Manual Metal Arc Welding (MMAW): The Complete Guide

It is 7 a.m. on a muddy pipeline right-of-way, the wind is gusting, and the only machine on site is a battered engine-driven welder with a stinger hanging off it. Nobody is reaching for a MIG gun in that weather, because manual metal arc welding is the process that still gets the job done when conditions are ugly. But most beginners who pick up a stinger discover within ten minutes that the rod sticks, the slag hides the weld, and the machine settings they copied from a video do not match their steel.

What Is Manual Metal Arc Welding (MMAW)? Straight Answers First

Gusting wind, a muddy right-of-way, one battered engine-driven machine, and a stinger lying in the dirt. That picture explains why this process refuses to die. But before the romance of field work, let’s answer the plain question.

Manual metal arc welding (MMAW) is a manual arc welding process that joins metal with an electric arc struck between a consumable, flux-coated electrode and the workpiece. The welder holds the electrode in a holder and feeds it into the arc by hand, controlling arc length, travel angle, and speed through nothing but eye, ear, and wrist. The coating on the rod is not decoration. As the arc burns, that covering decomposes to generate the shielding gas that protects the molten metal, and it leaves behind a slag layer that blankets the cooling weld.

The Names, the Number, and the Official Definition

You will see three labels for the same process, and they are interchangeable in practice. In Europe and much of the ISO world it is MMAW. In North American code work it is shielded metal arc welding (SMAW). On a job site, almost everyone just says stick welding, because the electrode looks like a short stick.

The process carries a formal identity: ISO 4063 process number 111, which places it in the international numbering system for welding and allied processes. You can see the classification laid out in the standard description of shielded metal arc welding. AWS frames it in similar mechanical terms, defining SMAW as an arc welding process that produces coalescence with an electric arc between a covered metal electrode and the work. Details are in the AWS Welding Handbook materials.

The Basic Circuit: Six Components and an Arc

Strip away the jargon and MMAW is a simple loop of current with a controlled gap in it. Follow the path from the machine to the metal:

• Power source: a constant-current welding machine, transformer, inverter, or engine-driven generator, supplying roughly 20 to 35 volts at the arc.
• Work lead and ground clamp: the return path, clamped to clean bare metal on the workpiece.
• Electrode holder (stinger): insulated, spring-loaded, and rated for the current it carries.
• Consumable electrode: a steel core wrapped in flux coating, sized by diameter and classified by code.
• Workpiece: the base metal being joined, which becomes part of the circuit.
• The arc: the visible plasma bridge where electrical energy becomes heat.

That is the whole system. No gas cylinder, no wire feeder, no foot pedal. This simplicity is exactly why the process travels well.

How MMAW Fits Beside MIG and TIG

MIG welding feeds a bare wire continuously and relies on a separate shielding gas bottle. TIG welding uses a non-consumable tungsten electrode and a gas shield, with filler added separately by hand. MMAW is the odd one out: the electrode is both filler metal and shielding system, and it is consumed as you weld. One hand steadies the stinger, the other chips slag later. That single self-contained rod is the source of both its toughness and its slowness.

Why It Still Runs the Field

Portability, wind tolerance, low equipment cost, and the ability to weld steel that is less than spotless keep MMAW in demand. Because shielding gas is generated at the arc rather than blown in from a cylinder, breeze disrupts it far less than it disrupts MIG or TIG. That is not a small advantage outdoors. Add a machine that runs off a generator, rods that survive in a truck bed, and the ability to burn through light rust and mill scale, and you have the default process for maintenance, repair, pipeline, and remote construction. The trade-off is honest: deposition is slow. Industry estimates put the operator factor for SMAW at roughly 25 percent, meaning only about a quarter of paid time goes into actually laying weld, with electrode changes and slag removal eating the rest, as outlined in this WTIA process overview.

What This Guide Covers

Knowing the definition is not the same as running a bead. The sections ahead move from how the arc physically behaves, through decoding electrode codes and setting up a machine, into technique, metallurgy, defects, safety compliance, and honest comparisons with MIG, TIG, and flux-cored welding. If you want the short version of why the process endures, the advantages of stick welding are worth reviewing before you continue. Otherwise, start with the physics, because everything else follows from it.

How MMAW Actually Works: Arc, Droplets, Gas, and Slag

Stick welding looks simple from a distance: clamp a ground, strike an arc, drag the rod. Up close it is a small controlled storm of electricity, melted metal, gas, and glass. Understanding that storm is what separates a welder who guesses from one who can diagnose a bad bead and fix it.

Striking and Holding the Arc

With no arc burning, the machine sits at open-circuit voltage (OCV), commonly somewhere around 50 to 80 volts. Touch the electrode to the work and current flows through a tiny contact point that heats and vaporizes almost instantly. Pull back slightly and the arc establishes itself; once it is running, voltage drops to roughly 20 to 35 volts. That drop is deliberate. The power source is a constant current, or drooping, design, so voltage sags as the arc lengthens while current stays roughly steady. Hold a long arc and voltage climbs; shorten it and voltage falls. The electrode tip and the base metal both melt within a fraction of a second.

Steel melts at about 1,370 to 1,540 °C (2,500 to 2,800 °F), and the arc column is far hotter, which is why the puddle forms almost before you are ready for it. The heat does two jobs at once: it melts a shallow pool into the base plate and melts the electrode tip into a droplet. Electromagnetic force, gravity, and the gas jet push that droplet across the gap. Some electrodes transfer in a fine spray, others in larger globules, and that difference explains a lot about how smooth or violent a rod feels in your hand.

What the Flux Coating Is Doing

The bare wire core is only half the electrode. The covering is a carefully engineered mineral mix doing several jobs at the same time, as described in the standard process description of shielded metal arc welding:

• Shielding gas: the coating burns and decomposes to blanket the arc and puddle, keeping nitrogen and oxygen out. Both mean porosity and brittle, dirty steel.
• Slag: molten minerals float to the surface and freeze into a glassy or crusty layer that keeps protecting the metal as it cools.
• Arc stabilization: potassium and sodium compounds help the arc start and stay steady, particularly on AC.
• Deoxidation and alloying: silicon, manganese, and other elements scavenge oxygen and can add alloy to the deposit.

