A shop foreman once told me about a $14,000 repair that failed in three days because a contractor picked MIG for a dirty, out-of-position structural joint instead of a 7018 stick electrode. Nothing was wrong with the welder’s hands — the wrong process was chosen for the job. That single mismatch is exactly why understanding the common welding types matters, whether you’re a DIYer buying your first machine or a project manager signing off on a WPS.
A shop foreman once told me about a $14,000 structural repair that failed in three days. Nothing was wrong with the welder’s hands — the man could lay a beautiful bead. The problem was that the contractor chose MIG for a dirty, out-of-position joint that called for a 7018 stick electrode. The gas shield couldn’t hold against the draft, the contaminated puddle trapped porosity, and the joint cracked under load before the paint was dry. The rework cost more than the original job.
That story is the whole argument for understanding common welding types. Process selection quietly drives cost, quality, and safety long before arc strike. The wrong process produces defects that no amount of technique can fix, inflates rework budgets, and — worst of all — creates hazards the crew never planned for.
The query means different things to different readers, and it’s worth naming them. Beginners and DIYers want to know which machine to buy first. Welding students need a map of the processes they’ll be tested on. Hiring managers and project engineers need to know which process belongs on a specification or a welding procedure specification. Maintenance crews need the process that survives a windy Tuesday in a field.
Here’s the reality behind the search: the U.S. Environmental Protection Agency’s AP-42 Chapter 12.19 states that more than 80 different types of welding operations are in commercial use, covering arc, oxyfuel, brazing, soldering, and thermal cutting. Yet a small handful handles the vast majority of real-world work. Learning those well is the highest-return investment you can make.
Classification systems cut the list into understandable groups:
The consumption numbers tell you where the work actually is. Per EPA AP-42 electrode data, SMAW accounted for 45% of electrodes consumed, GMAW 34%, FCAW 17%, and SAW 4%. Stick and MIG together dominate the trade — which is exactly why we’ll spend the most time on them, starting with electrode basics in what electrodes are and how to choose them.
Quick Note: The big names you’ll encounter throughout this guide are stick (SMAW), MIG (GMAW), TIG (GTAW), flux-cored (FCAW), submerged arc (SAW), oxy-fuel, plasma, laser, and friction stir. Spot/resistance welding, electron beam, brazing and soldering round out the rest of the map.
We’ll start with the science every arc process shares, then move through the big five one at a time — equipment, electrode or wire choices, transfer modes, best-fit jobs, and honest drawbacks. From there we widen to cutting and advanced processes, give you a head-to-head decision framework, break down the fume and health profile of each process (why proper welding PPE differs by process), and close with common mistakes, industry trends, and a numbered action plan. Whether you’re setting up a first machine with our MIG welder setup guide or signing off on production work, the goal is the same: pick the process the job actually deserves.
Before you can choose between SMAW, MIG, TIG and flux-core, it helps to strip the acronyms off. Every arc process is a different answer to the same stubborn question: how do we keep oxygen out of a molten puddle that is desperate to drink it? Steel at welding temperature pulls nitrogen and oxygen out of open air almost instantly, and the result is porosity, brittleness and a weld that looks fine right up until it fails. Flux coatings, gas bottles and purge dams all exist to solve that one problem. Once you see it that way, the family tree of welding processes stops feeling like trivia and starts feeling like common sense.
An arc welder is a loop. The power source drives current down the cable and connectors to the electrode, the electrode strikes an arc against the workpiece, and that arc — a column of ionized gas burning in the thousands of degrees — melts the base metal plus a filler material. Shielding protects the puddle while it’s liquid, the pool solidifies, and you have a fused joint rather than two pieces of metal sitting on top of each other.
The power supply itself behaves in one of two ways, as explained in the NRC’s Welding Technology and Codes training module (NRC):
| Strategy | How it works | Where you see it |
|---|---|---|
| Slag and flux | A flux coating or cored wire melts into a floating slag blanket that covers the puddle and releases shielding gas underneath | SMAW, FCAW, SAW |
| External gas | Argon, CO₂ or a mix flows from the torch nozzle across the arc | GMAW, GTAW, dual-shield FCAW |
| Vacuum or inert environment | Oxygen is simply removed — a vacuum chamber or a fully purged pipe section | Electron beam welding, purged stainless and gas-line work |
Polarity decides where heat concentrates. With DCEP (direct current electrode positive), current flows from the electrode into the plate; most stick rods run this way, and it gives a stable, well-cleaned arc. With DCEN (electrode negative), heat drives deeper into the workpiece, which is why GTAW on DCEN produces the deep, narrow penetration root passes are known for. AC alternates direction many times a second, and on GTAW it delivers an oxide-cleaning action once every half cycle — that’s precisely why AC is the default for aluminum, while DC electrode negative gives deeper penetration on steel. Tungsten selection is standardized under AWS A5.12, with A5.18 covering carbon steel filler metals for gas-shielded arc welding, and ASME uses that same filler-metal labeling system when a procedure calls out GTAW consumables (AWS).
