Stick Welding Diagram Guide: Symbols, Setup, Polarity & Electrode Selection (AWS Explained)

Imagine you’re staring at a fabrication drawing with cryptic lines, arrows, and letters next to a joint, with no idea how to make the weld. For stick welders, reading those diagrams is just as important as striking an arc to avoid costly mistakes and failed inspections.

Introduction: Why Stick Welding Diagrams Matter

A welder once told me the story of a structural repair that cost his crew a full weekend and several hundred dollars in consumables. The drawing called for a 5/16 inch fillet weld on one side of a T-joint. He read the symbol upside down, welded both sides at 3/8 inch, and the inspector rejected the work. Nothing about his arc control or hand speed was wrong. He simply misread the diagram.

That is the quiet reality of stick welding on real jobs. Shielded metal arc welding (SMAW) is still one of the most trusted processes in the world precisely because it is portable, forgiving, and capable of producing sound welds in the field, on a hillside, inside a boiler, or on a ladder. But the arc is only half the job. The other half is understanding what the drawing is actually asking you to do.

Where Stick Welding Diagrams Show Up in Real Work

Consider where SMAW is used every day:

• Structural construction: beams, columns, base plates, and connection details are all specified with weld symbols on the fabrication drawing before a single rod is struck.
• Pipe and pressure work: root passes, fill, and cap are dictated by joint prep details, bevel angles, root openings, and pass counts shown right on the print.
• Field repairs and maintenance: broken brackets, worn equipment, and cracked frames get fixed with a stick welder because, as covered in Advantages of Stick Welding: Why SMAW Still Wins, the process travels well and tolerates dirt, wind, and imperfect fit-up better than most alternatives.
• Heavy equipment and alloy work: even when the base metal is specialized, the drawing still communicates size, length, and contour through the same symbol language.

In each case, the diagram is the contract between the engineer and the welder. It tells you which joint, which side, what size, how long, whether it is field-welded or shop-welded, and what finish is expected. Guessing at any of those details is how projects end up with over-welded joints that waste filler metal and introduce distortion, or under-welded joints that fail load calculations and inspection.

How Misreading a Diagram Becomes a Defect

Most weld defects traced back to “operator error” really begin at the drawing stage. Common chain reactions include:

1. Ignoring the root opening called out on the print, then burning through or leaving lack of fusion.
2. Mistaking the arrow side for the other side, placing a fillet weld where it carries no load.
3. Welding past a length dimension, creating residual stress and distortion in a restrained assembly.
4. Missing a contour or finish symbol, then grinding or leaving a reinforcement the code does not allow.

Under-welding risks structural failure; over-welding burns money, warps plate, and can actually reduce fatigue life. On code work, both outcomes are equally unacceptable.

The Standard Behind the Symbols: AWS A2.4

You do not have to memorize every symbol on instinct. In North America, welding symbols are governed by a single reference document: AWS A2.4, Standard Symbols for Welding, Brazing, and Nondestructive Examination. It defines the anatomy of the welding symbol, the meaning of each weld type, and how dimensions, tails, arrows, and supplementary symbols combine. The American Welding Society publishes a handy AWS Weld Symbol chart that many welders tape inside a tool box lid for quick reference.

The current edition is AWS A2.4:2020, and it introduced a meaningful update to how some symbols are presented, as explained by the ANSI Blog overview of the A2.4-2020 changes. If you learned your symbols from an older handbook or an on-the-job shortcut, it is worth confirming your habits against the current standard, since shop drawings you receive may follow either version.

One important boundary: A2.4 tells you how a weld is specified, but it does not tell you how to make it. The procedure details, such as amperage, electrode choice, preheat, and travel speed, live in a Welding Procedure Specification (WPS). Reading the diagram and following the WPS are two separate obligations, and code jobs require both.

That distinction shapes the rest of this guide. Over the next sections we will build the full picture: the electrical circuit and polarity behind every stick arc, the anatomy of an AWS symbol read line by line, electrode selection, joint preparation, techniques matched to weld sizes, troubleshooting when things go wrong, and finally several realistic drawing walk-throughs you can follow along with.

Stick welding rewards people who read as carefully as they strike. Learn the diagram language once, and every drawing after that becomes an instruction instead of a puzzle.

Stick Welding Basics: Circuit, Polarity, and Setup

Every stick welding diagram you read assumes a machine set up correctly and an operator who knows where the current is actually going. Reverse a polarity and you can follow the drawing perfectly and still end up with a cold, underfilled weld. Before symbols and joints, get the circuit right.

The Stick Welding Circuit

Shielded metal arc welding is a closed loop. Current leaves the power source, travels through the electrode cable to the holder, crosses the arc into the workpiece, and returns through the work clamp and cable back to the source. Break any link and the arc simply will not strike.

The electrode is part of that loop, which is why arc length, cable condition, and clamp placement show up later as arc stability complaints. A loose work clamp forces current through a poor path, the machine responds unpredictably, and the result looks like an amperage problem when it is really a circuit problem.

Conventional current flows from positive to negative through the external circuit while electrons travel the opposite way. That distinction matters because the two terminals behave very differently at the arc.