Because slag freezes over the bead, you cannot see your weld until you chip it off, which is also why you must remove it between passes. Trapped slag becomes a slag inclusion, one of the most common discontinuities in stick welding and a classic cause of failed bend tests.

Coating Families in Plain Language

Cellulosic coatings burn with a forceful gas shield and produce deep, fierce penetration, which is why they dominate pipeline root passes. Rutile coatings give a soft, easy arc, smooth beads, and a slag that often lifts off by itself, making them a favourite for general work and thinner material. Basic (low-hydrogen) coatings keep hydrogen out of the weld for toughness and crack resistance on structural steel, at the cost of fussier storage and a less forgiving arc. Iron-powder coatings add metal powder to the covering for a much higher deposition rate, but they generally want flat or horizontal work.

Fast-Fill, Fast-Freeze, and Fill-Freeze

Electrodes are also sorted by how the slag behaves, which is often more useful on the job than chemistry. Fast-freeze electrodes solidify quickly, so the puddle stays put in vertical and overhead work. Fast-fill rods put down a lot of metal fast and suit flat and horizontal positions where the puddle can spread. Fill-freeze sits between the two, freezing at a moderate rate. The all position welding rod guide is a useful next stop if you are choosing between them for out-of-position work.

Penetration, Dilution, and Heat Input

Penetration profile is the shape of the melted zone under the bead: shallow and wide, deep and finger-like, or something in between, depending on current, polarity, arc length, and coating type. Dilution is how much base metal mixes into the deposit, which matters on alloy steels because it drags the parent chemistry into your filler. Heat input combines amps, volts, and travel speed into one number describing the energy going into each millimetre of weld. Travel slower and heat input rises, bringing more distortion and a wider heat-affected zone.

AC vs DC Arc Behaviour

On direct current the arc burns steadily in one direction, and polarity decides where the heat lands. DC electrode positive puts more heat into the work for deeper penetration; electrode negative reverses that. Alternating current crosses zero twice per cycle, so the arc extinguishes and restarts constantly. Good stabilizers in the coating keep it lit, but AC generally feels softer and penetrates less, trading that for fewer magnetic headaches and cheaper machines.

None of this is abstract. Every setting you turn and every technique you use nudges one of these variables, which is exactly where the practical advantages of stick welding come from.

Reading Electrode Codes: What E7018, E6013, and E6010 Really Mean

An electrode carton can look like a code you need a badge to read. It isn’t. Once you know the pattern, a number like E7018 tells you the deposit strength, the positions it can weld, the coating type, and the current it expects.

Decoding the AWS A5.1 Number

Carbon steel covered electrodes are classified under AWS A5.1. The system is deliberately logical. E means electrode. The next two digits give minimum tensile strength in thousands of pounds per square inch (ksi). The third digit gives position: 1 is all-position, 2 is flat and horizontal only. The fourth digit describes the coating and current.

So E7018 means electrode, 70,000 psi minimum tensile strength, all-position, and a low-hydrogen iron-powder coating that runs on AC or DCEP. That is the full story in five characters.

A suffix adds detail. -1 usually signals improved impact toughness, while H4R indicates a maximum of 4 mL of diffusible hydrogen per 100 g of deposit and a moisture-resistant coating. Treat these as clues, not a substitute for the manufacturer’s data sheet, which controls amperage range, polarity, re-drying, and storage.

The Five Workhorse Electrodes

E6010 is a cellulosic-coated electrode for direct current electrode positive (DCEP). It gives deep penetration and a fast-freezing slag, which is why it remains a standard choice for pipeline root passes and difficult fit-ups. E6011 is its AC-capable cousin: similar cellulosic behavior, less dependence on a DC machine.

E6013 is the friendly general-purpose rod. Its rutile coating starts easily, runs smoothly at low current, and leaves a slag that often lifts off by itself. It suits sheet metal, light fabrication, and hobby work, but it is not a deep-penetration electrode. E7018 is the structural workhorse: low hydrogen, all-position, smooth-running, and common on bridges, buildings, and pressure work. E7024 is an iron-powder electrode built for flat and horizontal positions only. It lays down a lot of metal quickly, but do not expect it to perform overhead.

Electrode	Strength	Positions	Current	Best use
E6010	60,000 psi	All	DCEP	Pipeline roots, deep penetration
E6011	60,000 psi	All	AC or DCEP	General repair, AC machines
E6013	60,000 psi	All	AC or DCEP	Sheet metal, light fabrication
E7018	70,000 psi	All	AC or DCEP	Structural steel, low hydrogen
E7024	70,000 psi	Flat, horizontal	AC or DCEP	High deposition, flat work

Low-Hydrogen Storage: The Rule Beginners Break

E7018 and other low-hydrogen electrodes absorb moisture from the air. A damp coating can put hydrogen into the weld, and hydrogen is linked to cracking in restrained or high-strength joints. Good practice means holding ovens on site, sealed containers until the rod is used, and re-drying according to the manufacturer’s schedule.

No universal exposure clock fits every job. The applicable welding code, procedure, and manufacturer instructions set the limit, and many procedures measure it in hours rather than days. If a rod has sat open in humid air, do not assume it is fine because the coating looks dry.

Stainless, Cast Iron, Hardfacing, and Aluminum

Stainless covered electrodes sit under AWS A5.4. E308L-16 suits 304L-type stainless, while E316L-16 adds molybdenum for 316L and similar grades. The “-16” indicates a rutile coating designed for AC or DCEP. Alloy steel classifications move to AWS A5.5, so check the exact grade rather than assuming a carbon steel rod will do; our guide to alloy steel welding electrodes explains the selection issues.

