Arc Welding Electrode Diagram: Parts, Types & How to Read It

A DIYer stands in the welding aisle holding two nearly identical 3/32 in. rods, one marked E6013 and one E7018, with no idea which end is which or what the numbers mean. Ten minutes with a proper arc welding electrode diagram turns that confusion into confident, safe welding.

What an Arc Welding Electrode Diagram Actually Shows

Picture yourself in the welding aisle holding two rods, both 3/32 in., one stamped E6013 and the other E7018. Each has a bare steel end and a chalky gray sheath. You need to choose, but no one is there to explain which end goes in the holder or what the numbers mean.

That moment is why an arc welding electrode diagram exists. A good diagram does two things. First, it labels the physical parts of a stick electrode in cross-section so you see the metal core, the flux covering, and how the code relates to both. Second, it labels the arc circuit the electrode works inside, from the power source and cables through the holder, arc, weld pool, slag, and heated base metal. One shows what the rod is; the other shows what it does once you strike an arc.

What SMAW Actually Is

Stick welding is shielded metal arc welding (SMAW). The American Welding Society and OSHA define it as a process that uses a consumable metal electrode covered with flux, with the heat of an electric arc melting both electrode and base metal to form a joint. As the flux burns, it produces shielding gas and slag that protect the molten puddle from oxygen and nitrogen. Without that protection, the weld becomes porous and brittle. SMAW works outdoors in wind, on dirty or rusty metal, in any position, and with simple equipment that can run off a generator. For more details, see Advantages of Stick Welding: Why SMAW Still Wins.

The Two Diagrams This Article Walks Through

Two figures cover almost every stick welding question:

• Diagram 1: Electrode cross-section. Shows the bare contact end (gripped by the holder), the extruded flux covering, the steel core wire running the length, and the classification code stamped at the tail. It typically shows core wire diameter versus overall diameter.
• Diagram 2: Arc circuit. Shows the power source, electrode holder (stinger), welding cables, work clamp, the electrode, the arc, the weld pool, the floating slag layer, the base metal, and the heat-affected zone spreading from the fusion line.

Key Terms You Will See Labeled

These terms appear on most diagrams:

• Electrode: the consumable rod (assembly).
• Core wire: the metal center that becomes filler and carries current.
• Covering (coating): the extruded flux layer around it; flux is the chemical mixture.
• Slag: the solidified glassy crust that floats on the puddle and protects it while cooling.
• Arc: the plasma discharge between electrode tip and work.
• Weld pool (puddle): the molten metal reservoir you steer.
• Heat-affected zone (HAZ): the band of base metal next to the weld that never melted but had its microstructure and properties changed by heat.

What You Will Be Able to Do After Reading

After reading, you should be able to read any classification code on a rod and name its tensile strength, welding position, coating family, and compatible current. You should be able to match an electrode to base metal, thickness, and joint position, and explain why structural code work often calls for E7018. You should be able to diagnose a bad-looking weld by tracing the problem back to the diagram (moisture in low-hydrogen rods, wrong polarity, arc held too long). And you will know the safety layer in every diagram, including the OSHA requirement in 29 CFR 1910.252 that welders use helmets or hand shields with suitable filter plates during all arc welding.

Scope Notes Before We Cut the Rod Open

Classification codes and cross-section geometry discussed here come from AWS A5.1/A5.1M:2025 (carbon steel covered electrodes for SMAW). Stainless, hardfacing, and cast iron electrodes follow parallel AWS specifications. Stick welding is one route to a fusion joint; if your work involves aluminum, the filler and shielding logic differ, so processes like aluminum flux core welding or MIG deserve their own diagrams. Everything below assumes a carbon steel stick electrode in an SMAW circuit.

Anatomy of a Stick Electrode: Walking Through the Cross-Section Diagram

A stick electrode is not a plain metal rod with paste smeared on it. Cut one in half and the picture changes completely: you’re looking at a composite consumable with two separate parts doing two different jobs. A cross-section diagram shows a solid filler-metal core wire running the full length of the rod, wrapped in a thick, extruded flux covering designed to burn away during welding. The wire turns into weld metal; the covering turns into shielding gas, slag and arc chemistry. It’s a big part of why SMAW remains so stubbornly practical in the field — see our advantages of stick welding guide for the fuller case.

What a Cross-Section Drawing Actually Shows

A cross-section is a cutaway view, as if a hacksaw sliced the rod at a right angle and you peered at the exposed face. In a labeled version you’ll see concentric rings: a solid circle in the middle (the core wire), a thick ring around it (the flux covering), and callouts pointing at both ends. Because the covering is extruded — raw flux ingredients mixed with binders and pushed through a die onto the wire, then dried — it sits at fairly uniform thickness over the whole rod. A dipped or painted coating would look uneven and thin by comparison. Stainless and alloy wires follow the same construction with different core chemistry; the alloy steel welding electrodes breakdown covers those variations.

Every label on a good cross-section drawing points to something you can actually see and touch:

• Core wire — the steel filler metal that melts into the weld pool.
• Flux covering — the extruded outer layer that shields, stabilizes and cleans the arc.
• Bare contact end — the short uncovered stub where the electrode holder grips.
• Arc end — the working end that faces the workpiece and melts back as you weld.
• End markings — the AWS classification printed or stamped near the gripping end.
• Diameter callouts — core wire size and overall (covered) size.

