MM Welding Explained: What It Is, How It Works, and How to Do It Right

A fabricator once told me he lost a ₹40,000 gate job because one vertical seam cracked open three days after installation — the welder had dialed the amperage by ‘feel’ and never checked the electrode’s recommended range. MM welding (manual metal arc stick welding) is the most forgiving, cheapest, and most portable process in the world, yet it is still the one people fail at most often, simply because nobody taught them the numbers behind the arc.

Introduction: Why MM Welding Still Runs the World

When the gas runs dry and a deadline is closing in, most fabricators fall back on the same solution they have relied on for nearly a century: a stick welder. No gas bottles, no compressors and very little to go wrong. It is the process that builds bridges in the rain, repairs farm equipment in a field, welds pipe in a trench and holds together the rail lines that carry freight across continents. Despite the rise of cleaner, faster processes, it refuses to go away. If you are searching for “MM welding,” you are looking into the trade’s most enduring workhorse.

So What Does “MM Welding” Actually Mean?

Much of the confusion around the name comes down to geography. MM welding stands for Manual Metal Arc welding, abbreviated MMA or MMAW in international standards. In American Welding Society terminology, the same process is called Shielded Metal Arc Welding (SMAW). Out on the job, welders simply call it stick welding, as the electrode is a consumable stick coated in flux that shields the arc by itself.

All three refer to the exact same process. A UK job posting for an MMA welder, a U.S. structural shop requiring an SMAW-qualified hand or a contractor asking for “a stick man” are all talking about striking an arc with a flux-coated electrode.

Who Is This Guide For?

This guide is built for anyone who needs to lay a weld that will hold. That can mean very different things, but the fundamentals are the same. Whether you’re just getting started or returning to the process after years away, these are the people it was written with in mind:

• Beginners and DIYers: Those who have bought a cheap stick welder and are tired of porosity, stuck rods and blown-through corners.
• Apprentices and trade students: Those preparing for welder performance qualification tests or coursework that need the numbers, not guesswork.
• Fabricators and maintenance welders: Those who usually MIG, but need to go stick when the work moves outdoors, underground or onto dirty steel.
• Hobbyists and artists: Those who opted for stick as the cheapest real machine they could afford and want to use it properly.

What This Guide Covers

Rather than skimming the surface, this is a start-to-finish manual for the process. We will cover how the arc and flux coating work, the equipment you actually need (and what you can skip), and the parameters that separate a solid weld from a failed one: amperage, arc length, rod angle, polarity and travel speed. From there, we will explore why stick welding feels so hard at first and how to break through it, the four welding positions, how to size a fillet weld in millimeters, the industries where stick still dominates, common mistakes and their fixes, an honest comparison with MIG and TIG, and the safety, fume and certification rules that keep you employable.

Why the Stakes Are Real

The demand for skilled welders is not fading. The American Welding Society estimates roughly 771,000 welding professionals were employed in the United States as of 2024–2025, and AWS projections point to approximately 330,000 additional welding professionals needed by 2028 to replace retirements and fill new roles created by infrastructure and manufacturing growth. Meanwhile, the U.S. Bureau of Labor Statistics projects employment of welders, cutters, solderers, and brazers to grow about 2% from 2025 to 2035 (BLS Occupational Outlook Handbook). These figures, drawn from AWS workforce data, show steady demand with pay that follows skill.

Those numbers matter on the shop floor. A weld can look passable to an untrained eye, but without the right amperage, arc length or care for your electrodes, its strength can drop drastically. The difference between a weld that fails under load and one that outlasts the steel around it comes down to precision, not luck.

By the end of this guide, you will have the facts, figures and techniques to get there. Let’s get to work.

What Is MM Welding? Definition, Full Name, and How the Arc Works

If you have ever searched for “MM welding” and landed on three different names for the same thing, you are not confused — the industry genuinely uses several labels for one process. Here is the plain version: MM welding is Manual Metal Arc welding, a stick process where an electric arc melts a flux-coated consumable electrode and the base metal together. The AWS term is Shielded Metal Arc Welding (SMAW), and most tradespeople simply call it stick welding.

Why So Many Names for One Process?

The naming split is mostly geographic and historical:

• MM / MMA / MMAW — Manual Metal Arc (Welding), common in the UK, Europe, Asia, and Australia.
• SMAW — Shielded Metal Arc Welding, the official AWS classification used in American codes and procedures.
• Stick welding — the shop-floor name everywhere, because the electrode looks like a coated stick.

All three mean the same thing: you strike an arc with a coated rod, the arc does the melting, and you finish with a stick of filler metal that shrinks as you go. If you are reading procedure documents, note that AWS D1.1 and similar codes will say SMAW, while a British or Indian drawing may say MMA. Same process, different paperwork. For a quick sanity check on how other processes compare by name and physics, our guide to how a spot welder works walks through the same kind of naming logic.