Cast iron repair commonly uses nickel-based electrodes classified under AWS A5.15. They deposit a softer, more machinable weld and reduce cracking risk compared with steel electrodes, though preheat and technique still matter. Hardfacing uses its own family of build-up and wear-resistant electrodes. Aluminum stick electrodes exist, but they are uncommon and awkward compared with wire processes. For most aluminum work, TIG or MIG is the practical route, as covered in our aluminum MIG welding guide.

Choosing Diameter Without Guessing

Stick electrodes run from about 1.6 mm (1/16 in) to 6.0 mm (1/4 in). Small rods suit thin material and low current, where a large rod would burn through. A 2.4 mm (3/32 in) rod is a versatile general-purpose size and a common root-pass choice. A 3.2 mm (1/8 in) rod handles most repair and fabrication work, while 4.0 mm and larger rods are for thicker plate and higher deposition.

Diameter and amperage rise together, but the manufacturer’s range is the authority. A rod that runs well at 110 A in one brand may want 125 A in another. Match the rod to plate thickness and joint design, then tune within the published range. For position work, our all-position welding rod guide goes deeper into technique and selection.

Read the label first, confirm the data sheet second, and only then reach for the stinger. The code is there to save you from guessing.

Machine Setup: Polarity, Amperage, Duty Cycle, and Cables

Most stick welding problems that look like bad technique are actually setup problems. The rod sticks, the arc sputters, the bead sits tall and cold, and the operator starts blaming their hands. Four things need to be right before you strike an arc: the machine’s output characteristics, the polarity, the amperage, and the path the current takes from the machine to the work.

Constant Current Machines and the Drooping Curve

Stick welding runs on constant-current (CC) power sources with a steeply drooping volt-ampere curve. In practice, current stays relatively stable as arc length changes while voltage swings widely. That matters because your hand is the wire feeder. Drift a little too close and the voltage collapses while the current barely moves, so you don’t instantly blow a hole through the plate. Stretch the arc and the machine keeps pushing roughly the same amps, letting the arc recover instead of extinguishing.

Wire-feed processes like MIG use constant-voltage (CV) machines, where voltage is held and current varies with wire feed speed. Confusing the two is common, and you cannot set a stick machine like a MIG machine and expect the same behavior. The AWS Welding Handbook covers these power source characteristics in detail if you want the engineering behind the droop.

Polarity: DCEP, DCEN, and AC

Polarity decides where the heat concentrates. With direct current electrode positive (DCEP), roughly two-thirds of the arc heat lands in the electrode, melting the tip fast, giving deeper penetration, and producing the most stable arc for cellulosic rods. Direct current electrode negative (DCEN) shifts more heat into the workpiece for shallower penetration and higher deposition efficiency, which suits thinner material and some specialty electrodes. Alternating current splits the difference and helps when arc blow is fighting you.

Electrode choice drives the decision, not preference. E6010 requires DCEP. E6013 runs on AC or either DC polarity, and E7018 runs on AC or DCEP. Get it backwards and the rod stubs out, sputters, or refuses to hold an arc. If you’re still sorting out which rod suits which position, the all position welding rod guide pairs well with this section.

Setting Amperage (and Tuning by Ear)

A widely used rule of thumb sets amperage at roughly 1 amp per 0.001 inch of electrode diameter, putting a 3/32 in (2.4 mm) rod near 90 to 95 A and a 1/8 in (3.2 mm) rod near 125 A as starting points. Tune from there by sound and behavior rather than the dial:

• Right: a steady bacon-frying crackle, slag curling at the edges, bead toes wetting into the plate.
• Too hot: loud popping, heavy spatter, a wide flat bead, undercut along the edges, and a rod glowing red too far up.
• Too cold: a hissing arc, a tall ropey bead sitting on top of the plate, poor fusion, frequent sticking.

Duty Cycle in Plain Numbers

Duty cycle is a percentage of a 10-minute period. A 60 percent duty cycle at 200 A allows

Machine Setup: Polarity, Amperage, Duty Cycle, and Cables

Most stick welding problems that look like bad technique are actually setup problems. The rod sticks, the arc sputters, the bead sits tall and cold, and the operator starts blaming their hands. Four things need to be right before you strike an arc: the machine’s output characteristics, the polarity, the amperage, and the path the current takes from the machine to the work.

Constant Current Machines and the Drooping Curve

Stick welding runs on constant-current (CC) power sources with a steeply drooping volt-ampere curve. In practice, current stays relatively stable as arc length changes while voltage swings widely. That matters because your hand is the wire feeder. Drift a little too close and the voltage collapses while the current barely moves, so you don’t instantly blow a hole through the plate. Stretch the arc and the machine keeps pushing roughly the same amps, letting the arc recover instead of extinguishing.

Wire-feed processes like MIG use constant-voltage (CV) machines, where voltage is held and current varies with wire feed speed. Confusing the two is common, and you cannot set a stick machine like a MIG machine and expect the same behavior. The AWS Welding Handbook covers these power source characteristics in detail if you want the engineering behind the droop.

Polarity: DCEP, DCEN, and AC

Polarity decides where the heat concentrates. With direct current electrode positive (DCEP), roughly two-thirds of the arc heat lands in the electrode, melting the tip fast, giving deeper penetration, and producing the most stable arc for cellulosic rods. Direct current electrode negative (DCEN) shifts more heat into the workpiece for shallower penetration and higher deposition efficiency, which suits thinner material and some specialty electrodes. Alternating current splits the difference and helps when arc blow is fighting you.

Electrode choice drives the decision, not preference. E6010 requires DCEP. E6013 runs on AC or either DC polarity, and E7018 runs on AC or DCEP. Get it backwards and the rod stubs out, sputters, or refuses to hold an arc. If you’re still sorting out which rod suits which position, the all position welding rod guide pairs well with this section.

Setting Amperage (and Tuning by Ear)

A widely used rule of thumb sets amperage at roughly 1 amp per 0.001 inch of electrode diameter, putting a 3/32 in (2.4 mm) rod near 90 to 95 A and a 1/8 in (3.2 mm) rod near 125 A as starting points. Tune from there by sound and behavior rather than the dial:

• Right: a steady bacon-frying crackle, slag curling at the edges, bead toes wetting into the plate.
• Too hot: loud popping, heavy spatter, a wide flat bead, undercut along the edges, and a rod glowing red too far up.
• Too cold: a hissing arc, a tall ropey bead sitting on top of the plate, poor fusion, frequent sticking.