Core Wire Diameter vs. Overall Diameter: Reading the Numbers

This is where most beginners misread the diagram. When a rod is sold as 1/8 in., that nominal size refers to the core wire, not the finished rod. The covering sits on top, so the outside diameter measures noticeably larger — a 1/8 in. electrode drawn to scale shows an overall diameter closer to 5/32 in. Read them as a pair: core wire tells you how much filler you’re depositing and what current range is sensible; overall diameter tells you what the rod physically feels like in your hand.

Standard diameters run 1/16, 3/32, 1/8, 5/32 and 3/16 in. (roughly 1.6, 2.4, 3.2, 4.0 and 4.8 mm), and the coating thickness drawn on the diagram hints at the electrode family. A heavy, iron-powder-rich covering like the kind on an E7024 looks fat next to the lean covering on an E6010. Heavier covering means faster deposition but generally limits you to flat and horizontal positions, which is why all-position welding rods tend to have slimmer coatings.

The Bare End: Where the Diagram Meets the Electrode Holder

The uncovered stub at one end is the gripping end. The electrode holder’s jaws need clean, direct metal-to-metal contact to carry welding current; clamp onto flux instead and you get poor contact, arcing inside the jaws and a burned, pitted holder. A little bare length left after clamping also gives you a safe place to re-strike on scrap. The other end, fully covered, is the arc end, and the printed AWS classification lives near the gripping end so you can identify the rod without flipping through the box.

How the Covering Burns Back During Welding

As the arc runs, the covering is consumed at roughly the same rate as the core wire melts, leaving a small collar of flux around the end of the wire. That collar acts like a tiny gas cup, channeling the shielding gases it generates straight over the arc and molten pool. At the same time, part of the flux melts into a liquid layer that floats on the pool and hardens into slag. Watch a pass and you’ll see the covering retreat toward the holder, the printed markings get closer to the jaws, and the exposed core wire shorten. When the bare stub reaches the holder, the electrode is finished — a fresh rod goes in and the pass continues.

Figure Caption: Label Your Own Diagram

To lock the anatomy in memory, sketch a rod and label it exactly like a figure caption:

1. Overall diameter (covered size, e.g. 5/32 in.)
2. Flux covering — extruded, uniform thickness
3. Iron-powder-rich zone (heavy-duty types only)
4. Core wire diameter (nominal rod size, e.g. 1/8 in.)
5. Printed AWS classification marking
6. Bare contact/gripping end for the electrode holder
7. Arc end — covering recedes here as the rod is consumed

With the parts labeled, the next question answers itself: what is that covering actually doing chemically? That’s the subject of the following section.

What the Flux Coating Does: The Chemistry Behind the Diagram Labels

On the cross-section diagram, the outer layer hugging the core wire is labeled covering (most welders just call it flux). It looks like a plain gray sleeve, but it is the most chemically engineered part of the electrode. Bare steel wire would give a chaotic, contaminated, unstable arc. The covering is what turns a plain metal rod into a controlled welding tool.

Five Jobs Packed Into One Coating

Every function labeled on a stick electrode diagram traces back to the covering doing one of these five things:

• Shielding gas generation. Arc heat decomposes the covering into a cloud of gases (typically carbon dioxide, water vapor, and compounds of sodium, potassium, and titanium). That envelope surrounds the molten pool and pushes away atmospheric oxygen and nitrogen, which would otherwise embrittle and contaminate the weld.
• Slag formation. The molten mineral portion forms liquid slag that floats on the weld pool. Lighter than molten steel, it rides the surface and shields the liquid metal while it solidifies. Once the bead hardens, you chip that crust off to reveal the weld underneath.
• Arc stabilization. Certain compounds in the covering ionize easily, helping the arc hold a steady conductive path between the rod tip and the workpiece. This is why a well-formulated electrode arcs smoothly at lower amperes, while a bare rod spatters and sticks.
• Alloy additions. The covering can carry powdered ferroalloys and deoxidizers. Once these enter the weld pool they change the composition and mechanical properties of the deposited metal, which is how an electrode achieves a specified tensile strength.
• Current conduction and arc efficiency. Iron powder in some coverings carries part of the welding current through the side of the rod, boosting deposition rate and arc efficiency. The coating burns back roughly evenly with the core wire.

What Actually Happens, Layer by Layer

Watch a rod burn in slow motion and the diagram comes alive:

1. The covering at the arc end vaporizes first, releasing shielding gas and liquid slag.
2. The exposed core wire melts into fine droplets that cross the arc and transfer into the base metal.
3. The weld pool forms, alloyed and deoxidized by ingredients from the covering.
4. Slag floats on top of the solidifying pool and freezes into a brittle crust that protects the hot bead as it cools.
5. The covering continues burning back slightly ahead of the melting core wire, feeding fresh shielding gas and slag-formers into every second of the weld.

That last point explains a detail visible on any good diagram: the covering burns back a bit faster than the core wire, exposing a small amount of bare wire at the arc. If it burns back too slowly, the arc wanders; too fast, and you lose protection.

The Health-Warning Layer: What the Diagram Doesn’t Show

Here’s the layer no cross-section drawing prints in color: some covering ingredients are hazardous. Fluxes, coatings, coverings, and filler metals can contain fluorides, silicates, manganese, chromium, and other compounds that produce irritating or toxic fumes when burned in the arc.