How the Arc Actually Works

The science is simpler than it sounds. An electric arc forms between the electrode tip and the workpiece, reaching temperatures high enough to melt steel. As the flux coating on the rod heats up, it does three jobs at once:

1. It decomposes into shielding gas that blankets the molten puddle and keeps oxygen and nitrogen out. Those gases are what cause porosity — the tiny bubbles that ruin a weld.
2. It forms a liquid slag that floats on top of the puddle, protecting it as it cools. You chisel that slag off after the pass.
3. It cleans and stabilizes the arc, adding ionizable compounds that keep the arc easy to restart and steady to run.

A stick electrode effectively has four stages in its working life: ignition (striking and establishing the arc), arc length (the gap you maintain while running), metal transfer (droplets crossing the arc into the puddle), and extinction (pulling away at the crater). Nearly every beginner defect traces back to one of those four moments.

The Four Rods You Will Meet First

Two rules cover most situations. E6013 is where beginners start because it runs smoothly on AC or DC, wants a short arc, and leaves a clean-looking bead. E7018 is the structural rod — low hydrogen means stronger, tougher welds, but the coating must stay dry, which is why welders store it in heated rod ovens. We break this down further in what electrodes are in welding: types, numbers, polarity, and how to choose, and you can see exact dial settings in our 3/32 E7018 amperage guide.

The flux chemistry also explains the safety side. Burning coating produces fumes, which is why ventilation and PPE come with the process from day one — see our complete welding PPE guide before you strike your first arc.

Once you understand that a stick electrode is a gas generator, a slag maker, and a filler wire all in one, the rest of this article — settings, angles, weld sizing, and inspection — starts to click. That coating is doing four jobs at once, and your technique exists to let it do them properly.

MM Welding Equipment: What You Actually Need to Start

Here’s the good news about MM welding: the barrier to entry is genuinely low. A decent stick setup costs less than a quality MIG rig, fits in the back of a car, and doesn’t need bottled gas. The bad news is that beginners routinely blow their budget on the wrong machine and then wonder why their welds look like bird droppings. So let’s build the kit list in the order that actually matters.

The Machine: Transformer or Inverter?

An MM welder is fundamentally a constant-current (CC) power source. You have two flavours:

• Transformer machines are the old workhorses — heavy, simple, nearly indestructible, and usually AC-only or AC/DC at best. A 230 V transformer unit might weigh 25–30 kg and put out a smooth arc, but it drinks electricity and takes two hands to carry.
• Inverter machines use electronic switching to produce the same output at a third of the weight, with far better arc starts, finer amperage dialing, and often DC output on a 110 V outlet. For a beginner in 2026, an inverter is the sensible default.

Buy more amps than you think you need. An entry-level inverter rated 180–200 A will handle everything from 3 mm sheet work up to structural plate with a 3/8 in. (9.5 mm) rod. For a home shop, a 200 A inverter covers about 90% of jobs; industrial CC machines only make sense for fabrication shops running long shifts. If you’re curious how other processes stack up on setup, our MIG welder setup guide walks through the same buying logic.

AC, DC, DCEP, and DCEN: What Your Machine Must Do

Polarity decides how heat is distributed between the rod and the plate:

• DCEP (DC electrode positive) puts roughly two-thirds of the heat at the electrode, giving deep penetration. This is the default for 7018 and 6013 work.
• DCEN (DC electrode negative) drives heat into the workpiece, producing a fast, shallow, hot bead — used for gouging and some corner work.
• AC alternates polarity 100+ times a second, which cancels arc blow — the magnetic wander you get on grounded or positional welds — and lets you run basic 6011 and 6013 rods on the cheapest machines.

Rule of thumb: buy an AC/DC machine. E6010 only runs on DC, E7018 runs best on DC (though AC-rated 7018s exist), and 6011/6013 run on anything. Our full electrode selection guide decodes which rod suits which job.

Cables, Holder, Ground, and Consumables

Cable size matters more than people admit. Use 2/0 (35 mm²) welding cable for runs over 3 m at 200 A; undersized cable turns into a heater and drops your arc voltage. Cam-lock connectors let you swap leads quickly and fix a bad cable without replacing the whole set. Buy an electrode holder rated above your machine’s output, and a ground clamp with real copper braid — not painted steel.

Post-weld kit: a spring chipping hammer, a stiff wire brush, and an angle grinder with a flap disc. Then personal protection: an auto-darkening helmet (shade 9–13), a leather jacket, gauntlet gloves, and steel-toe boots. We break the full checklist down in our welding PPE guide. Finally, the workspace: concrete or dirt floor, no paper or solvents within 10 m, a fire extinguisher within arm’s reach, and ventilation — the OSHA welding fume fact sheet recommends local exhaust or at minimum keeping your head out of the plume.