Duty Cycle in Plain Numbers

Duty cycle is a percentage of a 10-minute period. A 60 percent duty cycle at 200 A allows 6 minutes of actual arc time followed by 4 minutes of cooling. It is not 60 percent of an hour, and it is not a suggestion. Push past the rated time at that amperage and thermal protection cuts output until the internals cool, usually right in the middle of your best bead. Duty cycle also rises as amperage drops, so a machine rated 60 percent at 200 A may run continuously at 150 A. Read the data plate rather than assuming.

Cables, Ground Clamps, and Voltage Drop

Poor work lead connections and undersized cables cause voltage drop, which shows up as a weak, unstable arc you cannot fix with the amperage dial. Clamp the ground to clean, bare metal on the workpiece itself or as close as possible. Never clamp to paint, rust, grease, or a welding table your part is merely resting on. Keep leads short and straight, skip coiling them around your arm, and inspect the stinger for cracked insulation and a loose jaw. Size the cable for the amperage and length you’re running, and if you must feed the machine through an extension cord, keep it short and heavy-gauge.

Pre-Arc Startup Checklist

1. Confirm the machine is set to the correct process and polarity for your electrode.
2. Set amperage from rod diameter and material thickness, then fine-tune after the first bead.
3. Note the duty cycle rating at your chosen amperage and plan your work-to-rest rhythm.
4. Clean the ground contact to bare metal and clamp close to the joint.
5. Inspect stinger insulation, cable jacket, and ground clamp condition.
6. Verify the electrode is dry, undamaged, and the right classification for the job.
7. Confirm ventilation and fire watch arrangements before the first arc.

Once those boxes are ticked, the machine stops being the variable. What remains is arc control, which is exactly where the next section picks up.

Technique That Works: Striking, Travel Angle, Arc Length, and Restarts

Good manual metal arc welding looks calm because the operator is reading the arc, not fighting it. The rod, the sound, the slag line, and the shape of the pool all give feedback. Learn what those signals mean and your beads become consistent instead of accidental.

Starting the Arc Without Welding the Rod to the Plate

There are two reliable starts. The scratch start strikes the electrode like a match, flicking it across the surface before lifting to arc length. The tap start touches the rod down and lifts it straight up in one quick motion. Scratch starts suit most general work; tap starts are cleaner once you can control the lift.

Sticking usually comes from low amperage, a damp or damaged flux coating, dirty metal, or hesitating after contact. If the rod sticks, release the stinger immediately, twist the rod free, clean the tip, and check your settings before trying again. Never pull a live electrode away while your other hand is near the work.

Arc Length: Listen for Bacon, Not Numbers

Arc length is the gap between the electrode tip and the molten pool. Most electrodes run best with a short arc, roughly one rod diameter or less. Cellulosic rods need a tight arc, while low-hydrogen rods are often dragged with the flux nearly touching the plate. Too long an arc raises voltage, widens the arc cone, throws more spatter, and reduces penetration. Too short an arc causes sticking and a lumpy, inconsistent bead.

Your ears are a better gauge than the number on the machine. A steady bacon-frying sound means the arc is stable. A sharp popping hiss usually means the arc is too long. Silence, or a buzzing struggle, means the rod is stuck or the circuit is poor. The process fundamentals are simple, but the sound takes practice to trust.

Angles, Speed, and Reading the Pool

Use a travel angle of roughly 10 to 15 degrees. A slight drag angle improves penetration and slag control with many electrodes. A slight push can flatten the bead and improve visibility with rutile rods, but follow the electrode maker and the procedure. Work angle matters just as much: in a fillet, keep about 45 degrees to both plates; on a butt joint, keep the rod perpendicular to the surface unless the position calls for a correction.

Travel speed should keep the arc at the leading edge of the pool. Move too fast and the bead narrows, crowns, and may lack fusion. Move too slowly and the pool widens, overheats, and traps slag. Watch the slag line behind the arc. It should follow smoothly, not race ahead or pile up.

Position by Position

Position	Technique	Watch For
Flat	Slight drag, steady travel, narrow weave if needed	Excess current and a convex bead
Horizontal	45-degree work angle, slight upward tilt, controlled speed	Slag sag and undercut on the upper toe
Vertical up	Slight weave, pause at the toes, move quickly across the center	Overheating and slag traps at the edges
Vertical down	Fast travel, tight arc, thin material and some pipe roots	Lack of penetration on thick steel
Overhead	Lower amperage, short arc, small pool, firm stance	F	Falling slag and burn-through risk

For position work, our all-position welding rod guide helps match electrode class to access and travel direction.

Restarts, Tie-Ins, and Crater Control

Slag must be fully removed and the crater cleaned before a restart. Otherwise the tie-in can trap slag or lack fusion. Strike slightly ahead of the old crater, establish the arc, then move back into the crater and continue. Backstepping, where each new bead starts behind the previous one and overlaps forward, spreads heat and improves tie-ins on multi-pass work. A crater left unfilled is a common cracking site, so pause at the end, add metal to fill it, then break the arc.

Weave Width and the Overheating Trap

Keep weaves narrow, generally no more than about two to three times the electrode diameter unless a procedure says otherwise. Wide weaving overheats the base metal, creates a broad shallow pool, and makes slag traps more likely along the edges. A stepped weave with a brief pause at each toe is safer than a fast, wide swing.

A Beginner Practice Sequence

1. Bead pad: Run overlapping beads on flat plate. Aim for consistent width, height, and spacing, with slag that peels rather than fights.
2. T-joint: Build a 45-degree fillet with equal legs. Check for undercut, slag inclusions, and a smooth toe line.
3. Vertical up: Use a slight weave and pause at the toes. Success means no sagging pool, no slag traps, and a tie-in that survives a bend test.

That control is exactly why stick welding still wins in maintenance and field work, where conditions rarely cooperate.