That’s why OSHA’s welding standard, 1910.252(c)(1)(iv), requires employers to include potentially hazardous materials in fluxes, coatings, coverings, and filler metals in their hazard communication program, complete with labels and safety data sheets. Filler metals and fusible granular materials must also carry a minimum notice stating that they should not be used in areas without adequate ventilation, referencing ANSI Z49.1, Safety in Welding, Cutting, and Allied Processes, published by the American Welding Society. Read that notice on your next rod carton; it’s printed there because the flux itself is part of the hazard picture.

The health stakes are real. NIOSH lists welding fumes as a potential occupational carcinogen, with lung cancer as the identified cancer site. NIOSH also documents metal fume fever, a flu-like condition from inhaling freshly generated metal oxides, with symptoms including cough, muscle pain, fever, and chills. Galvanized steel is the classic trigger, but any flux-covered rod can deliver a dose in bad ventilation.

Short Note: Treat the covering as a chemical product, not just insulation. Store rods dry, respect the SDS, and never dismiss fumes as “just part of welding.” Our Alloy Steel Welding Electrodes: Selection, Use & Safety guide walks through the same hazard logic for specialty alloys, where the fume chemistry gets even less forgiving. We’ll cover ventilation rates, hoods, and filter shades in detail later in Arc Welding Electrode Diagram: Parts, Types & How to Read It‘s safety section.

Why This Matters When You Read a Diagram

Once you understand the covering’s chemistry, electrode choices stop being guesses. A rutile (titanium dioxide) covering means easy arc starts and smooth beads for beginners. A cellulose covering means digging penetration for dirty metal and root passes. A low-hydrogen covering means crack-resistant structural welds. Every label on the cross-section diagram is really a promise about how the weld will behave. Read the chemistry, and you read the electrode.

How to Read the AWS Classification Code: E7018 Decoded Digit by Digit

Pick up any stick electrode and you will find a short code stamped along the flux near the bare end: E6013, E7018, E7014, E308-16. That code is not a product number or a batch label. It is a compressed specification sheet. Once you know how the American Welding Society (AWS) arranges it, you can read a rod’s minimum tensile strength, welding positions, covering chemistry and compatible currents without opening the package. It is the single most useful skill an all-position welding rod guide can give you.

The Four Slots in the Code

Start with the letter. In the AWS system the E prefix stands for electrode, a covered consumable that carries welding current through the arc. A bare or spooled wire gets an ER prefix instead, for “electrode or filler,” which is why a MIG spool reads ER70S-6 while a stick rod reads E7018.

Code position	What it tells you	E7018 example
Letter	Product type	E = covered stick electrode
First two digits	Minimum tensile strength of deposited weld metal, in thousands of psi	70 = 70,000 psi (about 480 MPa)
Third digit	Welding positions allowed	1 = all positions (flat, horizontal, vertical, overhead)
Fourth digit	Covering type and compatible current	8 = iron-powder low hydrogen, AC or DC

E7018 therefore decodes as: an electrode with 70,000 psi minimum tensile strength, usable in all positions, with a low-hydrogen iron-powder covering that runs on alternating or direct current. The strength digits scale in the same pattern: E60xx means 60,000 psi, E80xx means 80,000 psi, and low-alloy classifications reach E100xx and beyond under the A5.5 alloy steel electrode family.

What the Third Digit Really Means

The position digit has only two values you will meet. A 1 means the electrode is qualified for all four positions, which is what you want for overhead, vertical-up pipe and out-of-position repair. A 2 restricts the rod to flat and horizontal work, usually because its heavy iron-powder covering produces too much molten metal to hold against gravity. That single digit is why E7024 is a production flat-fillet rod and E7018 is the field rod.

What the Fourth Digit Means

The final digit is the covering family plus the current it was designed for. The values you will actually see in a welding supply house are:

• 0 and 1 — high cellulose coverings. E6010 (sodium, DC electrode positive only) burns fast with deep, forceful penetration and a coarse arc; E6011 is the potassium version that also runs on AC.
• 2 and 3 — high rutile (titanium oxide) coverings. E6013 is the classic example: a soft, stable arc, easy restart, light penetration, AC or DC.
• 4 — iron powder added to a rutile covering. E7014 lays down metal faster because part of the current travels through conductive iron powder in the covering.
• 5, 6, 7 and 8 — low hydrogen coverings. E7015, E7016, E7018 and E7028. The chemistry is baked in a controlled environment to keep moisture, and therefore hydrogen, out of the weld.

Common Classifications at a Glance

Classification	Min. tensile	Position	Covering / current	Typical use
E6010	60,000 psi	All	High cellulose sodium; DC+	Pipe root passes, deep penetration on dirty plate
E6011	60,000 psi	All	High cellulose potassium; AC or DC+	Same roles on AC-only machines, farm repair
E6013	60,000 psi	All	High rutile potassium; AC or DC+	Sheet metal, thin tube, beginner practice
E7014	70,000 psi	All	Iron powder rutile; AC or DC+	Fast fillet and groove work on clean steel
E7018	70,000 psi	All	Iron powder low hydrogen; AC or DC+	Structural steel, pressure vessels, pipe, code work
E7024	70,000 psi	Flat / horizontal	Iron powder rutile; AC or DC+	High-deposition flat fillets and horizontal butts
E308-16	Specified in A5.4	All	Titania; AC or DC	Welding 304-type stainless under AWS A5.4

Note how the stainless code differs. In E308-16 the “308” identifies the filler metal type rather than a tensile figure, matching 308 filler to 304 stainless, while the -16 suffix describes the covering and current. Stainless classifications also use -15, -17 and -25 suffixes in the same way.