Electrode Storage: The Silent Weld Killer

E7018 is a low-hydrogen rod, and its flux coating is hygroscopic. Leave a carton open in a humid shop overnight and you’ve bought yourself porosity and hydrogen cracking. AWS A5.1 specifies absorption limits and re-drying temperatures around 300–350°C for rebaking — which is why production shops keep rod ovens at roughly 120–150°C. At home, seal opened rods in their original packaging, then drop them in an airtight container with silica gel packs. 6010 and 6013 are far more forgiving; 7018 is not.

Amps to Start With

As a baseline, a 3/32 in. (2.4 mm) 7018 runs around 60–90 amps, while a 1/8 in. (3.2 mm) 7018 typically needs roughly 100–130 amps. We’ll dial exact settings in the next section, but set your machine near the middle of that range and adjust by reading the puddle.

Settings and Technique: Amperage, Arc Length, Travel Speed, and Rod Angle

Almost every bad stick weld traces back to four variables: how much current is in the arc, how far the rod sits from the plate, which way it points, and how fast it moves. Get those four right and even a budget inverter lays a bead that looks machine-made. Get them wrong and no rod, no grinder, and no hope will rescue the joint.

Amperage: Start With the Math, Then Adjust by Eye

The trade’s simplest rule of thumb is one amp per 0.001 in. of electrode diameter. A 1/8 in. rod (0.125 in.) gets a baseline near 125A. A 5/32 in. rod starts around 160A, and a 3/32 in. rod lands near 90A before fine tuning. From there you adjust for position and material: shave 10 to 15 percent off for vertical and overhead work, drop further on thin sheet, and nudge upward on heavy plate in flat position where the puddle sits still.

Two references worth keeping open while you dial in: 3/32 E7018 Amperage: Settings, Polarity & How to Run It for light structural work, and 5/32 E7018 Amperage: Settings, Polarity & Technique when you step up to heavier passes. If the digits on the rod wrapper still look like a secret code, What Are Electrodes in Welding? Types, Numbers, Polarity & How to Choose decodes them end to end.

Arc Length: The Gap You Cannot See

Keep the arc length roughly equal to the core wire diameter of the electrode: about 3 mm for a 1/8 in. rod, closer to 2 mm for a 3/32 in. rod. Push the rod in as it burns so the gap never grows. A tight arc crackles steadily; a long arc roars, spits, and wanders. When the gap opens, flux shielding breaks down, nitrogen gets into the melt, and you end up with porosity, spatter, shallow penetration, and undercut at the toes. A long arc also throws more fume into your breathing zone, which is why OSHA’s welding fact sheet puts ventilation first in any shop.

Rod Angle and Travel Speed

The work angle is how far the rod leans sideways against the joint; the travel angle is how far it leans away from the direction of travel. For a fillet or butt in flat and horizontal positions, use a slight 10 to 15 degree drag that splits the joint. Vertical-down flips the approach: you push, usually with 6010 or 6011 on thin material, so the puddle cannot run ahead of the arc. Vertical-up is standard for 7018 structural fillets and grooves, where slow upward progression delivers the penetration and side-wall fusion an inspection demands. Push or Pull Stick Welding: Which Technique Is Right and Why covers that trade-off.

Travel speed has to match the deposition rate: move too slowly and the rod piles up into a tall, narrow crown; move too fast and you get a thin, humped bead with cold edges. When settings and speed are right, the puddle is about one to one and a half electrode diameters wide, with the toes wetting flat into the plate. Overhead work tightens every rule further, which is covered in Overhead Stick Welding: The Complete Guide to 4F & 4G Technique, Amperage, and Rod Selection.

Polarity: DCEP, DCEN, or AC

• DCEP (reverse polarity) concentrates heat at the work and drives the deepest penetration. It is the default for E7018, E6010, and most structural groove welds.
• DCEN (straight polarity) puts more heat into the rod. It is the choice for aggressive gouging, corner joints, and thin material where you are fighting burn-through rather than chasing penetration.
• AC is the compromise: it handles arc blow when magnetic fields pull your arc sideways near heavy or odd-shaped steel, and it is the only option on old transformer-only machines. Rods like 6011 and AC-rated 6013 are built for it.

Troubleshooting: Read the Bead, Then Change One Dial

Note on striking the arc: two methods work. Scratch start is like lighting a match: drag the rod across the plate and lift into position. Tap start is a quick jab straight down and up, cleaner in tight joints. Whichever you use, strike on the plate, never on a grounding clamp, and if the rod sticks, twist it free immediately or unclamp the holder first.

Change one variable at a time. Every adjustment shows up in the next two inches of bead, and reading that feedback loop is how beginners become welders.

Positions, Joint Types, and Weld Size in Millimeters (mm)

Half the people who search “MM welding” are not asking about the process. They want to know how many millimeters a weld should be. Either way, a weld is only as good as its size, its position, and the joint it sits in. Here is how to read the numbers on a drawing and put metal where the engineer intended it.