Metals, Joint Preparation, and Where MMAW Earns Its Keep

Stick welding is not a universal process, and pretending otherwise gets people into trouble. It has a wide but specific comfort zone, and knowing that zone — plus the preparation each metal demands — separates the welder who fights the arc all day from the one who finishes clean.

What MMAW Welds Well

Carbon steel is home turf. SMAW is practical from roughly 1/8 inch (3 mm) and thicker, and it stays comfortable right up through thick plate. Thin sheet is possible with small electrodes and low amperage, but distortion and burn-through risk climb fast, which is why most people reach for MIG below that threshold.

Beyond flat plate, the process handles structural steel, pipe, angle, channel, and general repair. Field pipelines, plant maintenance, farm gates, trailer frames, and broken brackets are classic stick jobs: the equipment travels easily and the arc tolerates imperfect surfaces.

Joint Types and Preparation

The five basic joints — butt, lap, T, corner, and edge — all appear in stick work, but the

The five basic joints — butt, lap, T, corner, and edge — all appear in stick work, but the butt joint deserves the most attention because it demands the most preparation.

• Bevel angle: typically 30 degrees per side on a 60-degree included V-groove for plate thick enough to need one.
• Root gap: sized so the root pass penetrates fully without falling through.
• Land: a small flat at the root face that controls burn-through.
• Fit-up and tacks: tack both sides where possible, then check square and gap before you commit.
• Cleaning: grind, wire brush, or scrape to bare metal. Mill scale, oil, and moisture all feed defects.

Poor fit-up is the quiet killer. A gap that wanders from 2 mm to 6 mm across one joint forces you to change travel speed and current mid-weld, and that inconsistency reappears later as lack of fusion or a lumpy cap.

Preheat and Interpass Temperature

Preheat slows the cooling rate in thicker or higher-carbon steel, reducing hardness and cracking risk in the heat-affected zone. In plain terms, you warm the joint before striking an arc so the weld and surrounding metal cool together more gently. Interpass temperature is the cap on the other end: let the joint cool between passes if it runs too hot, or hold it warm if the procedure calls for it. Thick sections, high-carbon steels, and alloy steels are where these controls matter most, and where a written procedure should govern rather than guesswork. Electrode selection for those grades is its own topic; this guide to alloy steel welding electrodes covers the classification side.

Stainless, Cast Iron, and Hardfacing

Stainless covered electrodes fall under AWS A5.4, with E308L-16 and E316L-16 among the most common choices for 304 and 316 base metals respectively. Two habits matter: keep heat input lower than on carbon steel, and use a dedicated stainless wire brush so you do not contaminate the surface with carbon steel particles.

Cast iron repair uses nickel-based electrodes covered by AWS A5.15. Nickel deposits stay machinable and tolerate dilution from the cast iron base metal. Preheat is debated and job-dependent: a large, restrained casting often benefits, while a small part may be welded cold with short, peened beads. Peening (light hammering of each bead while hot) relieves contraction stress. Hardfacing follows the same logic with different fillers — build a wear-resistant layer on a carbon steel base rather than making the whole part from tool steel.

Job-to-Electrode Quick Reference

Job	Electrode	Typical Diameter
General fabrication, 3–6 mm steel	E6013	2.5–3.2 mm
Structural steel, low hydrogen required	E7018	3.2–4.0 mm
Pipe root, open gap	E6010 / E6011	2.5–3.2 mm
Thick plate, flat, high deposition	E7024	4.0–5.0 mm
304 / 316 stainless	E308L-16 / E316L-16	2.5–3.2 mm
Cast iron repair	Nickel-based (AWS A5.15)	2.5–3.2 mm

Where MMAW Struggles

Thin sheet metal is the clearest weak spot. Aluminum is technically weldable with stick but impractical in most shops — for aluminum, a dedicated process is the honest answer, as covered in this aluminum MIG welding guide. Reactive metals like titanium are out of scope entirely. High-production fabrication belongs to MIG and FCAW, which deposit faster and need no slag chipping. Hydrogen-sensitive steels demand strict low-hydrogen discipline, and stick only gets you there if the electrodes are stored and handled correctly.

Finally, the old line that stick “burns through rust and paint” is half true and entirely unhelpful. It will arc through light contamination, but the porosity and inclusions that follow are your problem. Galvanized coatings are worse: zinc fume is a real respiratory hazard, so strip the coating from the weld zone and provide ventilation and respiratory protection per OSHA’s welding guidance.

Defects and Troubleshooting: Porosity, Slag Inclusions, Undercut, and Arc Blow

Every stick weld defect is a message. The arc is telling you something about moisture, magnetism, travel speed, or a joint you never cleaned. Learn to read it before you grind it out and start over.

Keep this diagnostic reference next to the machine: what each defect looks like, why it happens, and the fix that actually works.

Porosity

Looks like: small round holes scattered on the bead or exposed after grinding, sometimes clustered along the toes.

Causes: damp or damaged electrodes, oil, paint, rust, or galvanizing on the plate, an excessively long arc, and wind blowing the shielding gas away. Fix: bake or replace rods per the manufacturer’s sheet, grind to bare metal, tighten the arc, and build a windbreak.

Slag Inclusions

Looks like: dark, glassy pockets trapped between passes or along the sidewall, often revealed only by grinding or radiography.

Causes: skipping interpass cleaning, a drag angle that pushes slag ahead of the pool, low amperage that lets slag freeze before it floats out, and a weave wide enough to fold slag into the edges. Fix: chip and brush every pass, hold a consistent electrode angle, and raise current slightly within the rod’s range.

Lack of Fusion and Lack of Penetration

Lack of fusion is a cold lap where the bead sits on base metal without melting into it. Lack of penetration is a root that never reached the bottom of the joint. Both hide under a good-looking cap.

Causes: low amperage, fast travel, wrong root gap or land, an electrode angle pointing away from the joint, and a weave that outruns the puddle. Fix: verify settings against the rod data sheet, slow down, aim at the joint root, and check fit-up before striking.

