Types of Arc Welding: The Complete Guide to 9 Processes (2026)

A maintenance crew at a mid-size fabrication shop once told me their welder could only run stick electrodes—so when a 4,000-pound stainless tank showed up for a sanitary weld, they had to sub the whole job out. The arc was the same electricity, but the process was wrong. Understanding the types of arc welding isn’t trivia; it’s the difference between winning and losing a contract.

Introduction: Why the Arc Has More Than One Personality

A maintenance crew at a mid-size fabrication shop once told me their welder could only run stick electrodes. Then a 4,000-pound stainless tank rolled through the gate needing a sanitary weld. Same shop, same electricity, same arc — but the wrong process entirely. They subbed the whole job out. That story sticks with me because it captures what most beginners, and plenty of experienced welders, get wrong about this trade: “arc welding” is not one technique. It’s a family of processes, and each member of that family has its own personality, its own strengths, and its own hard limits.

If you’ve typed “types of arc welding” into a search bar, you’re probably not here for welding trivia. You want a clear, comparable breakdown — maybe you’re a shop owner deciding which machine to buy, a career changer weighing welding against other trades, or a DIY fabricator who just burned through a stack of E6013 rods and wants to know what else is out there. This guide is built for that decision. By the end, you’ll be able to look at a job — a rusted trailer frame, an aluminum boat transom, a section of stainless pipe — and name the right process with confidence.

What Exactly Is Arc Welding?

At its core, arc welding is beautifully simple. An electric arc is struck between an electrode and the workpiece, and that arc releases intense heat — temperatures often exceeding 6,500°F (3,600°C), hot enough to melt steel like butter. The molten base metal fuses with molten filler metal (when filler is used), and when it solidifies, you have a joint that is, in many cases, stronger than the parent metal around it.

The American Welding Society’s process family definition is deliberately broad: the unifying feature is the arc, while the shielding — the blanket that keeps oxygen and nitrogen from contaminating that white-hot weld pool — can come from flux, from an externally supplied gas, or from both. That single variable, how the weld pool gets shielded, is where the family tree splits into very different branches.

Think about what has to be controlled during those few seconds of molten metal: the atmosphere, the heat input, the filler delivery, the arc shape, and the position you’re welding in. Change any one of those and you get a distinct process with its own rulebook. That’s why a crew that can only run stick rods loses a stainless tank contract, and why a shop that owns only a MIG machine struggles the moment the wind picks up outside.

The Nine Processes This Guide Covers

Here’s the taxonomy you’ll learn to navigate, from everyday workhorses to rare specialists:

• SMAW (Stick Welding) — the consumable flux-coated electrode. The baseline every welder learns first. See what electrodes are in welding for the numbering system decoded.
• GMAW (MIG Welding) — continuously fed wire under shielding gas. The production shop’s speed demon.
• GTAW (TIG Welding) — a non-consumable tungsten electrode and hand-fed filler. The jeweler’s tool of the arc world.
• FCAW (Flux-Cored Arc Welding) — tubular wire packed with flux, in self-shielded and gas-shielded flavors.
• SAW (Submerged Arc Welding) — the arc buried under a blanket of granular flux. Massive deposition, flat positions only.
• PAW (Plasma Arc Welding) — a constricted, higher-energy-density arc derived from the TIG principle.
• ESW (Electroslag Welding) — for joining very thick sections vertically in a single pass.
• ESCW (Electroslag Consumable-Wire/Cast Welding) — a heavy-industry cousin of ESW used for casting repair and forge work.
• Atomic Hydrogen Welding — the historic pre-TIG arc process, now a niche curiosity.

Along the way, you’ll meet resistance processes like spot welding, which is worth recognizing even though the arc never enters the picture — body panels on every car you’ve ridden in are held together by it.

What You’ll Be Able to Do After Reading

Every process section in this guide follows the same pattern: how it works, what it’s good at, where it fails, and the real jobs it shows up on. Then a head-to-head comparison gives you a decision framework keyed to material, thickness, position, environment, and budget. You’ll also get the safety foundation — ventilation, fume exposure, and the PPE that keeps you intact (our complete guide to welding PPE goes deeper on gear).

The arc really does have more than one personality. The welder who understands all of them isn’t just a better technician — they’re the one the shop calls when the job that pays well walks through the door. Let’s start with the physics every one of these processes shares.

How Arc Welding Works: The Physics Behind Every Process

Every arc welding process shares a foundation. An electric arc jumps from electrode to workpiece, the arc column reaches temperatures above 6,000°F, and the base metal melts into a pool that solidifies into a joint. What differs is how the arc is controlled, delivered, and shielded. These six fundamentals explain why each method behaves as it does.

The Power Source: Constant Current vs. Constant Voltage

Welders control amperage with either constant current (CC) or constant voltage (CV).

• Constant current (CC): Holds amperage steady while voltage shifts with arc length. This fits processes where the operator manually controls arc length, so stick and TIG run on CC. If you shorten the arc, the machine compensates to keep amperage at the setting.
• Constant voltage (CV): Holds voltage steady while amperage adjusts automatically. Wire-feed processes like MIG and flux-core use CV. When the wire short-circuits into the pool, current spikes; when it pulls away, current drops. The power source self-corrects, which is why setting up a MIG welder feels forgiving to beginners.

A stick machine set to 120 amps stays near 120 amps whether the arc is tight or sloppy. A CV machine keeps voltage stable and lets current react. Modern inverters often switch modes to handle both stick and wire in one unit.

Polarity: Where the Heat Actually Goes

Current direction splits heat unevenly. With DCEP (direct current electrode positive), roughly two-thirds of the heat goes to the electrode and one-third to the workpiece. With DCEN (direct current electrode negative), heat shifts deeper into the base metal. AC alternates polarity many times per second and is standard for aluminum because it also breaks down the oxide layer.