DC vs AC: Why Constant Current Rules

Stick machines come in DC, AC, and DC/AC versions, and all of them share one design requirement. Constant current (CC) power sources are the standard for SMAW because they hold amperage steady while arc voltage fluctuates. Shorten or lengthen the arc and voltage swings, but current barely moves, so heat input stays predictable.

A constant voltage (CV) machine, the kind used for MIG, would be a poor stick welder: small changes in arc length would cause violent current spikes and burn the rod. This is also why stick amps are set as a target rather than a ceiling, and why hand control still matters. AC earns its place on simple site generators and reduces magnetic arc blow, the sideways deflection that appears when DC current turns a corner through the joint.

Polarity: DCEP vs DCEN

Polarity is simply which terminal the electrode sits on. It changes where the heat goes, and therefore the penetration profile you get from the same rod at the same amperage.

Factor	DCEP (reverse polarity)	DCEN (straight polarity)
Electrode connected to	Positive terminal	Negative terminal
Heat distribution	Roughly two thirds at the electrode end	Roughly two thirds at the workpiece
Penetration	Deep and narrow	Shallower and wider
Typical use	Root passes, pipe, vertical and overhead, open roots	Fast travel on flat fillets, thin sheet, cover passes
Common rods	E6010, E7018	E6013, E7014

E6010 typically runs best on DCEP for deep penetration, which is why it is the classic root rod for open-root pipe and structural passes that must fuse through the full joint. Run the same rod on DCEN and you get a floating, shallow bead that reads as lack of fusion on a radiograph.

Equipment Setup Before the Arc

Basic setup for a stick job follows a repeatable order:

• Inspect cables and holder for cracks, exposed copper, and heat damage before powering on.
• Set polarity to match the electrode classification printed on the rod wrapper.
• Dial amperage from rod diameter and plate thickness. Miller’s electrode selection guidance recommends starting mid-range, then adjusting by bead appearance.
• Attach a clean work clamp to bare metal as close to the joint as practical.
• Position for the joint shown on the drawing, with a fire-safe area and clear ventilation.
• Match electrode diameter to the weld size called out; a 1/8 in rod cannot make a clean 3 mm fillet in a tight corner.

Arc length should stay roughly equal to the electrode core wire diameter. Longer arcs lose shielding, wander, and introduce porosity before you have laid a full bead. A steady crackle tells you amperage and arc length are both right.

PPE and Safety Essentials

Stick welding throws intense ultraviolet light, molten spatter, and fume. Minimum protection is an auto-darkening helmet or a fixed shade lens matched to your amperage, a flame-resistant jacket and sleeves, heavy leather gloves, safety glasses under the helmet, hearing protection, and boots. Industry safety training materials also stress respiratory protection and forced ventilation, especially indoors.

Position work so the arc never faces unprotected people, clear combustibles from the hot zone, and never weld on sealed containers without clearance.

Understanding AWS Weld Symbols and the Stick Welding Diagram

A stick welding diagram carries two layers of information on one print: the drawn joint, with its bevels, root openings, and plate edges, and the symbols that tell you what kind of weld to place in it. AWS A2.4, the standard for welding, brazing, and nondestructive examination symbols, clears up most beginner confusion with one distinction. A weld symbol is the small glyph by itself, identifying the type and geometry of the weld: fillet, square groove, V-groove, bevel, plug, spot, and so on. A welding symbol is the complete assembly of reference line, arrow, weld symbol, dimensions, and an optional tail, and it tells you where that weld belongs and how much of it to run. Reading the glyph without its line is like reading a dimension number without knowing which feature it belongs to.

Anatomy of a Welding Symbol

Every welding symbol on a fabrication drawing is built from the same five parts, and each answers a specific question:

• Reference line. The horizontal backbone of the symbol. Everything is positioned relative to this line, and its two sides carry the single most important rule in symbol reading, covered below.
• Arrow. A leader line with a pointed end that touches the joint you are welding. On bevel and J-groove joints the arrow often has a break in it, which points specifically at the member that must be beveled or grooved.
• Weld symbol. The glyph sitting on the reference line. A right triangle means fillet, parallel lines mean square groove, a single slanted line means bevel, paired slanted lines mean V-groove, and a circle means plug or spot.
• Dimensions. Numbers to the left of the weld symbol give the weld size, such as fillet leg length or groove depth. Numbers to the right give the length, or the pitch when welds are intermittent. If no length is shown, the weld runs continuously along the whole joint.
• Tail. The forked or V-shaped element at the back of the reference line, used only when something extra needs saying: a welding process, a specification, a procedure number, or a quality class. If the tail is absent, no special reference applies.

Around that frame sit the supplementary marks. A circle at the junction of arrow and reference line means weld all around the part. A small flag means a field weld, made on site rather than in the shop. A straight, arched, or angled line across the tip of the weld symbol describes the finished contour as flush, convex, or concave, and a letter beside it can call for the finishing method, such as G for grinding or M for machining. Keep the full set on hand as a reference sheet; AWS publishes an official welding symbol chart you can print and post above your bench.