Undercut

Looks like: a groove melted into the base metal along the toe of the weld, left unfilled.

Causes: too much current, too long an arc, and travel speed or work angle errors that let the arc gouge the sidewall faster than the puddle can fill it. Fix: drop the amps, shorten the arc, pause briefly at the toes, and correct the work angle so the arc splits heat evenly. An all-position welding rod guide helps when the problem only appears on vertical or overhead work.

Spatter

Looks like: BBs fused to the plate around the bead. Some is normal with stick; a lot is a signal.

Causes: current too high, arc too long, damp electrodes, and wrong polarity for the coating. Fix: match polarity to the classification, dry the rods, and tighten the arc. Anti-spatter spray helps cleanup but hides nothing.

Arc Blow

Looks like: the arc wandering, spatter trailing to one side, slag piling up on one toe, and a bead that curves away from the seam. It is worst near the ends of a joint or against heavy steel.

The cause is magnetic force deflecting the arc. Mitigate it by shortening the arc, moving the ground clamp, changing travel direction, or switching to AC output. Good work lead connections matter more than most welders think, and the basics in this advantages of stick welding breakdown explain why simple AC machines stay popular on site.

Cracking

Looks like: a fine line through the bead, a transverse crack across the cap, or a crater crack at the end of a run.

Causes: hydrogen, high restraint, missing preheat, poor interpass control, and abrupt arc breaks. Hydrogen-induced cracking in high-strength steel is exactly why low-hydrogen electrodes and disciplined storage exist; damp E7018 defeats the point of buying it. Fix: use properly stored low-hydrogen rods, preheat and control interpass temperature per procedure, fill craters before breaking the arc, and follow the joint sequence to limit restraint. The AWS welding handbook covers these controls in detail.

Profile Problems and Reading a Bead

Convex, ropey beads with high crowns usually mean slow travel and low current. Concave, dished beads with deep toes mean too much heat and too fast a travel. Both change how stress concentrates at the toe, which is why inspectors care about profile as much as size.

• Ripples: fine, evenly spaced lines mean steady travel and current. Erratic spacing points to an unsteady hand or a fluctuating arc length.
• Toe wetting: a smooth, gently blended edge is healthy. A sharp notch or an overhanging crown is a stress riser.
• Slag peel: slag that lifts off in long curls on cooling generally signals good heat and correct polarity. Slag that fights the chipping hammer often means current is low.

Symptom-to-Fix Reference

Symptom	Likely cause	Corrective action
Round holes in bead	Moisture, contamination, long arc	Dry rods, clean plate, shorten arc
Dark pockets between passes	Skipped cleaning, bad angle	Chip and brush every pass, adjust drag angle
Bead sits on top of joint	Low amps, fast travel	Raise current, slow down, aim at root
Groove at weld toe	Excess current, long arc	Reduce amps, tighten arc, pause at toes
Arc wandering sideways	Magnetic deflection	Shorten arc, move ground, try AC
High, ropey crown	Slow travel, low heat	Increase speed, verify amperage

Why “Turn It Up” and “Turn It Down” Fall Short

Amperage is one variable in a five-variable system: electrode, current, polarity, arc length, and travel speed. Changing only the dial while the rod is damp or the joint is rusty just relocates the defect. Diagnose first, then adjust one thing at a time.

Visual inspection cannot reliably detect lack of fusion or internal slag, so critical work relies on qualified procedures and nondestructive examination such as ultrasonic or radiographic testing. On scrap you can do better than looking: bend test a butt weld in a vise, break a fillet with a hammer, and cut a cross-section to see your penetration profile. That feedback loop teaches more in an afternoon than a week of guessing. If a defect keeps repeating, stop welding and inspect the setup, the rods, and the machine before blaming your hands.

Safety, Fume, and Compliance: What the Rules Actually Require

Most stick welding safety advice stops at “wear a helmet and don’t burn yourself.” The real hazards sit in four domains: optical radiation, electrical energy, fire, and airborne contamination, each with its own failure mode and controls.

Optical Radiation: The Arc Is an Unshielded Lamp

An open arc throws intense ultraviolet and infrared radiation everywhere. UV burns the cornea and causes “arc eye,” a sand-in-the-eyes pain that hits hours later. Infrared delivers heat to skin and eyes.

The control is a helmet with the right shade. For routine MMAW, most shade charts put the lens at 9 to 12, with higher currents pushing toward the darker end; check a current chart for your electrode and amperage. Auto-darkening lenses must be rated for arc welding and react before UV reaches you.

Arc flash reaches bystanders, so a shared shop needs a screen or curtain. OSHA covers protective equipment for operators and nearby personnel in 29 CFR 1910.252; the welding, cutting, and brazing overview at osha.gov is a solid starting point.

Burns, Spatter, and What Leather Actually Buys You

Stick welding spatters, slag pops, and hot stubs land where you’d rather they didn’t. Cotton and synthetics smolder or melt into skin; leather sleeves, an apron, gauntlet gloves, and boots with real coverage are the baseline. Button the collar, empty your pockets of lighters, and keep gloves dry and intact, because a pinhole is a burn waiting for a reason.

Electric Shock: The Invisible Failure Mode

Open-circuit voltage on many stick machines sits above 50 volts before the arc is struck. Wet skin, sweat-soaked clothing, or a puddle underfoot collapses resistance and raises current through the body. The culprits are boring:

• Cracked or taped insulation on a stinger dragged across concrete
• Bare conductors at the holder, where your hand grips
• Sweat-soaked gloves and damp ground
• A poor work lead connection forcing current elsewhere

Clamp the ground to clean, bare metal close to the weld. A clamp on painted or rusty steel makes a high-resistance joint that heats and arcs. Never use the building frame as a return path or weld on a live workpiece.

Fire Prevention: Permits, Clearance, and the Fire Watch

Slag and spatter land in cracks, behind panels, and inside wall cavities where they can smolder for hours. OSHA guidance calls for combustibles within 35 feet of hot work to be moved or protected, plus a fire watch where conditions warrant. Most permit programs are built on NFPA 51B.

