flux-cored (FCAW): The most expensive mistake is running self-shielded wire while feeding gas, or the reverse. Others include ignoring interpass temperature on heavy plate, leaving slag trapped between passes, and using a stick-out far longer than the wire manufacturer specifies, which wrecks arc stability and boosts fume.

Quick Troubleshooting Guide

Defect	Likely cause	Fix
Porosity (pinholes)	Lost gas shield, long stick-out, damp or dirty metal, drafts	Clean the joint, shorten stick-out, shield the area from wind
Undercut	Amperage too high, travel too fast, wrong torch angle	Slow down, ease the heat, weave slightly along the toes
Lack of fusion	Cold joint, amps too low, poor angle, gap too tight	Increase heat, aim at the joint root, hold correct travel angle
Burn-through	Excess heat on thin stock	Drop amperage, stitch-tack, pause at edges to let it cool
Excessive spatter	Wrong polarity, voltage too high for the transfer mode, wet wire	Check settings, change the tip and liner, dry stored wire

Two environmental habits prevent a surprising share of defects. Keep your work area free of drafts, and remember that NIOSH advises welders to stay upwind in open environments because welding outdoors does not guarantee adequate ventilation. Good shielding and good breathing go together.

A Realistic Learning Path

If you are teaching yourself or hiring a beginner, the sensible order is: start with MIG, the most forgiving process and the fastest route to a decent bead; add stick, which teaches puddle control and works anywhere without gas bottles; progress to TIG, which demands the most hand-eye coordination but rewards you with the highest-quality joints; and keep flux-cored for heavy work where deposition rate and penetration matter more than appearance.

Practice on scrap coupons in flat, horizontal, vertical and overhead positions before touching anything structural. A structured Aluminium Welding Course: What You Learn, Costs & Careers shows what formal training typically covers, and registered apprenticeships remain one of the cheapest routes into paid, supervised practice.

Credentials and the Hiring Gap

Formal qualification matters once money and safety are on the line. AWS issues the Certified Welder credential through performance tests, typically to AWS D1.1-style procedures, while the Certified Welding Inspector (CWI) credential covers inspection. Employers in structural and pipeline work routinely ask for proof that you can weld to a written procedure, not just that you can lay a bead.

The opportunity is unusually large right now. AWS projects roughly 80,000 welding jobs to be filled each year between 2025 and 2029, while the Bureau of Labor Statistics projects about 40,300 welder openings annually through 2035, most driven by retirements and occupational transfer. Manufacturing employs about 63% of U.S. welders, followed by specialty trade contractors at 8%.

Bringing It All Together

That farmer’s blower band came back to life because someone matched the process to the job. Stick is your portable, weatherproof problem-solver for dirty, thick and positional work. MIG is the fast, friendly workhorse for clean steel, stainless and aluminum in the shop. TIG is the precision instrument for thin material, exotic alloys and welds that must look as good as they perform. Flux-cored is the production heavyweight for thick plate, structural steel and hardfacing outdoors. None of them is the “best” welding process. The best one is the process that matches your metal, your thickness, your location and your skill today, and the sooner you learn all four, the more jobs you can finish before lunch.

Frequently Asked Questions

What are the 4 types of welding processes?

The four main arc welding processes are shielded metal arc welding (SMAW, or stick), gas metal arc welding (GMAW, or MIG), gas tungsten arc welding (GTAW, or TIG) and flux-cored arc welding (FCAW). Together they cover the vast majority of manual welding done in fabrication shops, construction and repair work.

Which welding process is best for beginners?

MIG welding is generally the easiest to learn because the wire feed does most of the work and the gun trigger controls the arc automatically. With a little practice a first-time user can produce a sound, good-looking weld, which is why most training programs start there.

Which welding process is strongest?

Strength depends more on joint design, penetration and workmanship than on the process itself. Flux-cored and stick welding deliver deep penetration on thick steel, while TIG produces the highest-quality, most defect-free welds when done by a skilled operator.

Can one machine perform more than one process?

Yes. The same wire welder can run MIG wire or flux-cored wire, since flux-cored welding needs no shielding gas bottle in the self-shielded form. Most TIG machines also have stick welding capability, which is why they are sold as TIG/Stick welders.

Which process works best outdoors?

Stick and self-shielded flux-cored welding are the best outdoor options because their electrodes are self-shielding and far less affected by drafts. MIG and TIG rely on a shielding gas that wind can blow away, producing porosity.

What is the difference between MIG and flux-cored welding?

MIG uses a solid wire plus an external shielding gas, while flux-cored uses a hollow tubular wire filled with flux that generates its own shielding gas and a protective slag. Flux-cored deposits metal faster and tolerates dirt and wind better, but produces more fume and spatter.

Why does TIG welding cost more?

TIG equipment has the highest purchase cost of the four, uses more expensive tungsten electrodes and inert gas, and moves much slower, so labor cost per inch of weld rises. You are paying for precision, clean appearance and full control of heat input.

How dangerous is welding fume exposure?

Acute exposure can cause eye, nose and throat irritation, dizziness and nausea, while prolonged exposure may cause lung damage and increased cancer risk. NIOSH reports welders face a 40% higher relative risk of lung cancer, so ventilation, positioning and respiratory protection matter in every process.