Arrow Side vs. Other Side

This one rule resolves most misreads. If the weld symbol sits below the reference line, the weld goes on the arrow side, meaning the exact side of the joint the arrow is touching. If it sits above the reference line, the weld goes on the other side, the opposite face of the same joint. A fillet symbol below the line on a T-joint means weld the leg your arrow points at, nothing more; the same symbol above the line means weld only the far leg. When the designer wants welds on both sides, symbols appear above and below the line at once, and shared dimensions are written between them. Build the habit of following the arrow to the joint first, then checking the line, then reading the glyph. Welders who read the glyph first routinely put a fillet on the wrong face of a double-fillet joint, and on a symmetric T-joint nobody notices until fit-up or inspection does.

From Drawing to Joint: Reading a Stick Welding Diagram

Working from print to arc is a repeatable sequence:

1. Locate the arrow and confirm it lands on the joint you think it does, especially where several joints cluster together.
2. Check which side of the reference line the weld symbol occupies, and translate that into arrow side or other side on the real part.
3. Identify the glyph to learn the weld type, then read size on the left and length or pitch on the right.
4. Look at the joint detail for geometry the symbol does not carry: bevel angle, root opening, root face, backing bar, or whether the joint is open root.
5. Check for supplementary marks such as the field-weld flag, the all-around circle, or a contour and finish requirement.
6. Open the tail, if present, for the process or procedure reference, then confirm electrode and polarity against the WPS or your own all-position welding rod selection before cutting and tacking.

Do that consistently and a stick welding diagram stops being cryptic line work. The symbols are deliberately logical: one line, one arrow, one glyph, a few numbers. Since standards evolve, and AWS A2.4 has been revised across editions including the 2007 and 2020 versions, confirm current conventions against the summary of changes to AWS A2.4-2020 before interpreting a recent drawing rather than relying on a chart you memorized years ago. Master the reading first and the rest of the process, from why stick welding still wins on site to the final pass, follows the print instead of fighting it.

Electrode Selection for Stick Welding

A stick welding diagram can hand you the joint type, the weld size, and the number of passes, but it cannot put metal in the puddle. The rod you load into the stinger is the final decision before the arc, and it decides whether the finished weld actually performs what the drawing called for. Use a fast-freeze rod where the symbol asked for a soft capped fillet, or drag a rutile rod through a greasy root, and the bead will look acceptable right up until the inspector’s hammer comes out.

Reading the Number: What E7018 Actually Means

Every stick electrode carries an AWS classification that is really a specification written in shorthand. Take E7018 apart:

• E means electrode for arc welding.
• First two digits (70) give the minimum tensile strength of the deposited weld metal in thousands of pounds per square inch. Seventy means 70,000 psi; an E6010 is 60,000 psi.
• Third digit (1) is the welding position. A 1 means all positions: flat, horizontal, vertical, and overhead. A 2 means flat and horizontal fillet work only.
• Fourth digit (8) identifies the coating type and the current the rod is designed for: AC, DCEP, DCEN, or a combination.

Lincoln Electric’s AWS classification breakdown spells out each digit, while Miller’s guide to factors for selecting the right stick electrode adds the variables the number alone will not tell you: base metal thickness, joint geometry, position, machine output, and service conditions.

Coating Chemistry: Cellulosic, Rutile, or Low Hydrogen

The flux does far more than shield the arc. It sets penetration depth, bead shape, slag behavior, and how forgiving the rod is when your hand gets tired.

• Cellulosic coatings (E6010, E6011) contain organic material that burns into a deep, forceful arc. Excellent for root passes and dirty plate, but smoky and spattery.
• Rutile or titania coatings (E6013, E7014) deliver a smooth, quiet arc with easy starts and a flat profile. These are the friendly rods, and E7014’s iron powder content lets you stack deposit quickly.
• Low-hydrogen coatings (E7018) are lime-based and keep hydrogen out of the puddle, which is exactly why structural and pressure work specifies them.

The Five Rods You Will Actually Use

Electrode	Coating	Polarity	Penetration	Positions	Best for
E6010	Cellulosic	DCEP only	Deep, forceful	All	Root passes, pipe, vertical uphill, dirty or scaled steel
E6011	Cellulosic	AC or DC	Deep, forceful	All	Field repairs on AC machines, farm work, rusty plate
E6013	Rutile	AC or DC	Soft, shallow	All (best flat/horizontal)	Thin sheet, cosmetic caps, learning arc control
E7014	Rutile + iron powder	AC or DC	Medium	All (best flat/horizontal)	Fast fill on mild steel, production fillets
E7018	Low hydrogen + iron powder	AC or DC	Medium, smooth	All	Structural steel, anything inspected or load-bearing

Hydrogen Control and Rod Storage

Low-hydrogen rods can carry an optional suffix: H4, H8, or H16, which is the maximum millilitres of diffusible hydrogen per 100 grams of deposited metal. H4 means 4 mL, the tightest common rating, and the one critical work usually demands. Hydrogen is the ingredient behind cold cracking in restrained joints, so a fresh E7018 sitting in an open box on a humid job site slowly loses the very property you bought it for. Keep rods in a sealed quiver, and re-bake them at the manufacturer’s temperature and time schedule when they have been exposed. Old, popped rods are cheap to replace and expensive to defend in a failed inspection.