Electrode makers label polarity on the wrapper for good reason. E7018 runs best on DCEP for a stable bead; 6010 root passes also favor DCEP; some bronze and aluminum rods prefer DCEN. Wrong polarity makes striking difficult and leads to poor welds. Our guide to electrode classifications and polarity codes explains the numbering system in detail.

Arc Initiation: Scratch, Lift, and High-Frequency Start

Three common ways start the arc:

1. Scratch start: Drag the rod across the plate like striking a match. Simple but rough, and can contaminate TIG tungsten.
2. Lift arc: Touch down, then lift. The machine senses contact and ramps current. Common on portable inverters.
3. High-frequency (HF) start: A spark jumps the gap without contact. This is standard for TIG welding aluminum sheet because touching a contaminated tungsten ruins the bead.

Shielding: Keeping Oxygen Out of the Pool

Molten steel absorbs oxygen and nitrogen instantly, creating porosity and brittle welds. Each process shields differently: stick burns flux to create gas and slag; MIG and gas-shielded flux-core use bottled gas; TIG flows inert argon or helium around a non-consumable tungsten; self-shielded flux-core generates atmosphere from internal flux; submerged arc buries the arc under granular flux. The principle is the same even when delivery differs.

Weld Pool Dynamics and the Heat-Affected Zone

Arc force, surface tension, and gravity fight inside the puddle. Position changes everything: overhead beads need less amperage and tighter control, as explained in our 4F and 4G overhead welding guide. The arc heats more metal than it melts. The strip beside the fusion zone that changes microstructure without melting is the heat-affected zone (HAZ). Excess heat widens the HAZ, softens some alloys, and invites distortion, undercut, and cracking. Defects like undercut often trace back to heat control.

Duty Cycle: Why Your Machine Needs a Break

Duty cycle shows how long a welder can run before overheating, measured over a 10-minute window at stated output. A machine rated 60% at 300A can weld 6 continuous minutes out of 10 and must idle for 4. Exceeding it triggers thermal protection and shortens machine life. Light fabrication rarely hits the limit; heavy production does. This is why specifications focus on duty cycle, not just peak amperage.

With power source behavior, polarity, start method, shielding, puddle control, and duty cycle understood, you have the framework to compare every arc welding process in the sections ahead.

SMAW (Stick Welding): The Old Reliable of Arc Welding

Ask an old-school welder what “arc welding” means and nine times out of ten they picture a stick in their hand. Shielded Metal Arc Welding (SMAW) is the process that built the bridges, ships, and pipelines of the last century, and it is still the default answer whenever the job leaves the shop. It is the only major process you can run with a simple power source, a electrode holder, a handful of rods, and nothing else: no gas bottle, no wire spool, no feeder. That simplicity is exactly why arc welding process overviews still put SMAW first in the lineup.

How the Flux-Coated Electrode Works

The consumable electrode is a length of filler metal wrapped in a powdered flux coating. When the arc strikes, three things happen at once: the bare core wire melts and becomes the weld deposit, the flux burns and produces a shielding gas cloud that keeps oxygen and nitrogen out of the molten pool, and the flux forms a solid layer of slag over the finished bead. That slag is both a blessing and a chore. It protects hot metal as it solidifies, but it has to be chipped and wire-brushed before the next pass or you trap it inside the weld.

Reading the Electrode Code: What E6018 Really Means

Every stick electrode carries an AWS classification that tells you almost everything you need before you strike an arc. Take E6018: E stands for electrode, 60 means the finished weld is rated at 60,000 psi tensile strength, the 1 means the rod is qualified for welding in all four positions (flat, horizontal, vertical, and overhead), and the 8 identifies a low-hydrogen coating with iron powder added for extra deposition. Our deeper breakdown of electrode numbering and selection walks through the full system, including the middle digit that codes welding position.

Four rods cover most real work:

That E6010 root pass run on DCEP is a classic industry standard technique: the deep arc force burns through fit-up gaps and mill scale and leaves a clean, well-fused root that a 7018 cap can follow. Our guide to pipe welding procedures and passes shows how the root, hot, fill, and cap sequence fits together.

Amperage, Polarity, and Position

Most stick machines put out roughly 40 to 300 amps. As a working starting point, a 3/32-inch 7018 runs in the neighborhood of 80–110 amps, a 1/8-inch rod around 110–140 amps, and a 5/32-inch rod from about 140 up toward 200 amps on thicker plate. Settings shift with position and material: vertical and overhead run cooler to keep the puddle from sagging, while flat runs hotter for speed. For dialing in the low end, see 3/32 E7018 amperage settings and 5/32 E7018 settings and technique. Overhead, which intimidates most learners, gets its own treatment in overhead stick welding, and travel angle direction is covered in push or pull technique.

Where SMAW Still Wins

• Field and repair work. Wind, damp, rust, paint, and imperfect fit-up are routine outdoors, and stick tolerates all of them better than any gas-shielded wire process.
• Pipelines. Root passes, tie-ins, and tie-in repairs in the ditch are almost always SMAW.
• Structural steel and shipbuilding. Field erection and restricted-access joints favor a process that needs no bottle or feeder.
• Maintenance. A single machine can weld plate, pipe, and cast iron in the same afternoon. New to the process? Start with is stick welding hard.

The equipment list stays refreshingly short: a power source, leads and reliable cable connectors, a stinger, a chipping hammer, and proper welding PPE.

Limitations to Respect

SMAW is slower than MIG, and deposition rates fall well behind wire processes. Every rod leaves a stub you throw away, stop-and-start work means changing rods constantly, and slag left behind causes inclusions that show up on X-ray. Bead appearance on thin material takes practice: burn-through and distortion are common, as our guides to stick welding thin metal and stick welding sheet metal explain. Low-hydrogen 7018 rods also pick up moisture from the air if left out, so they belong in a rod oven or sealed container.

GMAW (MIG Welding): Speed, Simplicity, and Shop Efficiency

If SMAW is the old reliable, Gas Metal Arc Welding (GMAW) is the production workhorse. Commonly called MIG welding — though “MIG” technically stands for Metal Inert Gas — the process feeds a continuous spool of bare wire electrode through a handheld gun, so there’s no stopping every few inches to swap a stick electrode. That single design choice is why GMAW dominates automotive work, sheet metal shops, and any operation where inches of weld per hour matter.