Where the Code Comes From: the AWS A5 Series

Each classification lives inside an AWS filler metal specification. The carbon steel stick electrodes in the table above are covered by AWS A5.1/A5.1M, with the 2025 edition currently published alongside the newer A5.1/A5.1M:2026 revision. A5.1 sets the chemistry, mechanical property, testing and usability requirements every manufacturer must meet before an electrode may carry the classification. Its neighbours in the same family include:

• A5.2 — carbon steel and iron rods for oxyfuel welding.
• A5.4 — stainless steel electrodes for SMAW, home of E308-16.
• A5.5 — low-alloy steel SMAW electrodes.
• A5.17 — electrodes and fluxes for submerged arc welding.
• A5.18 — carbon steel electrodes and rods for gas-shielded arc welding, the ER70S series.

The complete AWS filler metal specification index lists the whole family, and each spec prints the same classification logic in its scope section.

Practically, every time you read the four-digit code you are reading the same shorthand an engineer writes into a welding procedure. Learn it once, and the label on the rod, the drawing on the bench and the specification in the paperwork all speak one language.

Electrode Types by Coating: Rutile, Cellulose, Low Hydrogen and Iron Powder

If the cross-section diagram shows what a stick electrode is made of, the coating family tells you how it will behave in the arc. Two 1/8 in. rods can look identical through the flux covering and still weld completely differently. The difference is chemistry, and AWS has codified that chemistry so a classified rod performs the same way no matter who made it. Under AWS A5.1, any E7018 sold as E7018 must meet defined requirements for deposited weld metal chemistry, mechanical properties, and usability, including positional and current capability.

What the Fourth Digit Tells You About the Covering

That fourth digit is the covering-type symbol, and it is the fastest way to read a rod off the diagram without guessing:

Digit	Covering family	Typical rods	Current
0	High cellulose sodium	E6010	DC reverse (electrode positive)
1	High cellulose potassium	E6011	AC or DC
3	High titania (rutile)	E6013	AC or DC
4	Iron powder, titania	E7014, E7024	AC or DC
5 / 6	Low hydrogen sodium / potassium	E7018	DC (5) or AC/DC (6)
8	Iron powder, low hydrogen	E7028	DC reverse

Cellulose Rods: E6010 and E6011

Cellulose coverings are loaded with organic material that burns into a forceful, contracting stream of shielding gas. The result is deep, narrow penetration that burns through dirt, rust, paint, and gap-heavy fit-up. E6010 runs DC only and is the classic root-pass rod for open-root pipe and positional work. E6011 is the same cellulose chemistry with potassium added so the arc also runs on AC, which makes it the friendlier option on old transformer machines. Both are hot, spattery, and produce a thin slag that lifts off easily.

Rutile Rods: E6013 and E7014

Rutile (titanium dioxide) coverings prioritize a smooth, stable, forgiving arc with low penetration and a fluffy slag that peels cleanly. E6013 is the rod most beginners learn on: it runs on AC or DC, tolerates a slightly long arc, and produces attractive ripples on sheet and light framing. Adding iron powder to the rutile covering gives you E7014, which deposits metal faster and cleans up quicker, a genuine productivity gain on medium plate and repair work where penetration demands are moderate. It is worth reading our all position welding rod guide if you need to run these rods overhead or vertical, since position capability is a separate classification digit.

Iron Powder Rods: E7024 and E7028

Iron powder can make up 25 percent or more of the covering weight, and nearly all of it ends up in the weld rather than the spatter can. E7024 is the flat-and-horizontal speed demon for heavy fillet welds, while E7028 combines iron powder with a low-hydrogen base for high-efficiency production welds in the flat position. Both deposit fast; neither is meant for overhead work.

Low Hydrogen Rods: E7018 and Why They Live in a Heated Quiver

Low hydrogen coverings, particularly low hydrogen potassium formulations, are engineered to keep diffusible hydrogen out of the weld metal. Hydrogen is the trigger in hydrogen-induced cracking: it migrates into the cooling weld, collects at stress points and grain boundaries, and can open a crack hours after the bead looked perfect. That is why E7018 rods are baked and sealed at the factory, then stored in heated quivers or ovens at the shop. A rod that has soaked up atmospheric moisture reintroduces the problem, showing up as porosity, coarse ripples, and in the worst case, delayed cracking in restrained joints.

Matching the Coating to the Job

As a working rule: root passes and dirty pipe get cellulose, sheet metal and beginner practice get rutile, flat production fillets get iron powder, and structural or restrained joints get low hydrogen. The coating also dictates ventilation planning, because every covering makes fumes. OSHA 1910.252 requires mechanical ventilation at a minimum rate of 2,000 cubic feet per minute per welder in spaces holding less than 10,000 cubic feet per welder or rooms with ceilings under 16 feet. Covering chemistry is also why alloy work deserves its own rod choice; our alloy steel welding electrodes guide covers that matching logic in detail.