Note: Decoding an Electrode Number. Take E7018: the E means electrode (an R would mean a bare rod), 70 is a minimum tensile strength of 70,000 psi, 1 means the rod will run in all four positions, and 8 describes the flux — low-hydrogen, iron-powder type, which also tells you which currents it accepts. Now decode ER70S-6 MIG wire: ER means electrode or rod, 70 again means 70,000 psi, S means solid (not cored), and 6 is the deoxidizer package that lets it run on dirty or lightly rusted mill scale. Same logic, one system.
If you want the full breakdown of those digits and how they map to real-world rod choice, see our guide to what electrodes in welding actually are. Current settings matter just as much as the code: a 3/32 E7018 runs very differently from a 5/32, as covered in 3/32 E7018 amperage, polarity and how to run it.
Wire processes add another variable — the way metal crosses from the wire to the puddle. Short-circuit transfer shorts the wire to the work dozens of times per second, giving low heat and excellent control on thin sheet. Globular transfer drops big irregular globules; it’s cheap on gas but messy. Spray transfer fires a fine stream of droplets at higher voltage for fast, deep, high-deposition welds in the flat position. Pulsed spray alternates a high-current spray pulse with a background current, so you get spray-transfer penetration without the heat — a favorite for out-of-position and thin-material work. Getting these settings right is half the battle in setting up a MIG welder, and the same thinking applies to dialing in TIG settings on sheet metal.
Quick Note: Safety standards sit underneath all of this. OSHA’s 29 CFR 1910.252 for welding, cutting and brazing references ANSI Z49.1, Safety in Welding, Cutting, and Allied Processes, published by the American Welding Society, as the governing practice document. Learn the process, then read the standard — the two go together.
Understanding polarity, transfer mode and shielding is also what makes procedure work click. When a WPS for a critical joint specifies filler classification, position and current type, it’s describing exactly the variables covered above, which is why pipe welding procedures and inspection leave no room for guessing. With the science down, we can finally look at each process on its own terms.
Out of the handful of processes that cover the vast majority of real-world jobs, one has earned its spot at the top for decades: Shielded Metal Arc Welding, better known as SMAW or “stick welding”. According to NRC training material, SMAW is the “most widely used process in the world”, with proven use in several nuclear applications, especially for repairs. The reason is simple: few other processes offer this much reliability with so little setup.
At its core, SMAW uses a consumable metal electrode coated in a carefully formulated flux. When you strike an arc, the flux burns and produces a shielding gas that keeps oxygen and nitrogen out of the molten puddle. At the same time, it forms a layer of slag over the solidifying weld. This slag protects the hot metal from contamination as it cools, and is chipped off after each pass.
This built-in shielding is what sets stick apart from gas-shielded processes like MIG or TIG. You don’t need a gas cylinder to shield the puddle, which is exactly why stick thrives where wind, rain, or remote access would blow external gas away. If you’re still learning the basics, our guide on What Are Electrodes in Welding? breaks down how flux types affect arc behavior even further.
Stick welding gear is about as minimal as it gets: a power source, leads, an electrode holder, a ground clamp, and a box of rods. With the right welding connectors, this compact setup can be hauled to job sites with no need for a wire feeder or shielding gas cart. On top of that, many electrodes allow welding in every position: flat, horizontal, vertical, and overhead. For this reason, SMAW remains the default for field work, pipelines, maintenance, and repair.
This dominance shows up in the numbers. EPA emission data attributes roughly 45% of total electrode consumption to SMAW — the largest share of any process. With that much use comes exposure, too. OSHA lists SMAW highest among arc processes in order of decreasing fume production since the flux coating burns during welding. A CDC/NIOSH study measured a mean total welding fume of 630 µg/m³ for SMAW workers, versus 510 µg/m³ for GMAW and 46–77 µg/m³ for GTAW. Pairing this with proper welding PPE is non-negotiable to avoid issues like weld burns.
Quick Note: When you need to weld outdoors in wind, on rusty or dirty steel, out of position, or with minimal gear, stick beats nearly every other common process.