As the AWS Welding Digest GMAW overview explains, the wire serves as both the electrode and the filler metal, while a shielding gas flowing from the gun nozzle protects the molten puddle from atmospheric oxygen and nitrogen. The result is a clean, slag-free bead that rarely needs grinding.

Shielding Gas Choices: Where Cost Meets Performance

Gas selection shapes nearly every MIG outcome. The three most common options:

• 100% CO₂ — cheapest, deepest penetration, but it produces more spatter and a less stable arc than argon blends.
• 75/25 Argon/CO₂ (C25) — the general-purpose standard for mild steel; a smoother arc with modest spatter and good penetration.
• Tri-mix (Ar/He/CO₂ or Ar/CO₂/O₂) — used for short-circuit welding on thinner steel or for faster travel on thicker sections.

Aluminum needs 100% argon — no exceptions — because CO₂ reacts with aluminum and wrecks the puddle. This is one of the first things covered in How to Set Up a MIG Welder: Complete Step-by-Step Guide.

Transfer Modes: The Real Secret of MIG

Most beginners think MIG is one process. It’s actually several, defined by how the metal crosses the arc gap:

Two facts drive the choice. Spray transfer in GMAW typically requires argon-rich gas mixes and higher current densities — drop below that threshold and the arc collapses into globular or short-circuit mode. Conversely, short-circuit transfer allows welding thin gauge sheet with low heat input and minimal distortion, which is why it’s the default setting on nearly every hobbyist machine running 20-gauge panels.

Pulsed MIG improves on both by alternating a peak current that sprays a single droplet with a background current that keeps the wire from melting back. One droplet per pulse means spray-transfer penetration without the heat of full spray, so you get all-position capability that plain short-circuit can’t match on thicker material.

Advantages and Limitations

Why shops love it:

• Fast deposition and continuous welding — no rod changes, no slag to chip.
• Easiest arc process to learn; most operators lay decent beads within a day.
• Clean, spatter-free welds with the right gas and settings.
• Pulsed modes handle out-of-position and a wider range of thicknesses.

Where it struggles:

• Wind sensitivity — shielding gas blows away outdoors, causing porosity. Self-shielded flux-core is the field alternative.
• Aluminum challenges — feeding soft wire through a liner invites bird-nesting, and aluminum needs a dedicated liner plus 100% argon.
• Gun handling — contact tip-to-work distance (stickout), gun angle, and travel speed all affect the bead more than on stick.
• Equipment cost — more to buy and maintain: gun, liner, drive rolls, gas regulator, and a spool of wire.

Because MIG involves pressurized gas, electrical circuits, and a hot gun, it’s worth reviewing MIG Welding Safety Precautions: The Complete Guide to Staying Safe in 2026 before your first session.

Where You’ll See GMAW

Automotive assembly and body repair, sheet metal fabrication, structural steel in controlled shop conditions, appliance manufacturing, and general production welding. It’s also the go-to process for tack welding, as covered in the MIG Tack Weld Guide, where speed between fits matters more than anything else.

The bottom line: GMAW trades the portability and wind tolerance of stick for raw productivity. In a shop with power, gas, and a clean environment, nothing lays metal faster.

GTAW (TIG Welding): Precision, Artistry, and Exotic Metals

When a job calls for a weld so clean that it requires little to no post-weld cleanup, there’s a good chance that Gas Tungsten Arc Welding (GTAW), more commonly known as TIG (Tungsten Inert Gas) welding, will be the process of choice. Unlike its wire-fed counterparts, TIG is not about speed, but about control. It is this precision that has solidified its place in high-stakes industries, from the production of aircraft to the sanitary joints found within gas line welding applications.

The Science Behind the Torch

At its core, GTAW uses a non-consumable tungsten electrode, meaning the arc is struck between the tungsten tip and the workpiece, with a separate filler rod added by hand. This grants the welder complete autonomy over the amount of filler metal introduced into the weld pool. To prevent atmospheric contamination, an inert shielding gas is fed through the torch, displacing oxygen and nitrogen. The most common shielding gas is argon, however, helium and argon-helium mixes are also utilized. According to OSHA, proper shielding is crucial for preventing weld defects, as well as limiting exposure to harmful fumes.

One of the greatest hurdles for new TIG welders is mastering heat input. This is where a foot pedal amperage control shines. By gradually increasing or decreasing amperage mid-weld, welders can taper their heat, drastically reducing the risk of undercutting or burn-through on thinner materials. For those looking to perfect their technique on thinner stock, our guide on TIG welding sheet metal is an excellent starting point.

Aluminum, Tungsten & The Oxide Battle

TIG truly showcases its capabilities when welding non-ferrous metals, specifically aluminum. Aluminum naturally forms an oxide layer that has a melting point of roughly 3,700°F, while the base aluminum sits around 1,220°F. Attempting to weld through this with Direct Current Electrode Negative (DCEN) alone will be futile. For this reason, Alternating Current (AC) TIG is used. With AC balance control, the electrode positive (EP) portion of the cycle breaks and removes this stubborn oxide, whilst the electrode negative (EN) portion provides penetration into the clean base metal.

To initiate an arc on aluminum without contaminating the tungsten, high-frequency start is utilized. This creates a non-contact arc, preserving the precision tip geometry that is vital for a stable arc. Furthermore, when deeper penetration or increased travel speeds are required, helium or argon-helium mixes are introduced. These mixes drastically increase the arc temperature, however, as noted by the Lincoln Electric Welding Safety FAQs, helium can cost significantly more than pure argon, making its use selective rather than standard.