Read the fourth digit first, then the position digit, and the coating family will tell you almost everything about penetration, deposition rate, cleanup, and storage before you ever strike an arc.

The Arc Welding Circuit Diagram: How the Electrode Fits the Whole System

An arc welding electrode diagram is more than a picture of a stick rod. It is a map of the electrical circuit that allows an arc to form. For shielded metal arc welding (SMAW), that circuit must stay closed from the power source all the way back to complete the weld. Understanding it is key to controlling penetration, deposition, and safety.

Components of the Arc Welding Circuit

Every SMAW setup relies on the same loop of current. The main parts include:

• Power source: A constant current (CC) machine, which helps keep amperage stable even as arc length changes.
• Electrode holder: An insulated clamp that grips the electrode and carries current to its tip.
• Welding cables: Heavy gauge conductors that move current between the machine, holder, and work clamp.
• Work clamp (ground): Attached to the base metal or work table to close the circuit.
• The electrode: A consumable rod that conducts current and melts to provide filler metal, while its flux creates shielding.
• The arc and weld pool: The arc generates the heat to melt metal, forming a weld pool that solidifies into the bead.
• Slag and HAZ: The flux forms a slag layer for protection, while the heat-affected zone (HAZ) is the nearby base metal altered by heat without melting.

If any of these links are loose or poorly grounded, voltage drops can occur and make a stable arc nearly impossible.

Polarity: Reverse vs Straight Wiring

Where you connect the holder and work clamp determines polarity, and that choice directly affects how heat is distributed across the weld.

Polarity	Connection	Typical Effect on Weld	Common Electrodes
Electrode-positive (reverse polarity, DCEP)	Electrode holder to (+), work clamp to (-)	Deeper penetration, more heat into the base metal, faster burn-off	E6010, E7018, many low hydrogen and cellulosic rods
Electrode-negative (straight polarity, DCEN)	Electrode holder to (-), work clamp to (+)	Shallower penetration, more heat in the electrode, higher deposition rate	E6012, and certain rods used to limit burn-through on thinner material

Many electrodes are rated for AC or DC, but their performance can shift with polarity. Always check the manufacturer’s classification before changing your connections.

Amperage, Duty Cycle, and Cable Routing

Three practical factors are just as vital as polarity. First, amperage controls heat and deposition. Too low and the electrode will stick, too high and you risk excess spatter and undercut. Stick to the recommended amperage range for your electrode diameter.

Second, duty cycle is the percentage of a 10-minute period a machine can run at a given output without overheating. For example, a 60% duty cycle allows 6 minutes on and 4 minutes off at rated current. Exceeding that limit can overwork the machine.

Third, cable routing is a matter of both equipment and people. Cables should remain untangled, clear of sharp edges or hot surfaces, and kept off the floor when possible.

Safety Requirements for the Circuit

Because the circuit carries live current, safety is built into its use. A few key requirements apply to SMAW:

• Shutdown discipline: According to OSHA 1910.252, when welding is suspended for a substantial period, such as lunch or overnight, all electrodes must be removed from the holders and the machine disconnected from its power source.
• Eye and face protection: A helmet or hand shield with the correct filter shade is required for all arc welding. Per OSHA’s welding-cutting-brazing rules, shade 10 is typical for SMAW with 1/16 through 5/32 in. electrodes, and shade 12 for 3/16 through 1/4 in. electrodes.
• Clear work areas: Welding cables and equipment must be kept clear of passageways, ladders, and stairways to prevent both tripping hazards and damage to insulation.

With the basics covered, it’s easier to match your setup to the job. For a broader look at the process, check out Advantages of Stick Welding: Why SMAW Still Wins. For specific rod families, see Alloy Steel Welding Electrodes, or for multi-position work, reference the All Position Welding Rod Guide.

At its core, the arc welding circuit diagram shows the electrode for exactly what it is: one link in a closed loop. Keep that loop secure, dial in your polarity and amperage, respect your duty cycle, and follow safe shutdown practices to get a sound weld every time.

Choosing the Right Electrode: Matching the Diagram to Base Metal, Thickness and Position

The cross-section diagram tells you what a stick electrode is made of. The classification code tells you how it behaves. Put those two together and you have everything you need to pick the right rod out of the box at the supply house. Electrode classification encodes both minimum tensile strength and position capability, so selection always starts with the weld properties the job actually demands, not with whichever rod happens to be cheapest. That is one reason stick welding refuses to die on jobsites, as our look at the advantages of stick welding explains: one machine and a small pack of rods covers an enormous range of work.

A Four-Step Selection Workflow

Run through these steps in order and the right electrode usually narrows itself down:

1. Identify the base metal and its thickness. Mild steel, stainless, cast iron, alloy steel, and aluminum all demand different filler families. Thickness matters because thin sheet punishes excessive penetration while thick, restrained joints punish hydrogen.
2. Decide the welding position. If the joint is flat and you can get to both sides, you can use high-deposition flat-only rods. Overhead, vertical, or out-of-position pipe work requires an all-position electrode. Our all position welding rod guide digs deeper into that choice.
3. Check what your machine can actually deliver. A basic AC buzz box cannot run a DC-only E6010 or most E7018s. Confirm available current and polarity before falling in love with a rod.
4. Match the classification to the requirements. Tensile strength, position digit, coating type, and current suffix should all line up with steps one through three.