The Four AWS Welding Positions

AWS position codes pair a number with a letter. The letter names the joint type: F for fillet (T, lap, or corner joints) and G for groove (butt joints). The number names where the weld sits in space:

• 1F / 1G — Flat: the puddle sits on top of the joint and gravity helps you. This is the easiest position and where every beginner starts.
• 2F / 2G — Horizontal: welding along a horizontal line on a vertical or angled surface. The puddle wants to sag, so travel speed and angle matter more.
• 3F / 3G — Vertical: welding up or down a vertical seam. Vertical-up gives deeper penetration; vertical-down is faster and common on thin sheet.
• 4F / 4G — Overhead: welding from below with the puddle hanging overhead. It is the hardest position in stick welding and requires dropping your amperage roughly 10–15% below your flat setting so the molten metal does not sag and drip. Our Overhead Stick Welding: The Complete Guide to 4F & 4G Technique, Amperage, and Rod Selection breaks down rod choice and body position for this work.

Pipe work adds its own set: 1G through 6G, with 6G the industry benchmark for qualification testing because the pipe sits at a 45° angle and forces you through every position in one weld. The Pipe Welding Procedures: The Complete Guide to WPS, Positions, Passes & Inspection walks through how those positions appear in real written procedures.

The Five Common Joint Types

Leg Size vs. Throat: The Math That Governs Strength

A fillet weld is measured two ways. The leg is the distance from the joint root to the toe of the weld, along the face of the plate. The throat is the shortest distance from the root to the face — the narrowest cross-section and the one that actually carries the load. For a standard 45° fillet with equal legs:

Effective throat = 0.707 × leg size

So a 6 mm leg delivers only about 4.24 mm of throat. This is the single most common misunderstanding in fabrication: a weld that looks like 6 mm on the surface is carrying 4 mm of metal. To get a 6 mm throat, you need roughly an 8.5 mm leg. Designers size welds by throat because the penetration into the joint root and throat area determine strength, not the visible bead width. Plate thickness and the loads the joint will see drive the required size; heavier, dynamically loaded joints need more throat, not just a pretty bead.

Three Practical Projects, Three Sets of Numbers

• 6 mm mild steel butt joint: a 3.2 mm electrode at roughly 110–125 A, run as a 2-pass single-V groove with a small root gap. One pass will not give you the throat you need on a V-groove.
• 5 mm sheet lap weld: a 2.5 or 3.2 mm rod around 90–110 A, a small fillet on both sides of the overlap rather than one oversized bead.
• 3 mm thin sheet: drop to a 2.0–2.5 mm electrode at about 60–80 A and keep travel moving. See Stick Welding Sheet Metal: Amperage, Rod Choice, and Blow-Through Prevention for the full settings range.

How to Measure a Weld with a Fillet Gauge

A fillet gauge set costs very little and settles arguments instantly. Open the gauge for your target leg size, hook it into the joint, and read the throat mark. Check three things: both legs are roughly equal, the face is slightly convex or flat (never concave at the toe), and the gauge sits flat without rocking. Watch for undercut at the toes and fusion failure at the root — a gauge will show both if you look for them. Measure the weld you have, not the weld you meant to make.

Where MM Welding Is Used: Industries, Jobs, and Real Applications

Ask ten people where welding happens and most will say \”a factory.\” The truth is far wider. Manual metal arc welding shows up wherever steel has to be joined away from a clean, climate-controlled bench: bridges, shipyards, pipeline rights-of-way, farms, and the gates and railings of houses built this year.

The Big Industries That Run on Stick Electrodes

The heaviest users of SMAW are the sectors that move and hold massive steel:

• Structural steel and bridges. Beams, columns, base plates, and field splice connections are routinely welded with stick electrodes, often in the open air and sometimes overhead. Pipe welding procedures and structural codes go hand in hand here, since a bridge weld is inspected against a written procedure, not a guess.
• Pipelines. Tie-ins, repair sections, and remote welds on cross-country lines are classic SMAW territory. A crew walks onto a right-of-way with a diesel-driven stick machine, a bundle of rods, and a generator. No gas bottle has to be trucked in. That same logic governs gas line welding, where codes and purging rules cover every pass.
• Shipbuilding, ship repair, and offshore work. Hull sections, deck structures, and repair welds on rigs are frequently stick-welded because the process tolerates wind, moisture, and imperfect fit-up.
• Pressure vessels and heavy fabrication. Thick-wall vessels, tanks, and heavy equipment housings often start with stick root passes before other processes finish the job.
• Maintenance, repair, and overhaul. Broken hinges, cracked frames, worn buckets, and snapped brackets, anywhere from a shop floor to a construction site.
• Fabrication for everyday life. Fences, gates, railings, stairs, fire escapes, and structural supports are bread-and-butter stick work. So is metal art and sculpture, where the raw bead is part of the aesthetic rather than a defect.