Strengths, Weaknesses & Real-World Applications

The tradeoff for this level of control is productivity. With that being said, the results are incredibly hard to replicate with any other process. The table below breaks down the reality of TIG welding for those deciding between it and other arc welding processes:

Ultimately, GTAW is the process that welders refer to as “the one you learn last, but are the proudest of.” It will never win a race, but when the contract hinges on a perfect, x-ray quality bead on titanium or 300-series stainless, there isn’t another process that can measure up. For those willing to put in the hours, the reward is unmatched in both integrity and artistry.

FCAW (Flux-Cored Arc Welding): Where Stick Meets Wire

If stick welding and MIG welding had a child that inherited the toughness of the first and the speed of the second, it would be flux-cored arc welding. FCAW uses a continuously fed wire electrode, just like GMAW, but the wire isn’t solid. It’s a thin metal sheath rolled into a tube and packed with powdered flux compounds. That tubular design is the whole trick: it lets you carry the shielding chemistry and the slag-forming ingredients inside the wire itself, right to the arc.

Two Flavors: FCAW-S and FCAW-G

Welders usually split the process into two families, and the difference matters more than most beginners expect:

• Self-shielded FCAW (FCAW-S): The flux ingredients inside the wire generate their own protective atmosphere when they burn. No cylinder, no gas line, no regulator. This is why FCAW-S keeps working outdoors, in drafts, and on jobsites where a shielding gas cloud would get blown away before it could do its job.
• Gas-shielded FCAW (FCAW-G): The flux helps, but an external gas (typically CO₂ or an argon/CO₂ blend) does most of the shielding. In exchange you get cleaner beads, less smoke, and smoother arc characteristics that feel closer to hardwired MIG.

That self-shielded variant is the direct answer to GMAW’s biggest weakness. Take a MIG welder into a crosswind and you’ll watch porosity appear almost immediately; take FCAW-S into the same wind and the weld holds. If you’re trying to understand where gas choices fit into the broader picture, our guide to setting up a MIG welder walks through the shielding gas side in detail.

Deposition Rates: Where FCAW Pulls Ahead

FCAW deposition rates can exceed those of SMAW by a wide margin on thick sections. Stick welding burns an electrode down to a stub and stops; flux-cored wire never stops until you release the trigger. On heavy structural work, that translates into fewer stops, faster fill passes, and less time spent changing rods. Wire-driven processes also handle out-of-position welding better than most people assume, so vertical-up and overhead work are both realistic with the right wire and settings.

The tradeoff is mess and fume. FCAW leaves a slag coating that must be chipped and brushed (though nowhere near as much as stick), and the flux generates noticeably more visible fume than solid-wire GMAW.

FCAW vs. GMAW vs. SMAW

If you’re coming from a stick background, the transition is easier than you’d think. Electrode polarity, amperage ranges, and travel-angle fundamentals all carry over. A useful stepping stone is our electrode selection guide, since flux-cored wires are often classified in the same EXXT-X naming logic.

Where You’ll Actually See FCAW

FCAW lives where the metal is thick and the conditions aren’t perfect:

• Heavy structural steel: bridge members, building frames, and gusset work where deposition rate decides the schedule.
• Shipbuilding: long welds on thick plate, often in compartments with limited access for gas equipment.
• Outdoor construction and erection: anywhere the wind would defeat plain MIG.
• Heavy equipment and repair: worn or dirty base metal that flux chemistry tolerates better than a clean solid wire.
• Pressure vessel and heavy plate fabrication: fast root-to-cap builds on joints that would take far longer with stick.

Technique-wise, flux-cored wire rewards a push angle and consistent stickout more than most welders realize, and small parameter mistakes show up as slag inclusions or worm tracks. The flux core welding tips roundup covers the practical fixes, including wire stickout, trim settings, and travel speed.

Bottom line: FCAW is the process you choose when you need MIG-like productivity with stick-like tolerance for the real world. It’s smokier and grittier than GMAW, but on thick steel in the wind, nothing else keeps the production rate up.

The fragment is roughly… let me count. Let me estimate. The current fragment appears around 900-950 words. Need 560-840. I should keep same heading, same facts, all links. Let me count the words.

Let me count roughly by section.

Intro para: ~70 words.
SAW section: heading + ~120 + 35 + list ~30 + 90 = ~275.
PAW: ~150 + 60 + 45 = 255.
ESW: ~120 + 130 + callout 60 = 310.
AHW: ~110 + 50 = 160.
Table: ~60.
Closing: ~80.

Total ~1200? Hmm, maybe more than I think. Let me actually count carefully. Regardless, target 560-840. I’ll aim ~700.

Actually let me count precisely-ish.

Intro: “Six processes cover most of what a working welder sees. The remaining four are specialists. They show up when the job is unusually thick, unusually precise, unusually large, or unusually old. Knowing they exist matters because eventually you’ll run into a spec sheet that calls for one, and you’ll want to know why it was chosen over stick or MIG.” = 64 words.

SAW h3: 6 words.
P1: “Submerged arc welding gets its name from the arc itself: it burns completely beneath a blanket of granular fusible flux. There’s no visible flash, no spatter, and no glare to shield nearby workers. The arc melts the flux into a protective slag that also shields the weld pool from atmosphere, and an automatic feeder pushes wire into the joint at rates no hand-welder could match.” ~66.
P2: ~35.
P3: ~30.
List: ~28.
P4 (pipe welding / standards): ~65.
Subtotal SAW: ~230.

PAW h3: 6.
P1: ~65.
P2: ~55.
P3: ~40.
Subtotal ~166.

ESW h3: 5.
P1: ~50.
P2: ~95.
Callout: ~60.
Subtotal ~210.

AHW h3: 6.
P1: ~50.
P2: ~55.
Subtotal ~111.

Where each fits h3: 5.
Table: ~40.
Closing: ~75.

Total ≈ 64+6+230+166+210+111+5+40+75 = 907. So slightly long. Need ≤840. Cut ~70-100 words, or more to be safely in range. Let me target ~780.

Also need to keep all links:
1. pipe welding procedures URL
2. TIG welding sheet metal URL
3. thermite rail welding URL
4. MIG welding safety URL
5. OSHA external

Keep table too. I’ll trim filler.