Common Mild Steel Electrodes Compared

Electrode	Penetration	Position	Current	Typical uses	Limitations
E6010	Deep, forceful	All	DC electrode positive	Pipe root passes, root passes on positional pipe, light rust or coating	Harsh arc, heavy spatter, tricky for beginners
E6011	Deep	All	AC or DC	AC-only machines, farm repair, pipe roots, rusty stock	Rough ripples, coarse bead appearance
E6013	Moderate	All	AC or DC	Sheet metal, thin tubing, cosmetic welds, practice	Too shallow for thick or structural joints
E7014	Moderate	All (large diameters flat/horizontal)	AC or DC	Production fabrication, faster fill on clean steel	Not low hydrogen; skip on critical or root welds
E7018	Moderate	All	DC electrode positive (some AC variants)	Structural steel, pipe fill and cap, pressure work	Ruined by moisture; won’t burn through grease or heavy rust
E7024	Moderate to light	Flat and horizontal only	AC or DC	High-deposition horizontal fillets, tank and plate work	Flat/horizontal only, heavy slag blanket

Matching Filler Metal to the Base Metal

The base metal family decides the filler-metal specification before it decides the exact rod. Mild steel pairs with the carbon steel SMAW electrodes under AWS A5.1/A5.1M. Cast iron generally moves to nickel-based electrodes, stainless to the A5.4 family such as E308-16, and alloy steels to their own specification family, which we cover in detail in our guide to alloy steel welding electrodes. Aluminum is the outlier: stick electrodes for aluminum exist, but most aluminum work has migrated to wire processes, as our piece on aluminum flux core welding makes clear.

Across all of these, the AWS filler-metal specifications catalog organizes standards by material and welding process, covering SMAW, submerged arc welding, and the gas-shielded processes in one place. Browsing the AWS filler metal specifications catalog is the fastest way to confirm you are buying from the correct family.

Thickness, Preheat and Post-Weld Requirements

As sections get thicker, two things change. First, the joint cools faster and shrinks harder, raising the risk of cracking. Second, hydrogen embrittlement becomes a real threat. That is why thicker, restrained, or cold-weather joints usually require preheat, controlled interpass temperature, and sometimes post-weld heat treatment. The AWS D1.1/D1.1M:2025 Structural Welding Code – Steel covers design, welding procedures, qualification, fabrication, inspection, and repair of welded steel structures, and its preheat requirements are driven by material thickness, steel chemistry, and joint restraint. Check the applicable AWS D1.1/D1.1M:2025 Structural Welding Code before welding anything over roughly 3/8 in. on a critical joint.

Why Structural Jobs Specify E7018

On structural steel, E7018 shows up in weld procedure specifications for a reason. It is a low-hydrogen electrode with sound mechanical properties, smooth bead profile, and all-position capability in smaller diameters, and it pairs with the prequalified joint details in D1.1. Contractors keep it in heated quivers and ovens because the very property that makes it safe, low hydrogen in the covering, is destroyed by moisture pickup. The bottom line: read the diagram, read the code, and let the base metal, thickness, and position pick the rod for you.

Reading the Diagram Safely: Ventilation, Eye Protection and Fume Control

Every label on an arc welding electrode diagram is quietly a safety label too. The covering that shields the puddle also puts metal oxides, gases, and particulates into the air you breathe. The current you dial in to get the penetration the diagram promises also changes how much fume comes off the arc. So before you trust a diagram enough to strike an arc, read the safety layer underneath it.

Eye and Face Protection: The First Line

OSHA requires welders to use helmets or hand shields with suitable filter lenses during all arc welding, cutting, and brazing operations, as set out in 29 CFR 1910.252. The filter shade tracks the electrode size and the amperage you are actually running: a small rod on light current wants a lighter lens, while a 1/8 in. E7018 pushed at 130 amps wants a much darker one. Follow the manufacturer’s shade chart rather than a favorite color, and add a clear cover lens plus proper side shields so spatter, UV, and IR cannot slip around the edges of the hood. Glancing under the helmet to check the puddle is one of the fastest ways to get arc flash.

Local Exhaust: Placement Beats Raw Power

Here the rules get specific. Local exhaust hoods must be placed as near as practicable to the arc, and airflow in the welding zone must hold 100 linear feet per minute (fpm) at the hood’s most remote distance from the work. That 100 fpm number is the practical target: it is the capture velocity that pulls the plume away before it reaches your breathing zone, no matter how big the fan is (OSHA welding, cutting, and brazing hazard solutions).

Rough hood sizing looks like this:

Hood distance from the arc	Airflow typically required
4–6 in. away	About 150 cfm
10–12 in. away (3 in. hood)	About 600 cfm

Move the hood closer and you can cut the required airflow dramatically. When natural ventilation alone cannot keep fume levels below the exposure limits, mechanical exhaust or respiratory protection becomes mandatory, not optional.

The Fume Numbers That Actually Matter

Welding fume is not one chemical. It is a mix of base-metal oxides, coating decomposition products, and gases, and its composition changes with the electrode you choose. NIOSH reports that welding fumes contain manganese, and it publishes specific exposure limits for that fraction: a recommended exposure limit (REL) of 1 mg/m³ as a time-weighted average over a 10-hour shift, a short-term exposure limit (STEL) of 3 mg/m³ over 15 minutes, and an IDLH (immediately dangerous to life or health) concentration of 500 mg/m³ (NIOSH Pocket Guide: manganese). OSHA’s permissible exposure limit for manganese is higher: 5 mg/m³ as a ceiling (NIOSH welding topic page).