Picking the right rod makes or breaks a stick weld. The most common families you’ll see on the job are E6010, E6011, E6013, and E7018. For a full breakdown of these codes, see 3/32 E7018 Amperage and 5/32 E7018 Amperage.
| Electrode | Strength (ksi) | Polarity | Best Use |
|---|---|---|---|
| E6010 | 60 | DCEP | Deep penetration, root passes, dirty/rusty steel |
| E6011 | 60 | AC/DC+ | Similar to 6010 but runs on AC machines |
| E6013 | 60 | AC/DC± | Smooth beads, sheet metal, easier for beginners |
| E7018 | 70 | DCEP | Low-hydrogen, strong, clean, ideal fill/cap |
The “E” means electrode. The first two digits show tensile strength. The third digit shows position. The fourth relates to coating type and polarity. This matches common practice seen in AWS Standard Welding Procedure Specifications, which often pair E6010 or E6013 root passes with E7018 fill and cap for carbon steel from 1/8 in. to 1-1/2 in. thickness.
SMAW also covers cast iron with nickel-based rods, and select stainless electrodes for stainless repairs. However, thin-gauge work is tricky. Check Stick Welding Sheet Metal or Stick Welding Thin Metal before tackling light stock.
For all its grit, stick isn’t flawless. Expect more spatter than wire processes, slag inclusions if not removed between passes, restart porosity from poor technique, and a slower deposition rate overall. Learning proper angles matters too — our Travel Angle Welding and Push or Pull Stick Welding guides cover this in depth. For out-of-position work, Overhead Stick Welding is worth reviewing. Wondering about difficulty? Is Stick Welding Hard? gives an honest take.
On-farm fix: A maintenance welder needs to repair a cracked farm implement outdoors in wind with only a small engine-driven welder on hand. Gas-shielded options would be unstable. With E6011 on AC, or E7018 if prepped and dry, SMAW lets them strike, burn through light rust, and tie in the crack solidly without hauling extra gear. It’s this exact type of field repair that keeps stick in every toolbox.
Quick Note: Choose stick when portability, all-position, and outdoor toughness outweigh speed and cosmetic perfection. Avoid it for high-volume sheet runs where flux-core, MIG, or combo units will outpace you.
If stick welding is the field soldier of the welding world, GMAW is the factory floor manager. Ask almost any professional what “MIG” means and you’ll hear “easy to learn, hard to master” — and that reputation is earned. The AWS Welding Digest defines GMAW as an electric arc welding process that uses a continuously fed wire electrode and an external shielding gas, and it notes the process is favored for its speed and versatility across automotive, aerospace, energy, and general manufacturing.
Here’s the whole idea in one sentence: a spool of wire feeds continuously through the torch, an arc melts that wire into the joint, and a bottle of gas shields the puddle from oxygen. Because the wire is always feeding, you never stop to change rods the way a stick welder does. You hold the trigger, the wire advances, the arc runs, and you keep welding until the wire runs out.
That continuous feed changes everything about workflow. No arc-out restarts, no rod stubs to throw away, higher deposition per hour, and a much shallower learning curve. For anyone setting up their first machine, our How to Set Up a MIG Welder guide walks through gas, wire, polarity, and settings from scratch.
GMAW is not one process — it’s a family. OSHA identifies four major types of GMAW, categorized by shielding gas and metal transfer mode. Understanding them is the difference between a clean bead and a spattery mess:
Quick Note: OSHA also points out that GMAW can be welded in all positions with no slag to trap in the weld — which is why it’s so forgiving for beginners compared to stick or flux-core.
Your gas and wire pairing sets your ceiling. Common shielding gas options include:
On the wire side, ER70S-6 is the default for mild steel — the “6” means extra deoxidizers, which is why it tolerates slightly rusty or oily metal. ER309 wire handles dissimilar joints; AWS SWPS documents use ER309 for carbon-to-stainless connections. “Hard wire” is plain solid MIG wire, while silicon-deoxidized wire like the -6 contains added silicon and manganese for cleaner puddles on less-than-perfect base metal. Our guide to electrode and filler classification codes breaks down how to read these designations.
Terminology causes real confusion. In Europe, “MIG” technically means Metal Inert Gas (argon/helium), while “MAG” means Metal Active Gas (CO₂ or argon/CO₂ blends). Since almost everyone runs active gas on steel, the terms blur together — in the U.S., “MIG” covers all of it.
The bigger misconception is “gasless MIG.” There is no gasless MIG. Machines that weld without a bottle are running flux-cored wire (FCAW-GS), which shields itself with a flux core. It works outdoors in wind, but it’s a genuinely different process with different settings and slag — our flux-core wire techniques guide covers the details.