Let me rewrite concisely while keeping all facts.

Facts to keep: SAW arc under flux blanket, no visible flash/spatter/glare, slag shields, automatic feeder, high deposition deep penetration clean beads, mechanized consistent, flat/horizontal only, shop-bound; applications list. PAW: constricted arc through nozzle orifice in copper alloy, focused stiff narrow jet, higher energy density, ~40,000°F hotter than sun’s surface, keyhole mode full penetration single pass, thin precision aerospace/instrumentation/medical/stainless; TIG sheet metal link. ESW: not arc process, resistance of molten slag, vertical, water-cooled copper shoes, consumable wire/strip, sections up to several inches thick single vertical pass, press & rolling-mill dies, generator frames, ship hull blocks, heavy plate boxes; limitation coarse grain, high heat input, needs PWHT, not thin/field. Callout analogy. AHW: predates TIG, arc between two tungsten electrodes, hydrogen stream, H2 splits into atoms recombine releasing heat, before 1940s one of few ways to weld stainless/high-melting metals cleanly, replaced by GTAW safer/better shielding, survives specialized maintenance/toolroom, historical procedures/military surplus/old manuals reference. Thermite link. Table. Closing: learn stick/MIG first, fume exposure & ventilation, MIG safety link, OSHA link.

Now write ~780 words. Let me draft and count.

Draft:

SAW, PAW, ESW, and Atomic Hydrogen: The Heavy-Hitters and Specialists

(heading words don’t count much but fine)

Six processes cover most of what a working welder sees. The remaining four are specialists — they show up when the job is unusually thick, precise, large, or old. Eventually a spec sheet will call for one, and you’ll want to know why it beat stick or MIG.

(~45)

Submerged Arc Welding (SAW): The Invisible Arc

SAW burns the arc completely beneath a blanket of granular fusible flux. No flash, no spatter, no glare to shield nearby workers. The flux melts into a slag that shields the pool, while an automatic feeder drives wire into the joint at rates no hand-welder can match.

(~48)

The result is very high deposition, deep penetration, clean bead profiles, and travel speeds that make stick welding look like a hobby. Because it’s mechanized, quality stays consistent across long, repetitive seams.

(~32)

The trade-off is geometry. SAW essentially requires flat or horizontal positions, and the flux bed needs containment, so it lives in fabrication shops. You’ll find it welding:

(~28)

• Wide plates and heavy rolled cylinders
• I-beams and structural box sections
• Pressure vessels and storage tanks
• Long seam welds on ship hull sections and pipe

(~28)

In heavy fabrication it’s the default answer to “how do we weld two inches of steel without taking all day?” Smaller work in the same shop follows documented procedures like those in pipe welding procedures, a useful preview of how WPSs work.

(~40)

Plasma Arc Welding (PAW): The Constricted Super-TIG

PAW starts with the GTAW idea, then squeezes the arc through a small nozzle orifice in a copper alloy. That constriction does two things: it focuses the arc into a stiff, narrow jet and raises its energy density. The plasma jet reaches roughly 40,000°F — hotter than the surface of the sun and far more concentrated than an open TIG arc.

(~62)

At higher settings PAW runs in keyhole mode: the jet punches a hole through the joint, the molten pool flows behind it, and the hole closes into a full-penetration weld in one pass. That’s how PAW beats TIG on thicker material while holding a narrow, precise bead.

(~50)

It fits thin-section precision work — aerospace ducting, instrumentation, medical devices, stainless assemblies where TIG is close but not quite hot or fast enough. Practitioners often start with TIG welding sheet metal before stepping up to a plasma unit.

(~40)

Electroslag Welding (ESW): Miles of Vertical Steel

ESW isn’t really an arc process. Once started, heat comes from the electrical resistance of molten slag rather than an arc. The weld runs vertically, water-cooled copper shoes guiding a pool of slag and metal up the joint while a consumable wire or strip melts in.

(~48)

The payoff is enormous: sections up to several inches thick join in a single vertical pass. That makes ESW the go-to for press and rolling-mill dies, generator frames, ship hull blocks, and heavy plate boxes that would otherwise take weeks of multiple passes. The limitation is grain structure and heat input — the coarse-grained zone usually demands post-weld heat treatment, and ESW doesn’t suit thin material or field positions.

(~72)

Callout same (~60).

Atomic Hydrogen Welding (AHW): The Historical Curiosity

AHW predates TIG. An arc is struck between two tungsten electrodes while hydrogen flows through it; the arc splits H₂ into atoms that recombine on the workpiece and release intense heat. Before the 1940s it was one of the few ways to weld stainless and other high-melting-point metals cleanly.

(~50)

Today GTAW does everything AHW did, safer and with better shielding, so atomic hydrogen survives in specialized maintenance and a few toolroom niches. It’s still worth recognizing, since historical procedures, military surplus equipment, and old shop manuals reference it. For another niche method that still runs the world’s railroads, see thermite rail welding.

(~58)

Where Each Process Fits

Table (~40).

None of these will be your first process. Learn stick or MIG first, and understand fume exposure and ventilation early — the same MIG welding safety practices apply broadly. These specialists become recognizable the moment a drawing or spec calls for them. For context on why fume controls matter across every process above, OSHA’s welding, cutting, and brazing hazard guidance is the authoritative starting point.

(~65)

Rough total: intro 45 + SAW (6+48+32+28+28+40=182) + PAW (6+62+50+40=158) + ESW (5+48+72+60=185) + AHW (6+50+58=114) + table heading 5 + table 40 + closing 65 = 794. Good, within range. Maybe trim a bit to be safe — 794 is fine, under 840.

Actually let me be careful with counting; my counts are approximate. I’d rather target ~760-800. Let’s slightly trim the closing or intro. It’s fine.

Let me write final HTML. Ensure links preserved with exact URLs.

Also the heading must be h2 with strong. Good.