Why Stick Welding Owns the Outdoors

It comes down to one design feature: the flux coating. Shielding-gas processes like GMAW push a cloud of argon or CO₂ around the arc, and that cloud blows away in even a light breeze, leaving the weld porosity-riddled. As TWI explains of MIG welding, gas shielding is a genuine limitation outdoors. A stick electrode generates its own protection: the flux decomposes into shielding gas and a slag blanket right at the arc. Wind tolerances are dramatically higher, the equipment is a single portable box, and the arc will happily burn on rusty, dirty, or painted metal that would make a MIG gun spit and sputter.

SMAW is also an all-position process. With the right rod and technique, a welder can work flat, horizontal, vertical, and overhead, which is why overhead-heavy work like overhead stick welding still gets specified on site rather than rotating a 40-ton structure.

Three Situations Where Stick Is the Only Sensible Answer

Pipeline tie-ins. The joint was welded in the mill, shipped, coated, and trenched. The final connection is made in a ditch, at night, in weather, by a welder who has to make a root pass that will be X-rayed. Stick is the default because portability and wind tolerance beat deposition rate every time. Field crews care less about chasing wire-feed setups and more about a machine that starts reliably at 40°F.

Ship repair at sea. A cracked deck bracket or a failing bulkhead weld can’t wait for a port. The repair happens while the vessel is underway, in salt air, with space limited to a small toolbox and a portable inverter. Electrodes travel in sealed containers, and the operator can choose push or pull depending on access.

Emergency farm equipment repair. A snapped loader arm or a cracked tractor frame doesn’t get hauled to a shop in planting season. Someone drives out with a generator, a ground clamp, and a handful of 6011 or 7018 rods, cleans the crack with a grinder, and welds it in the dirt. Construction crews keep a stick machine on the trailer for exactly the same reason.

Where the Jobs Are

If you’re reading this as a career question, the placement data matters. The U.S. Bureau of Labor Statistics lists welders, cutters, solderers, and brazers among the large production occupations, with employment concentrated in manufacturing and construction. The welding workforce data and AWS career resources both point to the same structural reality: tens of thousands of openings every year, driven by retirements, with roughly 21% of the U.S. welding workforce over the age of 55. AWS workforce data reported by The Fabricator reinforces that pattern.

That demand concentrates exactly where SMAW rules: structural fabrication shops, pipeline contractors, shipyards, energy infrastructure, and heavy maintenance. Field service and repair roles tend to pay a premium precisely because they require a welder who can produce a sound all-position stick weld without a fume extractor, a fixture, or a second person holding the light. Add the safety literacy expected around hot work, and it pays to keep your welding PPE knowledge current alongside your technique.

Benefits, Challenges, and the 8 Most Common MM Welding Mistakes

Every welding process is a trade-off. MM welding gives you more forgiveness in the field than almost anything else, but it also hands you more ways to make a mess. Knowing both sides honestly is what separates a welder who gets called back from one who gets replaced.

Why MM Welding Still Earns Its Keep

• Cheapest way to start. A complete stick setup usually costs less than a decent MIG package, because you skip the gas bottle, regulator, flowmeter, and liner consumables.
• Truly portable. No shielding gas to carry means the whole kit fits in a truck bed and runs off a portable generator. If you can haul the machine, you can weld.
• It thrives where other processes struggle. Stick arcs tolerate wind, light rust, mill scale, and field grime far better than a gas-shielded arc. That is why structural crews, pipeline crews, and ship repair teams still default to it.
• All-position capability. With the right rod, the same machine handles flat, horizontal, vertical, and overhead work, as covered in our guide to overhead stick welding.
• Thick and awkward joints. Deep-penetrating electrodes handle heavy plate, poor fit-up, and even joining dissimilar or coated steels that would stall a wire feeder.
• Low barrier to entry. As our honest beginner’s guide to stick welding explains, the process is simple to understand and hard to master, which makes early progress feel rewarding.

The Honest Challenges

• Slag inclusion and porosity. These remain among the most frequent visual-inspection rejects in manual stick welding. Slag must be chipped and brushed between every pass, no exceptions.
• Spatter and cleanup. Expect grinding and wire-brushing that a tidy MIG weld never requires.
• Fumes. Flux burning produces more airborne fume per pass than most processes, which is exactly why OSHA’s welding fact sheet stresses ventilation and respiratory protection. Your welding PPE is part of that system, not an afterthought.
• Slower deposition than MIG. Each electrode stops when it burns to a stub, so joints take longer.
• Rod waste. The leftover stub, often around an inch, is money thrown in the scrap bucket on every electrode.
• Restarts take skill. Craters, cold laps, and lack of fusion cluster around stop-start points.
• Moisture sensitivity. Basic-coated E7018 absorbs moisture quickly. AWS A5.1 permits only limited atmospheric exposure before hydrogen-induced cracking risk climbs, which is why low-hydrogen rods belong in a rod oven or sealed container.