Matching the Rod to the Base Metal

The rule of thumb is to match or slightly exceed the base metal’s tensile strength. A36 structural plate pairs naturally with E7018 or E7014 because both deliver around 70,000 psi. Going far above base metal strength is not automatically better: on very high-strength steels, an overmatched, hard weld can crack as it cools. Thin sheet calls for the opposite adjustment, since a deep-penetration E6010 at high amperage will blow through, where a soft E6013 at the bottom of its range will not. Once the base metal is an alloy rather than plain carbon, coating and chemistry start to matter more than convenience, so review Alloy Steel Welding Electrodes: Selection, Use & Safety before guessing.

Finally, the drawing wins. If the job has a welding procedure specification, its electrode classification, polarity, amperage, and preheat requirements override any general rule you read here. When there is no WPS, start from the classification on the drawing, verify the coating suits the position and the machine, and make a test bead on scrap of the same thickness before committing to the joint.

Joint Preparation, Fit-Up, and Reading Diagrams for Each Joint

Most stick welds are won or lost before the first arc is struck. A stick welding diagram rarely describes the finished bead alone; it describes the joint that has to exist first: how far the pieces sit apart, what angle they are beveled to, whether a backing strip goes in, and how many passes the joint can realistically hold. Get that preparation right and a simple 7018 runs like it is on rails. Get it wrong and no amount of hand skill rescues the root.

The conventions you are reading come from one place: AWS A2.4, Standard Symbols for Welding, Brazing, and Nondestructive Examination. When a drawing calls out a groove type, root opening, or backing detail, that requirement is expressed through the symbol set cataloged in the AWS weld symbol chart, and it carries the same authority as a written note.

The Five Basic Joints and What the Diagram Asks For

Every stick welding diagram you will ever face is built from five joint configurations. Recognizing which one you are looking at instantly narrows down the prep and the electrode.

Joint	How the pieces sit	Typical diagram requirement
Butt	Two edges aligned in the same plane	Groove symbol (V, bevel, U, or square), root opening, sometimes backing
T-joint	One member perpendicular against the face of another	Fillet symbol, often both sides, size given as leg length
Lap	One plate overlaps the other	Fillet symbol on each exposed edge of the overlap
Corner	Edges meet at an angle to form a corner	Fillet, partial groove, or full groove depending on load
Edge	Ends of two (or more) parallel plates flush	Edge groove symbol with weld size equal to plate thickness

Root Opening, Bevels, and Backing: The Three Variables

Root opening is the gap between the two members at the joint root. It exists so the arc can reach the bottom of the joint instead of sitting on top of it. Open-root pipe joints and structural butt joints both depend on it, and the drawing usually states the gap directly or shows it on a detail view.

Bevels and land control access. A single-V, double-V, or J-groove needs far less filler than a square groove on thick plate, and the included angle plus a small flat (the land) at the root keeps the first pass from blowing through. Common structural bevels sit around 30 to 37.5 degrees per side, but the drawing or the governing WPS always wins over a shop rule of thumb.

Backing is a strip, ring, or consumable insert welded or placed behind the root to support the first pass. AWS gives backing its own symbol, so a drawing can call for it without a paragraph of text. It is not optional shop improvisation: backing is used per the WPS and the symbol, because it changes penetration, chemistry, and sometimes the required inspection. A sample WPS form shows how joint details, backing, and passes are documented alongside the symbol.

Fit-Up Tolerances: Why a Few Millimeters Change the Whole Weld

Fit-up tolerance directly sets penetration and pass count. A root that is slightly too tight starves the root face of heat and leaves lack of fusion or incomplete penetration; a gap that is too wide risks burn-through, sagging, and an extra fill pass you did not budget for. High-low misalignment forces you to chase the land with the rod, which almost always leaves undercut on the thick side.

• Gap too small: insufficient penetration, higher amperage needed, higher risk of lack of fusion.
• Gap too wide: excess consumption, bead sag, possible burn-through on thin plate, more passes.
• Excess bevel angle: wider weld volume, more electrodes, more distortion.
• Dirty or mill-scaled root: porosity and slag inclusions that no technique fix will remove.

When fit-up is out of tolerance, correct it rather than compensating with current. Air-arc gouging and carbon arc cutting is the standard way to open a root, clean a bad first pass, or re-establish a bevel before rewelding.

From Symbol to Joint: Reading Prep in Four Steps

1. Find the arrow and identify the joint type. The arrow points at the member to be prepared; the joint geometry tells you butt, T, lap, corner, or edge.
2. Read the groove symbol on the correct side. Symbol below the reference line means arrow side; above means other side. A V with a bevel angle and depth note tells you exactly what to cut.
3. Check for root opening, backing, contour, and finish marks in the detail view or the symbol’s supplemental letters, and note anything the tail references, such as a WPS number or code.
4. Translate to a physical checklist: gap gauge, bevel gauge, grind marks removed, tacks placed and cracked open where required, plates aligned within tolerance.