SAW, PAW, ESW, and Atomic Hydrogen: The Heavy-Hitters and Specialists

Six processes cover most of what a working welder sees. The remaining four are specialists — they show up when the job is unusually thick, precise, large, or old. Eventually a spec sheet will call for one, and you’ll want to know why it beat stick or MIG.

Submerged Arc Welding (SAW): The Invisible Arc

SAW burns the arc completely beneath a blanket of granular fusible flux. No flash, no spatter, no glare to shield nearby workers. The flux melts into a slag that shields the pool from the atmosphere, while an automatic feeder drives wire into the joint at rates no hand-welder could match.

The result is very high deposition, deep penetration, clean bead profiles, and travel speeds that make stick welding look like a hobby. Because the process is mechanized, quality stays consistent across long, repetitive seams.

The trade-off is geometry. SAW essentially requires flat or horizontal positions, and the flux bed needs containment, so it lives in fabrication shops. You’ll find it welding:

• Wide plates and heavy rolled cylinders
• I-beams and structural box sections
• Pressure vessels and storage tanks
• Long seam welds on ship hull sections and pipe

In heavy fabrication it’s the default answer to “how do we weld two inches of steel without taking all day?” Smaller work in the same shop follows documented procedures like those outlined in pipe welding procedures, a useful preview of how a real WPS works.

Plasma Arc Welding (PAW): The Constricted Super-TIG

PAW starts with the GTAW idea, then squeezes the arc through a small nozzle orifice in a copper alloy. That constriction does two things: it focuses the arc into a stiff, narrow jet and raises its energy density. The plasma jet reaches roughly 40,000°F — hotter than the surface of the sun and far more concentrated than an unconstrained TIG arc.

At higher settings PAW runs in keyhole mode: the jet punches a hole through the joint, the molten pool flows behind it, and the hole closes into a full-penetration weld in a single pass. That’s how PAW beats TIG on thicker material while holding a narrow, precise bead.

It suits thin-section precision work — aerospace ducting, instrumentation, medical devices, and stainless assemblies where TIG is close but not quite hot or fast enough. Practitioners comparing setups often start with TIG welding sheet metal before stepping up to a plasma unit.

Electroslag Welding (ESW): Miles of Vertical Steel

ESW isn’t really an arc process. Once started, heat comes from the electrical resistance of molten slag rather than an arc. The weld runs vertically, water-cooled copper shoes guiding a pool of slag and metal up the joint while a consumable wire or strip melts in.

The payoff is enormous: sections up to several inches thick can be joined in a single vertical pass. That makes ESW the go-to for press and rolling-mill dies, generator frames, ship hull blocks, and heavy plate boxes that would otherwise take weeks of multi-pass welding. The limitation is grain structure and heat input — the coarse-grained zone usually demands post-weld heat treatment, and ESW doesn’t suit thin material or field positions.

Atomic Hydrogen Welding (AHW): The Historical Curiosity

AHW predates TIG. An arc is struck between two tungsten electrodes while hydrogen gas flows through it; the arc splits H₂ into atoms that recombine on the workpiece, releasing intense heat. Before the 1940s it was one of the few ways to weld stainless and other high-melting-point metals cleanly.

Today GTAW does everything AHW did, safer and with better shielding, so atomic hydrogen survives in specialized maintenance and a few toolroom niches. It’s still worth recognizing, since historical procedures, military surplus equipment, and old shop manuals reference it. For another niche method that still runs the world’s railroads, see thermite rail welding.

Where Each Process Fits

None of these will be your first process. Learn stick or MIG first, and understand fume exposure and ventilation early — the same MIG welding safety practices apply broadly. These specialists become recognizable the moment a drawing or spec calls for them. For context on why fume controls matter across every process above, OSHA’s welding, cutting, and brazing hazard guidance is the authoritative starting point.

Head-to-Head Comparison: Choosing the Right Arc Welding Process

You now know how each process works in isolation. But nobody walks into a shop and asks for “arc welding” in the abstract. They walk in with a job: a 16-gauge aluminum panel, a 2-inch stainless line that has to pass a sanitary inspection, a field of structural joints in a crosswind. The right process falls out of six questions — what metal, how thick, what position, how fast, what budget, and where the work happens.

The Six-Question Decision Framework

Material type. Carbon steel is the easy case: all six processes weld it. Stainless splits the field — SMAW works but wastes corrosion resistance in the dilution, while GTAW on stainless sheet keeps the bead clean and inspectable. Aluminum is the gatekeeper: it needs the cleaning action of AC in GTAW or a properly tuned pulsed GMAW setup. Copper and exotic alloys effectively force you to TIG.

Thickness. Thin material (under about 3 mm) punishes heat input, which favors short-circuit GMAW or GTAW with a foot pedal. Thick plate is where the heavy processes earn their keep — FCAW’s higher deposition eats through 10 mm-plus passes faster than stick, and SAW and electroslag handle the very heavy sections that would take a stick welder all shift.

Position. SMAW and GTAW are truly all-position. GMAW covers all positions with pulsed transfer and a steady hand; FCAW-G does well out-of-position, FCAW-S less so. SAW is the strictest — flat and horizontal only, no exceptions. If the joint is overhead, start with stick or pulsed MIG techniques rather than fighting gravity with a process that was never designed for it.

Environment. Indoors, gas-shielded processes rule. Outdoors in wind, shielding gas blows away and porosity follows — that single fact makes SMAW the most forgiving field process, with self-shielded FCAW as its wire-fed cousin. GMAW’s speed advantage disappears the moment you need tarps, wind screens, and a bottle you have to haul up a scaffold.

Three Real Scenarios

“I need to weld aluminum sheet.” Thin aluminum drains heat and hides porosity. Choose GTAW with AC balance control and high-frequency start, or pulsed GMAW with 100% argon if volume matters more than finesse. Dialing in a MIG machine with the wrong gas or a dirty brush is how most aluminum jobs fail before the arc strikes.