Those numbers are worth memorizing because manganese is what welders overexpose to most often, and neurological symptoms creep up slowly. Chronic exposure shows up as hand tremor, gait changes, and mood effects long after the welding stopped.

Special Metals Need Special Controls

Some jobs escalate beyond routine fume extraction. Stainless steel arc welding can produce chromium, including hexavalent chromium, which needs dedicated exposure monitoring and often respiratory protection. Cadmium work demands ventilation so effective that many shops refuse the job rather than improvise. Beryllium and lead require tight controls plus biological monitoring for lead. Burning zinc galvanizing causes metal fume fever, the classic chills-and-fever reaction that follows a day welding on coated steel. Each of these has its own OSHA guidance under the agency’s welding, cutting, and brazing program.

Confined Spaces and First Aid

A welding electrode diagram changes completely when the arc is inside a tank, pit, or vessel. Confined-space work requires atmospheric testing before entry, continuous forced ventilation, an attendant outside, and a written permit depending on the space. Oxygen-deficient or enriched atmospheres make an arc strike lethal.

Finally, OSHA requires first-aid equipment to be available at all times during welding operations, with all injuries reported as soon as possible. That sounds basic until a hot spark lands under a sleeve and nobody notices because the shop has one first-aid kit behind a locked door. Check that yours is reachable, stocked, and that your all-position welding rod work is not being done alone without someone who can call for help.

Common Electrode Mistakes and Diagram-Reading Errors (and How to Fix Them)

Most stick welding problems start long before the arc does. They start when someone misreads the electrode diagram, grabs the wrong rod, or sets the machine by ear instead of by the manufacturer’s chart. The good news: every one of these mistakes has a clear symptom and a quick fix.

The Wet E7018 Rod: The Most Expensive Mistake on This List

Low-hydrogen coverings are thirsty. Leave E7018 rods out overnight, in a damp shop, or in a plain cardboard box, and the coating absorbs moisture. That moisture drives up diffusible hydrogen in the weld pool, which shows up later as porosity, and in stressed joints as hydrogen-induced cracking that may not appear for hours after you’ve finished welding.

The fix is storage discipline: keep opened low-hydrogen electrodes in a heated quiver or rod oven, and bake overheated or exposed rods following the manufacturer’s instructions rather than guessing at times and temperatures. If you’re unsure what a rod’s covering needs, the safety data sheet explains it. Under OSHA’s hazard communication rule, employers must make SDS documents available and train workers on the hazardous materials found in welding filler metals and fluxes (OSHA 1910.252).

Wrong Rod for the Joint, Wrong Polarity, Wrong Arc Length

E6013 is a wonderful rod for sheet metal, hobby work, and easy out-of-position beads. It is the wrong choice for a structural root pass that needs deep penetration. For that, reach for E6010 or E6011. Choosing by the numbers on the rod, not by habit, is exactly what the classification section of an arc welding electrode diagram is for.

Polarity matters just as much. Running a DC-only rod on AC, or swapping DCEP and DCEN without checking the chart, changes penetration depth and deposition rate almost immediately. And arc length is the classic beginner error: holding the rod too far from the work, or running the current too high or too low, are common causes of spatter, undercut and slag inclusions that electrode diagrams and manufacturer data help avoid (OSHA welding hazards guidance). Keep the arc roughly one electrode diameter long, and match the diameter to the joint: a 1/8 in. rod in a tight fillet will bridge and wash out; a 3/32 in. rod on thick plate will never keep up.

Starting the Arc and Holding the Rod

Striking an arc like a match grinds flux off the tip and contaminates the start. Scratch starting, like striking a match, is acceptable on plate, but on critical work use the tap method: touch and lift cleanly. And grip the electrode in the bare end shown on the diagram. Clamp onto the flux covering and you’ll crush it, crack it, and create a weak point where the coating burns unevenly. For more on all-position rod handling and technique, see our all position welding rod guide.

Symptom → Cause → Fix

Symptom	Likely cause	Fix
Porosity in E7018 welds	Moisture-pickup on covering	Store in heated quiver; bake per manufacturer instructions
Cracking hours after welding	Excess diffusible hydrogen	Switch to properly stored low-hydrogen rod; verify D1.1 requirements
Root pass won’t penetrate	E6013 used where E6010 needed	Select cellulose rod for deep penetration
Excessive spatter, undercut	Wrong polarity or current	Check fourth digit and manufacturer current range
Slag inclusions	Arc too long, travel too fast	Shorten arc; slow down; clean between passes
Coating cracks or falls off	Holder clamped on the covering	Grip only the bare contact end

Read the diagram once, and most of these failures never happen.

Conclusion: From Diagram to Confident Welds

The goal of every electrode diagram is the same: to turn guesswork into judgment. The cross-section diagram shows you exactly what a stick electrode is, from its bare steel core wire to its flux covering, grip end, measured diameter, and the way that covering burns back as you weld. The arc circuit diagram expands on that by placing the rod within the full system: the power source, electrode holder, cables, work clamp, arc, weld pool, slag layer, base metal, and the heat-affected zone. Together, these two drawings explain why no two rods can be treated as interchangeable.