Picture a hobbyist welding a go-kart frame in a two-car garage: C25 gas, ER70S-6 at .030″, short-circuit transfer, a 180-amp multiprocess machine. Total setup cost under a thousand dollars, and he’s laying usable beads within a weekend. Now picture the production line fabricating the same frame: pulsed-spray transfer, robotic arm, tri-gas blend, dedicated fixtures, and a written WPS. Same process family, ten times the throughput, and a fume extraction hood over the cell — because NIOSH-measured particle diameters of about 149 nm place GMAW fume in the ultrafine fraction, which research links to greater inflammatory pulmonary effects.
That fume and spatter profile is GMAW’s honest trade-off: easier and faster to learn than TIG on sheet or stick in structural work, but dirtier air for the operator. Adequate ventilation and proper PPE aren’t optional — see our complete welding PPE guide before your first arc.
If stick welding is the rugged field general and MIG is the production workhorse, TIG is the surgeon. Gas Tungsten Arc Welding (GTAW) strikes an arc from a non-consumable tungsten electrode while a separate bottle feeds inert shielding gas to the puddle. You add filler rod by hand, or you don’t add any at all. There’s no flux to chip, no slag to trap, and no wire feeder making decisions for you.
That independence is the whole point. The NRC’s training material on GTAW describes it as a process using a non-consumable tungsten electrode that can run with or without filler material, and its controlled heat input makes it a natural fit for orbital welding and corrosion-resistant overlays in nuclear service. OSHA’s welding fact sheet goes further, crediting GTAW with a “superior finish” thanks to its non-consumable electrode and externally supplied inert gas shield.
The inert gas — almost always argon, sometimes helium or a mix — pushes atmospheric oxygen and nitrogen away from the molten puddle. No oxygen means no oxides, no porosity from atmospheric contamination, and no flux inclusions. The result is a weld that passes X-ray and dye-penetrant inspection far more often, and one that looks like jewelry when the amps and travel speed are right.
Heat control is the other half. A foot pedal or fingertip amperage control lets the welder ramp heat up and down mid-bead, taper off at the crater, and feather the current across a thin edge without blowing through. That is exactly why thin-gauge work lives in TIG territory — our guide to TIG welding sheet metal walks through settings and blow-through prevention for exactly this reason.
DC electrode negative concentrates heat into the work and gives deep penetration on steel and stainless. DC electrode positive is rarely used alone because it burns the tungsten, but it is the cleaning half of AC. AC alternates between the two, which is why it is the standard choice for aluminum: the positive half breaks up the tenacious aluminum oxide layer while the negative half does the melting.
Tungsten selection matters too. Thoriated tungsten (the red-banded 2% thoria type) holds a sharp point and starts easily, but it is mildly radioactive, and the dust from grinding it is the real hazard — collect it, don’t breathe it. Ceriated and lanthanated tungsten perform nearly as well without the radioactivity concern.
Quick Note — TIG vs. MIG at a Glance:
Many shops keep both, which is why MIG/TIG combo welders are so popular.
Aerospace tubing, food-grade stainless sanitary lines, aluminum bicycle frames, nuclear orbital welds, and thin sheet all default to GTAW. AWS standard welding procedure specifications reflect that pedigree, specifying GTAW with ER70S-2 or ER70S-3 filler for carbon steel sheet and ER3XX filler for stainless, including consumable-insert root joints used on military work. If you have seen the process spelled differently, “wig welding” is simply the same thing.
TIG is slow, the machines cost more, and the skill floor is high — you need two coordinated hands and real patience. It is also unforgiving of contamination: oil, mill scale, or a stray breeze of shop dust will wreck a bead. Deposition rate is the lowest of the major arc processes, so nobody runs TIG on a long, thick production seam.
What it delivers in exchange is control. That is why inspectors tend to prefer TIG for root passes on critical pipe and pressure work — a smooth, fully fused root with no slag to trap makes radiographic and visual acceptance far more predictable, which is the entire point of formal pipe welding procedures. And on the health side, it is the quiet winner: in NIOSH’s field study, GTAW produced the lowest measured fume exposure at 46–77 µg/m³, largely because the welder’s head is not sitting in the plume. You still dress for the job — our welding PPE guide covers the gloves and shade you will want.
When the job calls for laying down a massive amount of weld metal in the harshest conditions, the “big five” arc processes often give way to two true powerhouses. Both MIG welding and stick welding have their place, but Flux-Cored Arc Welding (FCAW) and Submerged Arc Welding (SAW) were engineered specifically for speed, penetration, and brute productivity. These two processes are the go-to choices for heavy structural, shipbuilding, and pressure vessel work across the industry.