“I need structural outdoor welds in wind.” SMAW is the default answer and stick is more learnable than its reputation suggests. If you want wire-feed speed outdoors, specify self-shielded FCAW and budget for heavier fume extraction. Flux-core technique rewards a shorter stickout and a slower, deliberate travel speed than solid-wire MIG habits will give you.

“I need sanitary stainless pipe.” Root pass with GTAW (often 100% argon purge), hot pass and cap per the procedure. This is code work, so the joint design, positions, passes, and inspection all live in the WPS — our pipe welding procedures guide walks through that paperwork. A MIG/TIG combo unit is a practical buy for shops that run both clean stainless and production steel.

One last truth: the “best” process is the one whose constraints you can actually live with. GMAW is generally the fastest and cheapest for thin-to-medium steel in a shop. SMAW is the most forgiving outdoors. GTAW is the slowest travel speed but gives you the highest-quality, most inspectable weld. SAW wins on long, straight, high-volume welds and cannot weld out-of-position at all. Match the constraint first, and the process usually picks itself.

Safety, Ventilation, and Health Risks of Arc Welding

All nine processes in this guide share one hazard profile: an arc blasting out ultraviolet light, a plume of vaporized metal, and enough electrical energy to stop your heart. What changes between processes is how much fume you produce and how you control it. FCAW throws more smoke than GMAW, stick welding buries its fume under a flux bed, and GTAW is comparatively clean but still generates UV and ozone. The safety fundamentals barely move.

What’s Actually in Welding Fume

Welding fume isn’t one thing. It’s a shifting cocktail of ultrafine particles and gases formed when the electrode, coating, shielding gas and base metal are vaporized by arc temperatures that can exceed 6,000°F. The usual culprits:

• Manganese — present in virtually all steels and consumables; long-term overexposure is linked to nervous system effects, sometimes called “manganism,” with tremor and coordination problems resembling Parkinson’s disease.
• Hexavalent chromium — released when welding stainless steel or chrome-bearing alloys; a known carcinogen, and the reason stainless work demands serious ventilation.
• Zinc and nickel — zinc fume is the classic cause of metal fume fever, while nickel compounds are associated with lung cancer risk.
• Iron oxide — the reddish-brown smoke of mild steel welding, less toxic than the others but irritating in quantity.
• Fluorides and silicates — released from flux coatings, especially in stick and flux-cored processes.

OSHA’s welding fact sheet identifies metal fume fever, lung damage and nervous system effects as the primary outcomes of fume exposure. Metal fume fever arrives hours after exposure with chills, fever, nausea and a metallic taste, then fades in a day. It feels like a bad flu, and welders shrug it off — which is exactly the problem. Repeated episodes are a warning sign, not bad luck.

Ventilation: What OSHA 1926.353 Actually Requires

The governing U.S. construction standard is 29 CFR 1926.353, which requires general mechanical ventilation sufficient to keep fume exposure below permissible limits. In practice that means at least 20 cubic feet per minute of fresh air per square foot of floor area when natural ventilation isn’t enough, with exhaust hoods or ducted local exhaust positioned to draw fume away from the welder’s breathing zone. General industry falls under the related guidance on OSHA’s hazards and solutions page.

When ventilation can’t bring concentrations into compliance, respiratory protection becomes mandatory — supplied air, or at minimum a fitted, seal-checked half-mask with P100 cartridges. Self-shielded FCAW and field stick welding are the usual trouble spots, since both pump out heavy fume outdoors or in partially enclosed spaces. Flux-cored work deserves particular attention; our flux core wire welding tips explain how wire selection drives smoke output.

Confined spaces add a second, quieter killer: shielding gas. Argon and CO₂ pool in low areas because they’re heavier than air, displacing oxygen before anyone notices symptoms and causing silent asphyxiation. Never weld in a confined space without continuous oxygen monitoring, forced ventilation and an attendant outside. The same logic applies to gas line welding and purging work, where inert purge gases accumulate inside pipes.

Arc Radiation, Shock, and Fire

The arc emits UV intense enough to cause photokeratitis — flash burn — within minutes of unprotected exposure. Symptoms surface hours later as gritty, tearing eyes and the sensation of sand behind your lids. It’s a sunburn on your corneas, and repeated episodes raise cataract risk. A correct helmet shade is non-negotiable, and so is shielding bystanders from the arc. The electrical side matters too: damaged leads, wet conditions and ungrounded machines raise shock risk, while poor terminations overheat. If you’re buying or maintaining gear, quality cable connectors and intact insulation are part of the safety system, not an afterthought.

Fire is the third pillar. Slag and spatter travel farther than you expect, and hot slag landing on dry material can smolder unseen for hours. Clear a 35-foot radius, cover openings, keep a charged extinguisher within arm’s reach, and post a fire watch after hot work in occupied buildings.

The PPE Short List

Our full kit rundown lives in Welding PPE: The Complete Guide to Protective Gear Every Welder Needs, but the core items are simple:

1. Auto-darkening helmet — shade 10–13, with a proper reaction time and a light state of shade 3 or 4.
2. Respiratory protection — P100 half-mask for routine work, supplied air when ventilation can’t keep up.
3. Welding gloves — thinner MIG gloves for dexterity, heavier stick gloves with longer cuffs.
4. Leathers — flame-resistant jacket and pants, no cuffs or open pockets to catch spatter.
5. Boots, ear and eye protection — steel-toe leather boots, earplugs, and safety glasses under the helmet at all times.

Gear choices shift by process, as our What Does a Welder Wear? guide covers, while MIG Welding Safety Precautions walks through wire-feed risks including the wire shard that can fire from the nozzle on a bad start. Even localized processes bite: spot welding throws molten expulsion, so we keep a dedicated weld burn first aid guide on hand.

Getting Started, Common Mistakes, and the Future of Arc Welding

Every welder you admire started with a stack of dirty plate, a hood that didn’t fit right, and a first bead that looked like a caterpillar frozen mid-stride. The difference between people who stick with it and people who quit in month two usually isn’t talent. It’s that the second group made the same six mistakes early, figured out why they happened, and fixed them. This closing section is the shortcut: the errors that stall beginners, the training routes that actually lead to a paycheck, and where the industry is dragging the arc next.