• A written permit before work starts, defining location and task
• Combustibles removed or protected, fire blankets over gaps
• A fire watch during work and for a set period after
• Extinguishing equipment on hand, plus a post-work inspection

Fire watch length and permit validity vary by jurisdiction, so follow the permit.

Fume: The Hazard With No Visible Warning

Welding fume is a mixture of metal oxides and gases formed when electrode, flux, and base metal vaporize into ultrafine particles. In MMAW the flux coating supplies much of the particulate; composition depends on electrode, base metal, coatings, and shielding.

Manganese appears in most carbon steel electrodes and is linked to neurological effects at sustained overexposure. Hexavalent chromium forms when welding stainless and other chromium-bearing alloys and is a recognized carcinogen; OSHA’s 29 CFR 1910.1026 sets a PEL of 5 micrograms per cubic meter as an 8-hour TWA, with an action level at half that.

The bigger picture: the International Agency for Research on Cancer classified welding fumes as Group 1, carcinogenic to humans, in 2017. The NIOSH welding topic page and the NIOSH criteria document on welding fume are useful references.

Ventilation, Extraction, and Why “I’m Outside” Isn’t a Plan

Controls run in a hierarchy. Dilution ventilation moves general air; local exhaust captures fume at the source, before it reaches your breathing zone. Supplied-air respirators are the last line.

Outdoors beats a sealed garage but isn’t automatically sufficient: on a still day, in a corner, or under a tarp, you can overexpose. Confined spaces are worse, because welding inside a tank combines fume with restricted airflow, and argon or CO2 displacement can create an oxygen-deficient atmosphere. Gas monitoring and an entry program are requirements.

For a deeper look at process trade-offs, our breakdown of the advantages of stick welding explains why MMAW stays the go-to in remote and maintenance work.

The Compliance Mindset in One Paragraph

Compliance is not paperwork for its own sake. A hot work permit forces someone to check for combustibles. A fume assessment forces someone to measure what you’re breathing. Each control exists because someone got hurt without it. Follow the stricter of the code or the site rule, and trust the gut feeling that something is wrong.

MMAW vs MIG, TIG, and FCAW: Honest Comparisons and Cost Reality

Choosing a welding process is not a brand-loyalty question. It is a production question. The right process depends on where you are working, what you are welding, how much cleanup you can tolerate, and how quickly the job needs to be finished. MMAW is not the fastest or the cleanest option, but it is often the most practical one.

Four Processes, Four Different Jobs

Each process has a distinct sweet spot. Compare them on the factors that actually affect a buying or scheduling decision:

Factor	MMAW / Stick	MIG	TIG	FCAW
Equipment cost	Lowest	Moderate	Highest	Moderate to high
Portability	Excellent	Fair	Poor	Fair
Wind tolerance	Excellent	Poor with gas shielding	Poor	Good to excellent
Typical thickness	3 mm and up	Thin to medium	Thin	Medium to thick
Out-of-position work	Excellent	Good	Excellent with skill	Good
Deposition rate	Low	Medium to high	Low	High
Cleaning burden	High, due to slag	Low	Very low	Moderate
Skill curve	Moderate	Low	High	Moderate

Where Each Process Genuinely Wins

MIG is the shop favorite for thin sheet and light fabrication. A continuous wire feed plus shielding gas makes it fast, clean, and easy to learn. On 1 mm to 6 mm mild steel, MIG usually beats stick on speed and appearance. The trade-off is wind sensitivity and the need for a gas cylinder, which makes it less convenient in the field.

TIG is the precision tool. It gives independent control of heat and filler, produces very clean welds, and handles thin material and exotic alloys that stick cannot touch. It is also slow, demands good hand control, and needs shielding gas. For appearance-critical stainless or aluminum work, TIG is often the correct answer, even when it is not the cheapest.

FCAW combines the productivity of continuous wire with better outdoor tolerance than MIG. Flux-cored wire offers higher deposition rates than SMAW and is often preferred for long structural welds. Self-shielded versions resist wind well, while gas-shielded versions produce cleaner welds but need gas protection. FCAW is a production process, and its equipment is less portable than a simple stick setup.

MMAW remains the default for maintenance, pipeline, and remote work. The equipment requires only a power source, leads, a holder, and electrodes, which is why it remains practical in locations without a shielding gas supply. It tolerates wind, dirty steel, and rough handling. That durability is the reason stick welding still wins on remote job sites, even where faster processes exist.

The Cost Reality Behind the Arc

Machine price is only the entry ticket. Stick welding’s deposition efficiency is commonly estimated at 60 to 70 percent because slag, spatter, and the unusable stub waste material and time. Every electrode change interrupts the arc. Every pass may need chipping and brushing. SMAW is also generally the least efficient common arc process in operator-factor terms, with only around 25 percent of paid time spent actually welding. The rest goes to setup, cleaning, repositioning, and rod changes.

Duty cycle adds another production limit. A machine that must cool down cannot compete with a continuous wire process during long production runs. Stick is efficient when access matters more than arc-on time. It is inefficient when a fabricator is paid per meter of weld.

Training, Testing, and Career Paths

Most welding careers begin with a mix of formal instruction and supervised practice. Apprenticeships, community college programs, and employer training schemes all teach safety, process setup, and position work. Employers usually apply their own welding tests before hiring for structural or pressure work. Those tests assess the welder, not the certificate on the wall.

That distinction matters. Certification confirms that a training program or certifying body has recognized a skill level. Qualification confirms that a specific welder can produce sound welds under a specific procedure. For structural steel in the United States, the AWS D1.1 Structural Welding Code – Steel governs procedure and welder qualification. A certificate alone does not satisfy that requirement.

Before paying for a course, spend time running beads on scrap plate. Learn how amperage, arc length, and travel speed change the puddle. Arriving with basic arc time makes formal instruction far more valuable, and it helps you judge whether a local program actually provides enough hands-on practice.