The 8 Most Common MM Welding Mistakes and Their Fixes

1. Wrong amperage. Too cold gives a high-crowned bead with cold lap; too hot causes burn-through and violent spatter. Always start from the electrode maker’s recommended range and fine-tune by puddle behavior. Our 5/32 E7018 amperage guide shows the method for a common rod size.
2. Arc length too long. Keep it roughly equal to the core wire diameter. A long arc wanders, loses shielding, and invites porosity and undercut, two defects that fail inspection immediately.
3. Wrong rod for the material. A fast-freeze 6010 on a heavy cap pass, or a soft 7018 on dirty plate, both fight the job. Match electrode type, thickness, and polarity before you strike an arc.
4. Skipping preheat. Thicker carbon-steel sections and steels with higher carbon equivalents commonly require preheat to prevent cold cracking. Check the WPS or calculate the carbon equivalent instead of guessing.
5. Not cleaning between passes. Slag trapped under the next bead becomes a permanent internal defect. Chip, grind, and wire-brush until the surface is bright.
6. Wrong work and travel angle. For flat and horizontal fillets, a steady 10–15° drag angle is typical. If your beads keep wandering, revisit push or pull technique.
7. Rushing travel speed. Speed must match deposition rate. Move too fast and you get a thin, underfilled bead with poor fusion; too slow and you pile up a lumpy crown.
8. Ignoring interpass temperature. On heavy work, stacking hot beads on already-hot steel over-refines the heat-affected zone. Let the joint cool to the specified interpass range before the next pass.

Fix those eight habits and most “bad weld” problems disappear. The arc itself is rarely the problem; the settings and the hands holding the stinger are.

MM vs MIG vs TIG: Which Welding Process Should You Use?

Every welding forum eventually ends up in the same argument: stick versus MIG versus TIG. The honest answer is that none of them is “best” — each one wins in a different situation. The trick is knowing which job you actually have in front of you before you buy a machine.

Head-to-Head Comparison

Why Stick Still Wins the Field

Stick welding typically has the lowest equipment and consumable cost entry point, and it is the only one of the three fully practical without a gas cylinder in the field. No bottle to drag up a hillside, no regulator to freeze, no gas to lose in the wind. That is why structural crews, pipeline tie-ins, and farm repairs still run stick rods. The trade-off is rod waste: every leftover stub is scrap, and you stop to change electrodes every few inches. If rod selection is your weak spot, our electrode buying guide breaks down E6010 through E7018 by material and position.

Why MIG Owns the Shop Floor

MIG (GMAW) uses a continuous solid wire electrode fed from a spool, which eliminates rod changes and stub waste found in stick welding. Once the settings are dialed in, a beginner can lay a decent bead in an afternoon, and the deposition rate keeps production moving. The catch: that solid wire needs shielding gas, so wind blows your weld quality apart, and you are tied to a cylinder. Setting one up correctly is easier than it looks — walk through it in our MIG welder setup guide.

Why TIG Is the Precision Tool

TIG (GTAW) gives the highest control and cleanest bead but is the slowest and most skill-intensive process. You are coordinating a foot pedal or torch amperage, a filler rod, and a tight arc all at once. When it goes right, the result is show-quality and requires almost no cleanup. When you need that control on thin material, see our TIG sheet metal guide.

Two Honourable Mentions

Flux-cored arc welding (FCAW) is essentially MIG’s gas-free cousin: tubular wire filled with flux, so it tolerates wind and dirty metal like stick does while keeping the continuous-wire speed advantage. It produces more smoke and spatter, which is why ventilation matters — review the basics in flux core wire tips. Oxy-fuel isn’t an arc process at all; it cuts, brazes, and heats, and every fabrication shop still keeps a torch set for demolition and bending.

Clear Decision Rules

• Choose stick for outdoor work, heavy or rusty/thick material, pipe and structural code work, and field repair.
• Choose MIG for thin sheet, speed, repetition, and production fabrication.
• Choose TIG for precision, cosmetics, stainless, and aluminum.

Most real shops keep all three — plus combo machines that cover two processes in one box. And whichever process you run, the protection rules stay the same: proper welding PPE is non-negotiable across all three.

Safety, Fumes, and Certification: Protecting Yourself and Passing Inspection

Stick welding hands you something MIG and TIG rarely do: a front-row seat to molten metal, burning flux, and a cloud of fumes you can smell. That intimacy is why MM welding is so learnable, and also why it is the process most likely to hurt someone who never read a single safety sheet. This section is the one you should bookmark, because the habits here decide whether you weld for thirty years or thirty months.

What You Are Actually Breathing

Every stick electrode produces smoke. The flux coating that shields the puddle also breaks down into gases and particulates, and whatever is on the base plate gets vaporized too. Paint, primer, galvanizing, oil, and rust all contribute. The most dangerous coating on steel is any chromium-bearing primer or stainless steel itself, because welding it can release hexavalent chromium, Cr(VI). OSHA regulates this directly, and its Permissible Exposure Limit is 5 µg/m³ as an 8-hour time-weighted average, with additional short-term and action-level requirements spelled out in OSHA’s exposure controls guidance. NIOSH has published its own updated recommended exposure limit for Cr(VI) in NIOSH Publication 2013-128, and it is worth reading if you work around stainless regularly.