Dating back to the 1950s, FCAW emerged as an evolution of SMAW and an alternative to GMAW. The goal was simple: combine stick welding’s self-shielding field capability with MIG’s continuous wire feed. This innovation allowed welders to gain the portability of stick, while drastically increasing deposition rates over a traditional electrode. As a result, FCAW quickly cemented itself as a staple for outdoor and structural jobs.
Quick Note: The EPA AP-42 reports that FCAW accounted for 17% of electrodes consumed by process type, showcasing its widespread use throughout fabrication shops.
FCAW is split into two distinct variations based upon its shielding method:
When it comes to filler metal classifications, AWS SWPS list common wires such as self-shielded E71T-8 and E71T-11, as well as gas-shielded E70T-1 and E71T-1 for carbon steel ranging from 1/8 in. to 1-1/2 in. It’s important to note that FCAW is limited to uphill progression only in the vertical position. With practice utilizing flux core wire welding tips, these wires can produce higher deposition and penetration than GMAW, all whilst combating the elements.
If FCAW is powerful, Submerged Arc Welding is unmatched in pure productivity. As described by NRC training materials, SAW utilizes a continuously fed metal electrode with granular flux shielding, where the arc is completely submerged and not visible to the user. This unique trait not only protects the operator from the arc flash, but also allows for immense amperages to be ran without the same level of spatter.
Due to the sheer heat input, SAW is almost exclusively utilized for long, flat welds on plate, pipe, and heavy fabrication. Automatic or traveling carriage setups are the industry standard, allowing for extremely high deposition rates on large components. These attributes are why it is heavily relied upon for pipe welding procedures, ship hulls, and structural girders. The EPA AP-42 notes SAW accounted for 4% of electrodes consumed by process type, a smaller percentage, but one that represents some of the largest welds being deposited in the world.
Note: SAW should never be used out of position. Its positioning limits are strict due to the fluidity of the molten slag and weld pool. For any vertical or overhead work, processes such as overhead stick welding will prove far more viable.
With great power comes great responsibility, especially in post weld cleanup. Both processes rely heavily on slag management, as the flux forms a solidified slag layer that must be chipped and brushed between passes to prevent welding defects such as slag inclusions. For multi-pass welds, this is a necessity to ensure proper fusion.
When looking into the emission profile of each, the particulate matter produced is incredibly fine. NIOSH measured median particle diameters of 352 nm for FCAW versus 149 nm for GMAW. These submicron particles can be easily inhaled, making proper ventilation and utilizing the correct welding PPE an absolute must for any operator.
Whether you’re tackling a windy structural repair or running miles of seam on heavy plate, FCAW and SAW provide the power at speed that shop and field fabricators rely on. By understanding their differences, positioning limits, and safety requirements, you can utilize these workhorses to their maximum potential.
Stick, MIG, TIG, flux-core and submerged arc cover the lion’s share of real-world work, but stop there and you will misread job postings, shop capability lists and repair-shop signs. The welding universe is wider: flame processes, constricted-arc processes, and a solid-state tier that never melts the base metal at all. Knowing roughly where each one fits turns a five-process vocabulary into an actual map of the trade.
Oxy-fuel is what people picture when they say “torch welding.” OSHA describes gas or oxy-fuel welding as using a flame produced by burning a gas, usually acetylene, and notes it is still commonly used for welding iron, steel, cast iron and copper. A neutral oxy-acetylene flame runs near 5,700°F at the tip, enough to puddle mild steel while the flame itself shields the weld zone from oxygen.
Its real strength is versatility. The same torch welds, heats, bends, straightens, shrinks, brazes and cuts, and it needs nothing but two cylinders and a striker — no electricity, no wind-sensitive gas cup. That is why an oxy-acetylene rig still rides on farm trucks, in maintenance shops and on pipeline crews. The trade-offs are a wide heat-affected zone, slower travel, more distortion on thick material, and cylinder handling risks that demand flashback arrestors, regulators and proper storage.
Note: Thermit welding is a different animal entirely — OSHA points out it runs on a chemical reaction rather than gas or electric current. It is the aluminothermic process that joins railroad rail in the field, and we break down how it works in Railroad Thermite Welding: How Aluminothermic Rail Joining Works.
Plasma welding pushes the arc through a small constricted nozzle, producing a stiff, high-velocity jet instead of a soft cone. According to the Nuclear Regulatory Commission’s plasma arc welding overview, that constriction delivers higher energy density, increased penetration and faster travel speeds — and, importantly, it requires less welder skill than GTAW to produce a sound bead.