The Six Beginner Mistakes That Ruin Good Metal

• Wrong shielding gas. Running 100% CO2 on thin sheet because it’s cheap, or argon-rich mix on heavy steel where it puddles too softly, is the single most common MIG setup error. Gas choice controls arc shape, spatter, and penetration, not just cost. Get the full breakdown in How to Set Up a MIG Welder: Complete Step-by-Step Guide.
• Wrong polarity. Most solid MIG wire runs DCEP, most flux-cored wire runs DCEN, and stick electrodes vary by classification. A 7018 on the wrong polarity gives you porosity and undercut no matter how steady your hand is. The rod coding system explains itself once you learn it at What Are Electrodes in Welding? Types, Numbers, Polarity & How to Choose.
• Ignoring stickout. Contact-tip-to-work distance changes amperage more than most beginners realize. Too long and the arc goes soft and wandering; too short and you burn the tip. It’s a variable, not an accident.
• Poor joint prep. Mill scale, oil, a gap that’s either nonexistent or a canyon. No amount of amps fixes a badly fit joint.
• Running too hot or too cold. Cold lap and lack of fusion come from being timid; burn-through and undercut come from being greedy. Thin metal punishes both extremes fast, as covered in Stick Welding Thin Metal: Amp Settings, Techniques & Burn-Through Fixes.
• Skipping plate practice before pipe. Pipe is just plate that’s curved and unforgiving. Learners who jump straight to 6G positions build bad habits that a test coupon exposes immediately.

Training Paths and Certification That Employers Recognize

There are three realistic routes in. Trade school or a union apprenticeship gives you structured shop hours and instructor feedback. Community college welding programs are often cheaper, frequently evening-friendly, and increasingly offer AWS-aligned curriculum. On-the-job training works too, but you’ll advance faster if you can already read a joint and set a machine.

Certification is where the money moves. The American Welding Society offers performance-based Certified Welder testing, where you weld a test coupon that gets visually and destructively or radiographically examined against a code, with no formal coursework required. The two codes you’ll meet most are AWS D1.1 for structural steel and ASME Section IX for pressure work. Employers in construction, structural fabrication, and pressure piping generally want to see one of those stamps before they hand you a ticket. If pipe is your goal, understand the qualification ranges and positions first via Pipe Welding Procedures: The Complete Guide to WPS, Positions, Passes & Inspection.

Career Outlook: The Numbers Behind the Arc

The U.S. Bureau of Labor Statistics projects about 2 percent growth for welders, cutters, solderers, and brazers from 2025 to 2035, a pace roughly in line with all occupations. That modest headline number hides the real dynamic: most openings come from workers retiring and leaving the trade, not from brand-new demand. Meanwhile, AWS workforce data projects roughly 80,000 average annual welding job openings to be filled between 2023 and 2027. Slow growth plus heavy replacement need means welders who hold current, verifiable certifications stay in demand even when headlines look flat.

Where Arc Welding Is Heading

Four shifts are already reshaping shop floors. Pulsed MIG and globular-on-transfer modes are widening the usable window on thin and out-of-position work, giving production welders spray-transfer-like deposition without the heat input. Collaborative robot cells now sit alongside human welders, handling repetitive fillets while operators load, program, and inspect. Inverter power sources have shrunk machines, tightened arc control, and made processes like lift-arc TIG practical in field conditions. And advanced high-strength steels used in automotive and transport are forcing new thinking about heat input and filler matching, as AHSS Insights notes on arc welding processes.

None of that replaces fundamentals. Learn to read the puddle, respect your settings, and keep your gear and training current, and the specific machine in front of you becomes a detail rather than a barrier. The arc has nine personalities, but the welder who understands them all gets hired for all nine.

Frequently Asked Questions

What is the most common type of arc welding?

GMAW (MIG) is the most widely used process in production fabrication shops due to its speed and ease of learning, while SMAW (stick) remains the most common in field, repair, and pipeline work because of its portability and tolerance to outdoor conditions.

What’s the difference between MIG and TIG welding?

MIG (GMAW) uses a continuously fed consumable wire electrode and is fast and beginner-friendly. TIG (GTAW) uses a non-consumable tungsten electrode with separately fed filler rod, producing cleaner, more precise welds but at a much slower pace and with a steeper learning curve.

Can arc welding be done outdoors?

Yes—but only certain processes. SMAW and self-shielded FCAW tolerate wind well because their shielding comes from flux. Gas-shielded processes like GMAW and GTAW are easily disrupted by wind and need wind screens or sheltered conditions to avoid porosity.

Which arc welding process is best for beginners?

Most instructors start beginners on GMAW (MIG) because the wire feed is forgiving and you see results quickly. Many then learn SMAW because it’s inexpensive, portable, and builds fundamentals about arc length, polarity, and electrode angles that transfer to every other process.

What is the strongest arc welding process?

Strength depends more on joint design, material, and procedure qualification than on the process itself. GTAW generally produces the cleanest, most defect-free welds, which is why aerospace and pressure-vessel work frequently specifies it—but properly executed SMAW or FCAW welds can meet the same strength requirements.

What does E7018 mean on a stick electrode?

E stands for electrode, 70 means the weld metal has a minimum tensile strength of 70,000 psi, the first 1 indicates it can be used in all positions, and 8 indicates a low-hydrogen iron-powder coating. E7018 is the go-to structural steel electrode.

Is arc welding dangerous?

It carries serious risks—UV radiation causing arc flash, electrical shock, burns, fire, and inhalation of toxic metal fumes including manganese and chromium. These risks are well-managed with proper PPE, ventilation per OSHA 1926.353, and safe work practices.

What shielding gas does MIG welding use?

For carbon steel, a common mix is 75% argon / 25% CO2 for general work, or 100% CO2 for deeper penetration at lower cost. Stainless often uses argon/CO2/O2 tri-mixes, and aluminum requires 100% argon.