Ventilation, Respirators, and Hot Work Rules

The hierarchy is simple. First, work outdoors or in a well-drafty shop. Second, use local exhaust ventilation at the point of the arc. Third, if you cannot control the exposure, wear respiratory protection selected and fit-tested for the contaminant. A dust mask is not a fume respirator, and a respirator is not a substitute for ventilation. OSHA Fact Sheet 3647 lays this out in plain language for welders and shop owners.

The rest of the hazard list is older than any regulation:

• Fire. Hot slag lands on dry wood, cardboard, paper rags, and paint chips, and it stays hot for minutes. Clear a 35-foot radius where practical, cover combustibles, and keep a charged extinguisher within arm’s reach. For any hot work permit situation, plan a fire watch of at least 30 to 60 minutes after you finish, because slag can smoulder unseen.
• Arc radiation. The arc burns retinas. Your helmet shade should track the amperage, roughly starting around shade 8 or 9 and climbing into the 12 to 14 range for heavy current on thick plate. Under-hood, wear safety glasses. Over-the-lens flashes are how welders end up with arc burn at 2 a.m.
• Electrical. Stick welding runs at dangerous voltages open-circuit on DC machines. Insulate yourself from ground, keep cables dry and undamaged, and inspect your connectors. Poor connections are the most underrated failure in a stick setup; our guide to welding connectors shows what to check.
• Confined spaces. Tanks, pits, and hull sections accumulate fumes that do not ventilate themselves, and they displace oxygen. Never weld in one without atmospheric testing, forced ventilation, and an attendant outside.

For the full gear breakdown, see our complete guide to welding PPE, and note that the same principles apply across processes; our MIG welding safety guide covers the same fire and ventilation fundamentals with different shielding-gas concerns.

Certification: The Difference Between a Welder and a Guy Who Welds

Here is the part nobody tells beginners. Passing a fillet or groove weld visually is not certification. In code work, you become qualified through a Welder Performance Qualification (WPQ) test: you weld a test coupon in a specific process, position, and joint, and it gets inspected and often radiographed. The AWS Certified Welder program records those qualifications against codes such as AWS D1.1 for structural steel, and the card you carry is essentially a portable résumé. Our pipe welding procedures guide walks through WPS, positions, and inspection in more detail.

Visual inspection itself is not complicated: look for undercut along the toes, porosity, lack of fusion at the root, and bead profile. Undercut has defined acceptance limits by leg length, which our undercut defects guide explains properly.

The payoff is measurable. The Bureau of Labor Statistics shows steady demand for welders, with employment concentrated in manufacturing and construction, and wage data compiled at Welding Workforce Data consistently shows certified, multi-position welders out-earning uncertified peers. Certification does not make your welds better. It makes them provable, and in inspection-driven work, provable is what gets hired.

Practical Tips, Practice Drills, and Conclusion: Getting Good at MM Welding

Knowing the numbers is half the battle. The other half is muscle memory, and muscle memory only comes from burning rods on purpose instead of guessing. Here is the closing playbook I give every beginner who walks into the shop.

A 30-Day Practice Plan That Actually Works

Four weeks, one hour a day, one machine. The progression matters more than the total time.

• Days 1–7: Flat bead-on-plate. Run straight stringers on 6 mm plate in the flat position. The two skills you are building here are a consistent arc length and a steady travel speed, and they transfer to every position you will ever weld. If you cannot lay a straight, evenly rippled bead flat, nothing else will work yet. Start on a forgiving rod like 6013, then switch to low-hydrogen rods using the settings in our 3/32 E7018 amperage guide.
• Days 8–14: Fillet welds, 1F then 2F. T-joints in the flat position first, then horizontal. Focus on tying into both toes evenly, not on stacking pretty ripples.
• Days 15–21: 3F vertical and 4F overhead. Vertical-up with a small weave, then overhead with a tight arc and a 3/32 rod. Overhead stick welding is where beginners discover whether their arc length discipline is real.
• Days 22–30: Groove joints. Single-V butt welds in 6 mm plate, root pass, hot pass, cap. Practice cleaning between every pass. This is also the week to work on restarts, since most real-world defects show up where a rod was struck again.

How to Self-Inspect Your Welds

You do not need a lab to judge your own work. Check five things, in this order:

1. Fusion: Did the weld wet into the base metal, or is it sitting on top like a caterpillar? Lack of fusion is the defect that quietly fails in service.
2. Undercut: Look for grooves melted into the base metal beside the toe. Acceptance limits depend on thickness and code, so compare your bead against the visual inspection criteria in AWS D1.1 rather than eyeballing it.
3. Porosity: Pinholes mean contamination, a long arc, or a damp electrode. One or two isolated pores may be acceptable under a code; clustered pores are not.
4. Bead profile: A high, crowned bead usually means you ran too cold or too slow. A flat, washed-out bead means too hot or too fast.
5. Reinforcement: Excess crown beyond the code limit is not stronger, it is just extra grinding. Our undercut defect guide covers causes, limits, and repair in detail.