Then pick the electrode to suit the joint you actually have. Open-root passes almost always call for a fast-freeze rod such as E6010 or E6011 with a whip-and-pause motion, because they punch through the gap and tie into both root faces cleanly. Fill and cap passes on a prepared groove move to a fill-freeze or low-hydrogen rod like E7014 or E7018, in the positions the all-position welding rod guide matches to your joint orientation.

This is also where stick welding earns its reputation for field tolerance: a beat-up fit-up, a windy jobsite, and a rusty plate are conditions SMAW handles better than most processes, one of the core advantages of stick welding. The diagram still sets the standard; the process simply gives you the tools to meet it.

Stick Welding Techniques Mapped to Diagrams

A weld symbol tells you what the weld should be: a fillet with a 6 mm leg on the arrow side, a groove weld with a specific bevel, a 150 mm long weld with a 50 mm gap. It never tells you how to move the rod. That translation, from symbol to hand motion, is where welders earn their keep or grind out rework. Here are the core SMAW techniques, mapped back to what a stick welding diagram actually calls for.

Stringer Beads: The Code Worker’s Default

A stringer is a straight, no-weave bead pulled along the joint at a steady travel speed. For code work, stringers are the preferred technique because they put less heat into any single spot, produce a flatter, more uniform profile, and give the welder far better control over penetration and overlap.

When a drawing calls for a small fillet, say 5 mm or 6 mm legs on a T-joint, a single stringer pass is usually the right answer. Weaving a small fillet almost guarantees an overstuffed profile that fails visual inspection. Rule of thumb: if the required size fits within roughly one electrode diameter of throat thickness, run it stringer, single pass.

Stringers also drive multi-pass work. On a thick groove weld, the root, hot, fill, and cap passes are each built from stacked stringers, overlapped by about half the bead width, with a work angle of 5 to 15 degrees depending on position. For a broader look at rod behavior in these situations, our All Position Welding Rod Guide covers which electrodes hold up best when you are not welding flat.

Weaving: Bigger Deposition, Bigger Responsibility

A weave moves the electrode side to side, depositing more metal per pass and helping tie into both sides of a wide joint. It is how you fill a wide V-groove cap without twenty stringers. But weaving adds heat, widens the heat-affected zone, and lingering too long at the toes invites undercut.

Match weave width to the rod. A common field rule is no wider than two to two-and-a-half electrode core diameters, so a 3.2 mm rod has no business crossing a 25 mm gap. On a cap pass calling for a flush or slightly reinforced profile, a controlled weave with a brief pause at each toe gives you even edges. On thin sheet, forget the weave entirely.

Whip and Pause: The Vertical-Up Workhorse

Whip and pause means driving the arc forward about an electrode diameter, backing off to let the puddle solidify, then repeating. It is the classic vertical-up technique for fast-freeze rods like E6010 and E6011, because it forces the puddle to freeze before gravity drags it down the plate.

Vertical-up with a slow-freeze rod like E7018 is a different animal: a tight arc, small controlled weaves, and constant attention to puddle width. Technique choice often comes straight from the electrode’s AWS classification, and our breakdown of alloy steel welding electrodes shows how coating and classification shape manipulation style across alloy families too.

Multi-Pass: Following the Size the Symbol Calls For

Most weld symbols carry a size dimension, and that number drives the entire technique plan. Fillet size equals leg length; groove symbols translate into required throat and total fill. Once you calculate the required metal volume, you can plan pass count realistically. A 12 mm butt joint with a 60-degree V, 3 mm root opening, and no backing needs roughly three to four passes: root, hot, one or two fills, and a cap. Widen the root or add a backing strip and the fill volume climbs fast. The diagram gave you all the numbers; your job is turning them into a sequence that keeps heat input reasonable.

Interpass Temperature: The Low-Hydrogen Discipline

Every pass you run preheats the metal ahead of the next one. With low-hydrogen electrodes like E7018, exceeding interpass temperature is a real cracking risk, especially on restrained joints and alloy steels. Welding codes set maximum interpass limits, and a quality WPS states them explicitly alongside preheat requirements, in line with AWS symbol and procedure documentation standards (AWS A2.4, AWS weld symbol chart).

Practically, this means planning your pass sequence before you strike the first arc. Alternate positions on long seams, check temperature with a thermometer rather than a guess, and re-bake E7018 rods that have been sitting out. Interpass control is invisible on the drawing but decisive in the finished weld.

Technique-to-Symbol Checklist

• Small fillet, single pass: stringer bead, correct all-position rod.
• Large fillet, multi-pass: stacked stringers or narrow weaves, watch leg size.
• Wide groove cap: weave width limited to two electrode diameters, pause at the toes to avoid undercut.
• Vertical-up with a fast-freeze rod: whip and pause, tight arc.
• Low-hydrogen requirement: plan passes, monitor interpass temperature, keep rods in the oven.

None of this replaces the WPS. When a procedure specification exists, it outranks field habit every time and will define technique constraints, amperage ranges, and pass sequencing more precisely than any symbol could. But working from a drawing alone, mapping size and position to stringer, weave, or whip is the skill that separates a weld that passes from one you have to cut out.