Putting It Together: A Practical Learning Path and Final Takeaways

Everything in this guide points to one conclusion: manual metal arc welding rewards a system, not enthusiasm. The welders who improve fastest are not the ones who burn the most rods in a single session. They are the ones who change one variable at a time, on plate of consistent thickness, and write down what happened. Practicing on scrap of the same thickness lets you isolate amperage, then angle, then travel speed, instead of chasing five problems at once and fixing none of them.

Six Stages From First Arc to First Project

Work through these in order. Skipping ahead is the most common reason beginners plateau for months.

Stage	Time per session	What success looks like
1. Safety and PPE setup	1 hour, once	Shaded helmet, leathers, gloves, boots, screens, extinguisher, and a clean, dry work area in place
2. Machine familiarization	1 hour	You can set polarity, dial amperage, identify duty cycle, and strike an arc on command
3. Bead pads on flat plate	4–6 sessions of 45 minutes	Straight, overlapping beads with even ripples and slag that peels cleanly
4. T-joints	4–6 sessions	Consistent fillet size, wetted toes, no undercut on either leg
5. Vertical up	6–8 sessions	No slag traps, controlled puddle, bead width under three rod diameters
6. Real project	Weekend	Square, sound joints on a cart, gate, or repair bracket that you would trust to load

The Five Decisions That Decide Weld Quality

Almost every beginner problem traces back to five variables. Before you blame the machine, check these in order:

• Electrode selection — does the rod match the steel, position, and current available?
• Amperage — hot enough to fuse, cool enough to control.
• Polarity — DCEP, DCEN, or AC, as the classification requires.
• Arc length — short enough to protect the pool, long enough not to stub out.
• Travel speed — fast enough to avoid a tall, cold bead, slow enough to fuse the toes.

Pre-Weld Checklist

• Electrode dry, correct type, and within its exposure limits
• Amperage set for rod diameter and material thickness
• Polarity verified at the machine, not assumed
• Ground clamp on clean, bare metal close to the joint
• Stinger insulation intact, cable connections tight
• Base metal cleaned to bare metal; joint fitted, beveled, and tacked
• Work area clear of combustibles; screens in place

Post-Weld Inspection Checklist

• Chip all slag, then look again — slag hides everything
• Check bead profile: convex, flat, or dished, and whether the toes wet in
• Look for undercut, porosity, spatter clusters, and arc strikes
• Confirm crater is filled and tie-ins are blended
• Measure leg size or reinforcement if the drawing specifies it
• Log the settings you used so the next session starts from data

When to Stop Practicing Alone

Self-teaching has a ceiling, and it usually appears around vertical-up work, where small errors in arc length and pause time are hard to see in your own beads. Book hands-on instruction once you can run a consistent flat bead and a reasonable T-joint. When comparing courses, ask three questions: how much arc-on time per student, what processes are taught, and whether the instructor has current field or shop experience. A course covering related processes is worth a look too, such as this aluminium welding course overview for anyone broadening beyond carbon steel. Remember that welder qualification is demonstrated through a performance test to a code such as AWS D1.1, and that is separate from holding a certificate from a training institution.

Why MMAW Still Earns Its Place

Stick welding remains a standard training process precisely because it offers no automatic wire feed to hide behind. You must manage arc length, puddle, and heat by hand, every second. Those skills transfer directly to MIG, TIG, and flux-cored work, which is why the advantages of stick welding extend well beyond the jobsite into how you read a weld pool for the rest of your career. Wire feed and robotics have not made that obsolete; they have made it more valuable as a foundation.

Be realistic about volume. Progress comes from plate time, measured in hours and boxes of rods, not in tutorials watched. Nobody produces code-quality welds in a weekend, and almost everyone who sticks with it for a few months of regular practice does. Set up cleanly, change one variable per session, keep notes, and let the bead pad tell you the truth.

Frequently Asked Questions

Is MMAW the same as stick welding?

Yes. Manual metal arc welding (MMAW) is the same process as shielded metal arc welding (SMAW), which most welders call stick welding. The differences are only in naming convention and regional usage, not in how the process works.

What is the difference between E6013 and E7018?

E6013 is a general-purpose rutile electrode with an easy arc and good appearance, well suited to thin steel and beginner practice. E7018 is a low-hydrogen electrode with higher tensile strength, better toughness, and much stricter moisture control, and it is the standard choice for structural and critical work.

Can I use E7018 on AC?

Yes, E7018 is designed to run on AC or direct current electrode positive. Some electrodes in the E7018 family are optimized for one or the other, so check the manufacturer’s data sheet for the specific brand before setting up.

Why does my electrode keep sticking to the workpiece?

Sticking usually means the amperage is too low for the electrode diameter, the arc was started with too much pressure, or the rod is damp. Increase current slightly, use a lighter tap or scratch motion, and check that the electrodes have been stored properly.

How thick can manual metal arc welding go?

There is no hard upper limit, because thick sections are welded with multiple passes, bevels, and preheat. The practical lower limit is the bigger constraint: below roughly 3 mm (1/8 inch), burn-through and distortion become difficult to control with stick welding.

Do I need shielding gas for MMAW?

No. The electrode’s flux coating decomposes in the arc to produce the shielding gas and the slag layer that protects the weld. That self-shielded design is a major reason stick welding works well outdoors and in remote locations.

Is welding fume from stick welding dangerous?

Yes, welding fume is a recognized health hazard. IARC classifies welding fumes as Group 1 carcinogenic to humans, and fume can contain manganese, hexavalent chromium from stainless, and other metal oxides. Use ventilation or fume extraction, wear appropriate respiratory protection, and follow your employer’s exposure control program.

How long does it take to learn stick welding?

Most people can run a passable flat bead after a few focused practice sessions, but consistent out-of-position work typically takes months of regular plate time. Structural welder qualification tests demand considerably more practice than hobby-level competence.

Why is my weld full of holes?

Holes in the bead usually indicate porosity, caused by moisture, oil, paint, rust, or galvanizing in the weld zone, an excessively long arc, or damp electrodes. Clean the joint to bare metal, use dry electrodes stored correctly, and tighten the arc length.