Reworking a Bad Weld

Most bad stick welds are reworkable. Chip the slag, wire-brush, and grind the defect out completely with a burr or a cutting wheel until you see bright, sound metal. Undercut gets filled with a small controlled pass; porosity gets ground out and rewelded. Never cap over a defect and hope. If the crack or lack of fusion runs deep into the joint, gouge it back to sound metal and start the pass again.

Know when to stop. Structural members, pressure-retaining parts, gas lines, and anything load-bearing overhead should be handled by a code-qualified welder working to a written procedure.

The Checklist Worth Taping to Your Machine

• Pick the right rod for the material and the position.
• Set the amperage from the electrode manufacturer’s range, not from feel.
• Keep arc length equal to the core wire diameter.
• Clean and de-slag between every pass.
• Ventilate the space and wear proper PPE.
• Get certified when you are ready to get paid for it.

That last line is worth more than any setting chart. The Bureau of Labor Statistics and industry workforce data show roughly 82,500–90,000 welding openings projected annually in coming years, and the candidates who get picked are almost always the ones holding a code qualification to AWS D1.1 or equivalent. Certification does not make you a better welder overnight, but it proves it to an employer. If safety and gear are still fuzzy, our welding PPE guide is the right next read.

Back to That Gate

Remember the fabricator who lost a ₹40,000 job when a vertical seam cracked three days after installation? The fix was never complicated. He would have looked up the electrode’s recommended amperage range instead of dialing by feel, kept a tight arc on that 3F joint, cleaned between passes, and run a quick visual check against the acceptance criteria before the gate left the shop. Same rod, same machine, same hour of the day. The only difference was a few minutes of discipline. That is the whole secret of MM welding: the process is cheap, portable, and forgiving of the environment, but it demands precision from you. Learn the numbers, burn the rods, inspect your own work, and get certified. The jobs are there, and they go to the welder who checked.

Frequently Asked Questions

What does MM welding mean?

MM welding means Manual Metal Arc welding (often written MMA/MMAW), the technical name for shielded metal arc welding (SMAW), commonly called stick welding. It uses a flux-coated consumable electrode that creates both the arc and the shielding gas.

What is the difference between MM welding and stick welding?

There is no difference — they are the same process. ‘MM’ or ‘MMA’ is the formal trade/engineering name, ‘SMAW’ is the AWS designation, and ‘stick welding’ is the shop-floor nickname for the same arc welding method.

Which electrode should a beginner start with?

Start with an E6013 rod — it runs well on AC or DC, strikes easily, produces a smooth bead, and forgives slight arc-length mistakes. Move to E7018 for structural strength and E6010/E6011 for root passes and out-of-position work.

What amp setting should I use for MM welding?

A common baseline is about 1 amp per 0.001 inch of electrode diameter — for example, a 3.2 mm (1/8 in.) rod starts around 110–125 amps on flat mild steel. Adjust down for thin material or vertical/overhead positions and up for thick plate.

Can MM welding be used outdoors or on rusty metal?

Yes — this is stick welding’s biggest advantage. Because the flux coating generates its own shielding gas, wind has little effect, and the arc can burn through light rust, paint, and mill scale better than gas-shielded MIG welding.

How do I calculate the size of a fillet weld in mm?

A fillet weld is specified by its leg size, and the effective throat equals 0.707 times the leg for a 45° fillet. A 6 mm leg therefore gives roughly a 4.24 mm throat, which is the dimension used in strength calculations.

What are the biggest safety risks of MM welding?

The main risks are welding fumes (including hexavalent chromium when welding stainless steel), arc radiation to the eyes and skin, electric shock, and fire. OSHA limits Cr(VI) to 5 µg/m³ over an 8-hour TWA and requires ventilation, respiratory protection, and fire precautions.

Do I need certification to work as a stick welder?

Formal certification is not legally required for all jobs, but most structural, pipeline, and pressure-work employers require a welder performance qualification test to a code such as AWS D1.1. Certification significantly improves job prospects and pay.

Is MM welding harder to learn than MIG welding?

Stick welding has a steeper initial learning curve because you control rod angle, arc length, and travel speed manually while the electrode burns down. Most learners produce usable welds within a few practice sessions and become competent within a few months of regular practice.

Why is my stick weld covered in slag and cracking?

Cracks and trapped slag usually come from too-low amperage, an arc length that is too long, or skipping cleaning between passes. Bump up the heat slightly, keep the arc tight, and chip and brush each pass before laying the next one.