Common Mistakes, Defects, and Troubleshooting with Diagrams in Mind

Here’s the uncomfortable truth about weld defects: most are decided before the arc is struck. A welder who misreads the symbol, skips the called-for root opening, grabs the wrong rod, or sets the wrong polarity produces a defect no hand skill can repair. Inspection doesn’t just expose poor technique, it exposes poor interpretation. When a bead comes back flagged, the first question worth asking is not “what did my hands do?” but “what did the drawing ask for, and did I actually give it that?”

Porosity: Trapped Gas Starts on the Drawing

Porosity shows up as pinholes, worm tracks, or a sponge-like surface. The usual suspects are well known: oil, paint, rust, and mill scale on the joint; an arc that’s too long; a work clamp on a dirty surface; or travel fast enough to freeze the puddle before gas escapes. Diagram reading matters here through preparation and process choice. If the symbol calls for the joint to be cleaned to bright metal, or specifies a low-hydrogen electrode for a load-bearing connection, ignoring that call invites porosity and worse. Moisture is the hidden driver: low-hydrogen (E7018) electrodes pick up moisture from shop air, and manufacturers expect them stored in a rod oven or rebaked per their instructions before use.

Lack of Fusion and Lack of Penetration

Lack of fusion is a cold, unbonded line between weld and base metal; lack of penetration is a root that never tied through. Both trace back to setup: amperage too low, an electrode that freezes too fast for the joint, an arc held too far out, or a weave so wide the puddle never reaches the toes. Diagram errors cause them just as often, by skipping the specified bevel angle, ignoring the root opening, or leaving out the backing strip the detail clearly shows. An AWS weld symbol chart tells you exactly what groove depth, root face, and weld size were engineered for the load. When a joint needs deep root bite, rods like E6010 and E6011 are the go-to choices, and you can compare their behavior in our All Position Welding Rod Guide: Types, Uses & Tips.

Undercut: Speed, Amperage, and Arc Length

Undercut is that groove melted into the base metal alongside the toe of the weld. It almost always comes from excessive travel speed or amperage, a long arc, or a weave that pauses too briefly at the edges in vertical and overhead positions. The diagram angle: when the symbol calls for a 1/4 in fillet and the welder pushes a hot, fast bead just to reach that size quickly, the edges get gouged. Slow down, shorten the arc, and let the puddle wash into the sidewall instead of cutting it.

Slag Inclusions: Clean Between Passes

Slag gets trapped when a new bead is laid over an incompletely cleaned previous pass. It’s common in multi-pass fillet welds, lap joints, and any groove where the detail shows more than one pass. Fast-freeze rods such as E6013 leave a heavy slag that must be chipped and wire-brushed fully. If the drawing shows a multi-pass or all-around fillet, budget cleaning time into the sequence instead of treating it as an afterthought.

Cracking: Moisture, Restraint, and Mismatched Metal

Hydrogen-induced cracking is the defect with the longest fuse: it can appear hours after welding. Moisture in low-hydrogen electrodes is the primary cause, along with high restraint, a hard heat-affected zone, and filler metal stronger than the base metal. The fix is procedural: dry rods, appropriate preheat and interpass temperature, and filler that matches or slightly undermatches the base metal. For tricky base metals, our Alloy Steel Welding Electrodes: Selection, Use & Safety guide walks through matching classifications to the material on the drawing. Any time the detail references a written procedure, that procedure overrides general shop advice, as the sample AWS WPS sample form makes clear.

Stick Welding Troubleshooting Matrix

Defect	Usual cause	Diagram/setup link	Fix
Porosity	Dirty joint, moisture, long arc	Cleaning note ignored	Clean to bright metal; dry stored rods; shorten arc
Lack of fusion	Low amperage, wide weave	Wrong electrode for joint type	Raise amperage; stringer beads; verify class
Lack of penetration	No root opening, no bevel, cold settings	Bevel/root detail skipped	Restore fit-up; deep-penetration rod (E6010/E6011)
Undercut	Fast travel, high amps, long arc	Weld size chased too aggressively	Slow down; reduce amps; pause at toes
Slag inclusion	Uncleaned pass, heavy slag	Multi-pass weld under-sequenced	Chip and brush between passes
Cracking	Moisture, restraint, mismatched filler	Wrong class or skipped preheat	Rebake rods; preheat; match filler to base metal
Arc instability	Wrong polarity, bad ground	Polarity not set per electrode	Check DCEP/DCEN against the rod’s specification

Wrong polarity deserves special mention because it sabotages everything else: it causes an unstable, sputtering arc and poor penetration, which later shows up as lack of fusion or porosity. Set DCEP or DCEN exactly as the electrode classification requires before you blame your hands.

Work the matrix in reverse order when something goes wrong. Confirm polarity, then amperage and arc length, then electrode class against the symbol, then joint preparation against the detail, and only then adjust technique. That sequence turns a failed inspection into a five-minute correction instead of a full day of rework.

Practical Examples: Reading Real Stick Welding Diagrams

Weld symbols only start making sense when you run them against a real joint. Three drawings show up constantly in fabrication shops and on pipe crews: a fillet-welded T-joint, a bevel groove with a backing bar, and an open-root pipe weld. Each walkthrough covers the same four things in order: what the symbol actually says, how the joint gets prepped, which rod and polarity go in the stinger, and the pass sequence that finishes the weld. If you are still shaky on symbol anatomy, the official AWS welding symbol chart is worth taping inside your toolbox lid.