Most readers meet plasma on the cutting side. A plasma cutter arcs through compressed air to slice conductive metal — mild steel, stainless, aluminum, copper — faster than an oxy-fuel torch and without relying on an oxidation reaction, which is why it cuts non-ferrous plate that oxy-fuel simply cannot.
| Process | Heat source | Where you’ll see it | Watch out for |
|---|---|---|---|
| Oxy-fuel | Burning acetylene flame | Field repair, brazing, heating, cutting | Cylinder safety, wide HAZ |
| Plasma | Constricted arc + gas jet | Cutting, thin stainless fabrication | Nozzle/consumable wear |
| Laser | Concentrated light | Robotic sheet metal, handheld fab | Reflected radiation, eye safety |
| Electron beam | Electrons in vacuum | Aerospace, nuclear, tooling | Vacuum chamber cost, X-rays |
| Friction stir | Mechanical friction | Aluminum aerospace, rail, EV packs | Heavy fixturing, joint geometry |
| Resistance/spot | Resistance at contact | Automotive body lines, appliances | Electrode wear, shunting |
Laser welding concentrates light into a spot measured in fractions of a millimeter, giving deep penetration with very little heat input. The American Welding Society reported in March 2025 that some handheld laser welding systems are claimed to weld up to four times faster than gas tungsten arc welding, with minimal preparation and post-finishing. That combination is why handheld laser units are showing up in sheet-metal shops and why the process keeps surfacing in discussions about closing the labor gap.
Electron beam welding fires electrons at the part inside a vacuum chamber. No atmosphere means no oxidation, and the energy delivers very deep, narrow penetration with a slim heat-affected zone — ideal for aerospace, medical implants and nuclear hardware, though chamber cost and X-ray shielding limit it to specialists.
Friction stir welding skips melting altogether. A rotating tool plows along the joint, mechanically stirring the material into a solid-state bond. The result is weldable aluminum alloys that fusion processes crack on, near-zero fume, and joints aerospace and rail builders trust for fuselage panels and carbody sections. The limits are fixture weight and geometry: it likes straight butt and lap joints.
Resistance and spot welding deserve a mention too: heat comes from electrical resistance at the contact point while electrodes squeeze the sheets together, which is why every automotive body panel and appliance shell is built that way. Curious about the parameters behind copper joints? See Spot Welding Copper: A Practical Guide to Parameters & Process Control.
These are not fusion welding. OSHA defines brazing as a metal-joining process in which only the filler metal is melted — unlike fusion welding, where the base metal melts too. The filler is drawn into a tight gap by capillary action. Brazing filler flows above roughly 840°F (450°C); soldering works below that, which is why solder joins copper pipe, electronics and tinware without softening the parent metal.
Quick Note: Why should an everyday reader care about the processes outside the big five? Because that squeaky gate, cracked exhaust flange or aluminum trailer panel will land on your bench with the question already answered — you just have to recognize which process the job is actually asking for. Oxy-fuel for heat and brazing, plasma for clean cuts, spot for sheet, laser for speed, TIG where appearance matters (see The Complete Guide to TIG Welding Sheet Metal). Knowing the options exist is half of choosing correctly, and every one of them still demands the right eye, skin and respiratory protection described in What Does a Welder Wear? The Complete Welding PPE Guide.
Now we get to the question readers actually type into Google: which one should I use? Process selection isn’t a personality test. It’s an engineering decision built on a handful of variables that never change, no matter what machine sits in your garage.
Welding engineers run through the same checklist whether they’re specifying a pipeline tie-in or a garden gate:
That last point deserves emphasis. AWS Standard Welding Procedure Specifications (SWPS) are indexed by base metal, thickness, process, filler metal, and condition — the exact decision variables listed above. When a code-controlled job tells you the process, the argument is over.
| Process | Best At | Weak At |
|---|---|---|
| SMAW (Stick) | Field work, wind, dirt, all positions, thick steel | Thin sheet, high-speed production |
| GMAW (MIG) | Clean shop production, thin-to-medium steel, speed | Outdoor wind, dirty metal |
| GTAW (TIG) | Precision, cosmetics, stainless, aluminum, root passes | Speed, deposition, beginners outdoors |
| FCAW | Heavy structural, windy sites, high deposition | Cosmetic work, positional limits |
| SAW | Long flat seams, thick plate, max deposition | Any out-of-position work |
| Oxy-fuel | Brazing, heating, bending, repair | Structural fusion welding today |
Note the positional detail on FCAW, because it surprises people: per AWS SWPS notes, FCAW in the vertical position is limited to uphill progression, while downhill progression is allowed on the root pass only. Position doesn’t just influence technique; it can dictate whether a process is even permitted.