All of this is tied together by the classification code. Once you know how to decode E7018 digit by digit, the stamp on the rod reveals its minimum tensile strength, the positions it can weld, its coating family, and the currents it is meant to run on. This shared language only works because it is enforced. Any carbon steel electrode must meet the requirements set out in AWS A5.1. An E6013 will never become a structural rod, and a low-hydrogen E7018 will never behave like a cellulose E6010, no matter how you hold it.

The Three Principles Worth Keeping

• The covering is the technology. Each coating family has a purpose. Cellulose promotes deep penetration, rutile offers a smooth and beginner-friendly arc, iron powder increases deposition, and low-hydrogen coatings are designed to limit hydrogen in the weld metal to help prevent cracking. If you know the coating family, you already have a solid idea of how the rod will behave before you strike an arc.
• Match before you burn. Your base metal, thickness, welding position, and available current should decide your electrode, not convenience. A root pass that needs deep penetration may call for E6010 or E6011, while sheet metal is often better suited to E6013. For a side-by-side breakdown of these options, see our All Position Welding Rod Guide.
• Safety is part of the diagram. The fume plume, UV output, and hydrogen content of a flux coating are all factors accounted for in electrode use. The OSHA welding standard 1910.252 ties that use to fire prevention, PPE, ventilation, and confined-space controls for every arc welding task.

Your Shop-Floor Action Checklist

Action	Why it matters
Memorize the E7018 digit meanings	Strength, position, coating, and current are all encoded in the number stamped on the rod.
Keep a labeled cross-section sketch nearby	A quick reference for core wire, covering, grip end, and diameter trains judgment faster than memorization alone.
Match the electrode to the joint first	Most bad welds start with a rod chosen for convenience rather than the base metal and position.
Store low-hydrogen rods properly	Moisture in E7018 or E7028 can lead to porosity and hydrogen cracking, so a heated quiver or oven is necessary.
Verify ventilation and PPE before each job	Helmet, screens, exhaust placement, and fire watch are non-negotiable per OSHA’s welding and cutting guidance.
Consult AWS A5.1 and D1.1 for code work	For structural steel, AWS D1.1 specifies which classifications are acceptable and what documentation must follow the weld.

For code work, the electrode choice is no longer a preference, but a documented requirement. Knowing why a classification is specified is what separates a technician from a button-pusher. The same diagram-first reasoning applies when evaluating Alloy Steel Welding Electrodes or expanding into other processes.

Reading Diagrams Builds Lasting Judgment

Diagrams may seem like beginner material, but the habit they build lasts an entire career. A welder who reads a cross-section before striking an arc, checks polarity, and understands what their flux is doing will catch mistakes before they become costly ones. Learn one classification completely, test it on scrap, and compare the result to what the code promised. Do this consistently, and the confusion in the welding aisle will disappear for good. The day you pick up a rod, read its code, understand its coating, and know what it will do before the arc strikes is the day the diagram finally becomes judgment. For those looking to formalize that skill, a structured Aluminium Welding Course is a practical next step.

Frequently Asked Questions

What does the diagram of an arc welding electrode show?

It shows the bare contact end held in the electrode holder, the extruded flux covering, the steel core wire inside, and the arc end where the covering burns back to create gas, slag and filler metal. It also shows the printed classification code and dimensions.

What do the numbers on E7018 mean?

E stands for electrode, 70 means a minimum tensile strength of 70,000 psi, 1 means the electrode works in all welding positions, and 8 indicates a low-hydrogen iron-powder coating usable on AC or DC. Similar logic applies to E6013, E6011 and other AWS classifications.

What is the difference between the core wire and the flux coating?

The core wire is the filler metal that becomes part of the weld, while the flux coating shields the arc from air, stabilizes it, forms protective slag, and can add alloying elements. Both are consumed as the electrode burns.

Why is E7018 called a low-hydrogen electrode?

Its covering is formulated to limit the moisture and hydrogen it introduces into the weld pool, which reduces the risk of porosity and hydrogen-induced cracking. Because it absorbs moisture from air, it must be stored properly, often in heated quivers or ovens.

Which electrodes are best for beginners?

E6013 rutile electrodes are forgiving, run smoothly on AC or DC, and produce clean-looking welds on thin material. E6010 and E6011 give deeper penetration for dirty or rusty metal and root passes, while E7018 is the standard for stronger structural joints.

What ventilation does OSHA require for arc welding?

Mechanical ventilation is required when welding in spaces under 10,000 cubic feet per welder, rooms with ceilings under 16 feet, or confined spaces, at a minimum of 2,000 cubic feet per minute per welder unless local exhaust or approved respirators are used. Local exhaust hoods must be kept close to the arc.

What filter lens shade does arc welding need?

OSHA’s guide recommends shade 10 for shielded metal arc welding with 1/16 through 5/32 in. electrodes, shade 12 for 3/16 through 1/4 in. electrodes, and shade 14 for 5/16 through 3/8 in. electrodes. Helmets or hand shields are required during all arc welding operations.

Why does my E7018 electrode produce porosity?

The most common cause is moisture absorbed by the low-hydrogen covering, along with paint, rust, oil or grease on the base metal. Use fresh, properly stored or rebaked rods and clean the joint before welding.