Example 1: Fillet Weld on a Simple T-Joint

What the drawing says. The arrow touches the vertical plate where the bracket meets it. On the horizontal reference line sits a right triangle, the fillet weld symbol, drawn below the line. Placement is the whole game: a symbol below the line means arrow side, a symbol above means other side. One figure sits to the left of the triangle, giving the leg size: 1/4 in. The tail carries the process callout, usually “SMAW” or a WPS reference number, because the process may be called in the tail per WPS, as laid out in AWS A2.4.

How it runs. Clean about 2 in. of mill scale back from both edges, hold the plates square with a fixture or a couple of tacks, and check for a gap: this joint wants tight fit-up, not an open root. A 1/8 in. E7018 on DCEP around 110–130 A gives a quiet arc and a flat, slow-freezing puddle suited to 1/4 in. fillet legs. One stringer pass per side is enough at this size. Alternate sides between passes so the heat pulls the bracket straight instead of out of square.

The trap. New readers put the triangle above the line and weld the far side of the joint. If no contour or finish symbol is drawn, nobody is inspecting the profile for machining; they are checking leg size and fusion at the toes.

Example 2: Bevel Groove Butt Joint with a Backing Bar

What the drawing says. Here the symbol is a single-bevel groove (one vertical line, one angled line) below the reference line, with figures in front of it: the first number is the root opening, say 1/4 in., and the second is the groove angle, say 45°. Alongside sits the small rectangle of the backing symbol, calling for a strip welded on the arrow side. Groove details like these are exactly why a standard weld symbol reference matters: geometry, root, and backing all live in one compact cluster.

How it runs. On 3/8 in. plate, cut a 45° bevel, leave a 1/16 in. root face, and land the plates on a backing bar sized to cover the root. Strike the root with a 1/8 in. E6010 on DCEP: its deep-penetrating, fast-freezing arc burns through light contamination and stays controllable in an open gap. Follow with a hot pass, then fill and cap with E7018 in stringers, stacking beads bottom up and chipping and wire-wheeling between passes so no slag gets buried. Bury the root and you get the classic lack-of-fusion reject.

Example 3: Open-Root Pipe Weld (6G Position)

What the drawing says. The joint is a bevel groove on the arrow side with root opening and root face called out, and no backing rectangle, because pipe cannot be backed. That absence is the instruction: 100% root penetration is required from the inside face. A flag at the junction of the arrow and reference line would mean weld in place, and a note in the tail may identify the specific procedure, since the process may be called in the tail per WPS.

How it runs. On 6 in. schedule 40 carbon steel, cut a 30° bevel per side, leave a 1/16 in. land, and set a 3/32 in. root gap. A common crew sequence is an E6010 root on DCEP, a hot pass to smooth the root profile, then E7018 fill and cap from the 5G or 6G position, tying each stop-start in with a quick grind. Positionability matters as much as classification, which is why welders keep an all position welding rod guide handy, and if the drawing notes a low-alloy grade, the electrode choice shifts toward filler-matching consumables covered in alloy steel welding electrodes.

Example	Symbol features	Rod & polarity	Sequence
T-joint fillet	Triangle below reference line, 1/4 in. leg	E7018, DCEP	Tack, one stringer per side, alternate
Bevel with backing	Bevel symbol, root opening, backing rectangle	E6010 root, E7018 fill/cap, DCEP	Root, hot pass, fill, cap
Open-root pipe	Bevel, root face, no backing symbol	E6010 root, E7018 cap, DCEP	Root, hot, fill, cap in 6G

The pattern across all three is the same: the drawing gives geometry, size, and side; the WPS gives amps, technique, and travel direction. A handy sample WPS form shows how those two documents split the job, and the guidance in Miller’s stick electrode selection factors bridges them. Read the symbol first, confirm the procedure second, then strike the arc.

Tips, Resources, and Staying Code Compliant

Reading the diagram correctly gets you to the joint. Staying compliant is what keeps the weld in service. Whether you’re patching a trailer frame in your driveway or welding structural steel under inspection, the same habit separates a weld that passes from one that gets cut out: check the paperwork before you strike the arc.

Start With the WPS, Not the Drawing Alone

A welding drawing tells you what weld is required. A Welding Procedure Specification (WPS) tells you how to make it: process, electrode classification, polarity, amperage range, heat input limits, preheat, interpass temperature, and position. On code work, the WPS and the applicable standard always override general guidance like this article. If the drawing calls for a 3/16 fillet with E7018 and the WPS says 1/4 inch minimum, the WPS wins, and so does the inspector.

You don’t have to guess at WPS formatting. AWS publishes a free sample WPS form that shows every field a procedure needs, and training materials from education agencies walk through how qualification records tie back to the base metal and joint. If your shop has no WPS for a job you’ve been assigned, that’s a question for the supervisor, not a license to improvise.