Scenario 1: A cracked trailer frame in a driveway. Wind is blowing, the steel has road grime and paint, and you’re welding vertical and overhead on a repair that must hold a highway load. Gas-shielded MIG is a bad bet here. Stick welding with a 7018 electrode is the classic answer — self-shielded, all-position capable, tolerant of imperfect prep. A 3/32 rod works for smaller trailer tubing; step up to 5/32 for heavier frame members. For a beginner, self-shielded flux-core wire on a multi-process machine is the modern compromise: stick’s wind tolerance with wire-feed convenience.
Scenario 2: A stainless handrail for a restaurant. The weld is the product. You need clean, silver, pickled-ready beads on thin stainless tube, indoors, in a shop or quiet jobsite. This is TIG’s home turf — inert argon shielding, precise heat control, proper technique on thin sheet, and filler like ER308L. MIG with tri-gas and a pulsed-spray setup can work for longer runs if throughput matters, but for a short, visible, food-grade handrail, TIG wins.
Flat position, thick material, hundreds of feet of weld, and an inspector with a checklist. You want maximum deposition in minimum passes: dual-shield FCAW or, for the longest runs, an automatic submerged arc carriage. The root and critical passes may still be stick or TIG depending on the WPS — as covered in pipe welding procedures, position and pass sequence drive the specification.
Quick Note: Dirty metal outdoors? Stick. Clean shop production? MIG. Visible or critical weld? TIG. Heavy structural in wind? Flux-core. Long flat seams on plate? Submerged arc. Need one machine for everything? A MIG/TIG combo welder covers most garage work — just know where each process stops being appropriate.
One more reality check: the labor market rewards flexibility. Per AWS data, 61% of welders work in manufacturing, followed by specialty trade contractors at 8% and repair/maintenance at 4%. AWS Welding Digest job-posting analysis shows welding as the most-listed skill, with postings frequently naming specific processes like MIG and TIG. Knowing how to choose the process — not just run it — is what turns a button-pusher into the person who signs the repair card.
Process selection is usually framed as a quality or cost decision. It is also a health decision. The fume plume coming off a stick arc is not the same chemistry as the thin wisp off a TIG arc, and over a 30-year career that difference compounds. If you teach people one thing about welding hazards, teach them this: the process you pick determines what you breathe.
Welding fume is a复杂 mix of ultrafine metal oxides, silicates, and gases generated when the electrode, filler, base metal, coatings, and flux are vaporized by arc heat. The exact recipe changes with the process:
Quick Note: Process choice changes exposure dramatically. If a shop can choose GTAW over SMAW for thin stainless, the fume reduction is immediate and measurable. If it must use flux-core, ventilation and respiratory protection are non-negotiable.
Acute exposure produces metal fume fever: fever, chills, nausea, and chest tightness, classically a Monday-morning complaint after a weekend of galvanized or stainless work. It usually passes in 24 to 48 hours, but recurring episodes are a warning sign, not a badge of honor.
Chronic exposure is the real concern. OSHA warns that prolonged fume exposure may cause lung damage and cancers of the lung, larynx, and urinary tract, and that manganese fume can produce Parkinson’s-like symptoms — tremor, slowed movement, and cognitive changes that mimic the disease itself.
The evidence has only hardened. A 2019 meta-analysis in Occupational and Environmental Medicine found welding fume increases lung cancer risk regardless of steel type and independent of smoking or asbestos exposure. NIOSH’s criteria document goes further, concluding welders generally have a 40% increase in relative risk of developing lung cancer from their work — with excesses appearing even below OSHA’s permissible exposure limits. Welding fume is now classified by IARC as a Group 1 possible human carcinogen.
Stainless welders carry an extra hazard: hexavalent chromium. OSHA’s PEL for hexavalent chromium is 5 µg/m³ as an 8-hour time-weighted average under 29 CFR 1910.1026 and 1926.1126. That limit is low enough that a modest local exhaust failure puts you over it.
Argon and helium are heavier than air and pool in pits, tanks, and trenches. CO₂ displaces oxygen and accelerates breathing. A TIG bottle left flowing in an unventilated enclosure can drop oxygen to lethal levels without any warning odor. Confined-space welding requires continuous atmospheric monitoring, a retrieval plan, and — for gas line and purge work — strict inerting protocols.
29 CFR 1910.252, the welding, cutting, and brazing standard, requires local exhaust or general ventilation sufficient to keep toxic fumes, gases, and dusts below the maximum allowable concentrations in 29 CFR 1910.1000. Around it sit a stack of process-specific obligations:
Quick Note — Shop Ventilation & PPE Checklist:
Treat process choice as risk engineering. The cleanest arc you can legally run is usually the safest one to stand behind for the next thirty years.
You’ve now seen the whole map: stick, MIG, TIG, flux-core, submerged arc, and the specialty processes beyond them. But knowing the processes isn’t the same as choosing correctly under pressure. Most bad welds aren’t really welds problems at all. They’re selection problems. Here are the mistakes that cost real money, and how to avoid each one.
Quick Note: Before choosing a process, write down five things: base metal and thickness, welding position, shop or field, cleanliness of the joint, and the code or inspection standard. Those five answers usually pick the process for you.
The trade is changing fast, but not in the way headlines suggest. Robotic and automated welding systems are becoming standard in production work, yet AWS workforce data notes welders remain essential in hybrid roles that combine hands-on skill with programming, calibration, and robot oversight. Handheld laser welding is the other big shift; AWS reports it can weld up to four times faster than GTAW, helping ease the labor gap. AI-assisted parameter setting is quietly appearing in mid-range machines too, recommending voltage and wire speed from material thickness.
The practical takeaway? Learn a manual process deeply, then layer programming literacy on top. A welder who can troubleshoot a robotic cell or dial in a MIG-TIG combo machine is nearly unemployable in a bad way — meaning they never stay unemployed.
AWS estimates 771,000 U.S. welding professionals as of 2025, with more than 157,000 nearing retirement. AWS projects 320,500 new welding professionals will be needed by 2029, averaging roughly 80,000 openings per year between 2025 and 2029. The BLS projects 2% growth from 2024 to 2034, with retirements driving most openings. Median pay sits around $55,600 annually, or $26.76 per hour. This is a field with more demand than people, and multi-process welders command the top of that range.
That contractor with the $14,000 failure had capable hands and a competent crew. What he lacked was a process-selection framework. With the steps above, you won’t just weld better — you’ll weld right the first time, which is the only kind of economy that actually holds up. For code-driven work like pipe, our pipe welding procedures guide shows how the framework maps onto real WPS documentation.
The five processes you’ll encounter most are shielded metal arc welding (SMAW/stick), gas metal arc welding (GMAW/MIG), gas tungsten arc welding (GTAW/TIG), flux-cored arc welding (FCAW), and submerged arc welding (SAW). Oxy-fuel welding and plasma cutting round out the everyday list.
GMAW (MIG) is generally the easiest because the wire feeds automatically, the arc is stable, and there’s no slag to chip. Most beginners lay usable beads in an afternoon, though the tradeoff is that MIG is less forgiving of dirty, rusty, or out-of-position joints than stick.
Strength depends far more on joint design, electrode classification, and weld quality than on the process itself. That said, processes with deep penetration and full fusion — such as SAW on heavy plate or a properly executed 7018 stick root — routinely produce full-strength code-compliant joints.
MIG uses a continuously fed consumable wire electrode and shielding gas for speed and ease, while TIG uses a non-consumable tungsten electrode and a separate filler rod for precision and clean, cosmetic welds. MIG is roughly 3–5 times faster on most joints; TIG wins on thin material, aluminum, and visible seams.
Gas-shielded processes like GMAW and GTAW lose shielding gas in wind above roughly 5 mph, so outdoor work favors self-shielded FCAW or stick welding. Stick is the classic choice for field and pipeline work because the flux coating provides its own shielding.
OSHA lists arc welding processes in decreasing order of fume production with FCAW and SMAW at the high end and GTAW at the low end. Stainless work with any process adds hexavalent chromium, regulated by OSHA at a 5 µg/m³ 8-hour TWA, and NIOSH links welding fume to a 40% higher lung cancer risk.
Not really — what people call gasless MIG is actually self-shielded flux-cored welding (FCAW-GS), where the flux inside the tubular wire generates its own shielding. It’s a distinct process with different settings, wire, and spatter behavior than conventional GMAW.
Usually yes. AWS job-posting data shows welding is the most-listed skill in postings and that many employers specifically request MIG and TIG capability. Being competent in stick plus at least one wire process makes you viable across manufacturing, structural, and repair work.
EPA reports more than 80 different welding operations in commercial use, including arc, oxyfuel, brazing, soldering, and thermal cutting. But roughly a dozen processes cover the overwhelming majority of day-to-day industrial work.