Keep Your Symbols and Resources Within Reach

The single best investment for anyone reading stick welding diagrams is a printed copy of the AWS welding symbol chart. AWS maintains a free downloadable weld symbol chart that you can tape inside your toolbox lid. For the underlying standard, AWS A2.4 remains the reference for symbol interpretation, and the 2020 revision notes explain what changed for anyone working from an older drawing set. Keep the older A2.4 edition handy too, since legacy fabrication drawings still circulate widely.

For electrode data, Lincoln Electric’s AWS classification breakdown and Miller’s electrode selection factors are dependable free references, while voestalpine’s electrode selection guide covers matching consumables to alloyed and structural steels in more depth.

Shop Habits That Keep Diagrams Honest

• Store low-hydrogen rods in heated ovens per the manufacturer. E7018 and other low-hydrogen electrodes absorb moisture sitting in open air, and damp covering is a leading cause of porosity and hydrogen-induced cracking. Re-bake only within the manufacturer’s published time and temperature limits, and keep rods in a rod caddy between oven and workbench.
• Match amperage to electrode diameter and the WPS range. A quick reference chart gets you in the ballpark, but the correct setting depends on thickness, position, and polarity. Our all position welding rod guide covers which rods behave well out of position and where the current window narrows.
• Check fit-up before the first arc. Measure root opening, bevel angle, and land against the drawing dimensions. Gaps grow weld volume, gaps shrink penetration, and neither is a substitute for the joint the engineer specified.
• Verify polarity at the machine, not by memory. Confirm the holder connection matches the electrode requirement, especially if the machine was last used for a different process.
• Clean between passes. Chip and wire-brush slag before re-striking; trapped slag is one of the few defects that starts as a diagram-reading failure and ends as a rejected coupon.

If your work drifts toward other processes or materials, keep the same discipline. Related topics such as alloy 20 welding procedures and alloy steel welding electrodes show how quickly procedure requirements tighten once the base metal leaves plain carbon steel behind.

Where to Learn and Verify

Continuing education keeps symbol reading sharp. AWS publishes the standards themselves, while manufacturer technical libraries and accredited training programs translate them into shop practice. For a broader look at certification pathways and what inspectors actually look for, our piece on aerospace welding standards demonstrates how much stricter documentation becomes as the application gets more critical.

The rule of thumb is simple: understand the diagram with general knowledge, execute the weld under the governing WPS and code, and document everything you did. That’s how a symbol on paper becomes a weld that lasts. In the conclusion, we’ll pull the whole diagram-first approach together.

Conclusion: From Diagram to Dime-Worthy Weld

Every strong stick weld starts before the hood drops. It starts on paper, with a reference line, an arrow, a few letters, and a number that tells you exactly what the fabricator expects. Throughout this guide we have walked that path from drawing to arc, and the pattern holds every time: read first, set up second, strike arc last.

Here is the short version of everything we covered, compressed into the checklist worth taping inside your toolbox lid.

• The diagram is the contract. The arrow side and other side of the reference line decide which member gets the bevel, which joint gets the weld, and where the weld actually sits. Tail symbols, field weld flags, and contour or finish marks add instructions that no amount of experience can guess at.
• Polarity and electrode choice are not preferences. DCEP concentrates heat at the electrode for deeper penetration, DCEN pushes heat into the work with faster deposition, and AC splits the difference for corroded or coated material. Match that to a rod classification and you get a sound weld; guess, and you get a defect with a name.
• Prep and fit-up decide the outcome. Root openings, bevel angles, land dimensions, and backing requirements exist because fusion is a geometry problem as much as an amperage problem.
• Technique follows the symbol. Fillet leg size tells you how many passes, length and pitch tell you where stops and starts land, and a multi-pass callout means controlling interpass temperature, not just stacking beads.

The last point deserves emphasis because it is the one new welders skip: a diagram communicates intent, not just dimensions. When a symbol calls for a 5/16 in fillet weld, all around, with a specific sequence, someone downstream is going to load that joint, inspect it, or weld to it under pressure. Reading the drawing before striking an arc is the cheapest quality control step in the entire process, and it costs nothing but attention.

Build the Skill with Reps, Not Guesses

Symbol literacy works like any other trade skill: it improves with repetition. You would not expect to lay a clean cap after one afternoon of practice, and reading a weld symbol chart fluently takes the same kind of exposure. Print the chart, keep it on the bench, and every time you cut or fit a piece of scrap, sketch the symbol for the joint you are about to weld. Then weld it and check whether the result actually matches what you drew.

That scrap practice builds the loop that separates a technician from someone who just melts metal: see symbol, choose rod, set polarity, dial amperage, run the weld, inspect the result, adjust. Do it fifty times and the AWS A2.4 standard stops feeling like a codebook and starts feeling like a language you read at a glance.

Keep a few trusted references within arm’s reach while you learn:

1. The current AWS welding symbol chart for daily reference and the A2.4 standard for edge cases.
2. An electrode classification breakdown so the E7018 or E6010 code on the rod wrapper always makes sense.
3. A practical electrode selection guide covering position, current, and base metal.
4. The WPS for whatever coded work you take on, plus the applicable code, such as AWS D1.1 for structural steel.

If your work expands beyond mild steel, the same diagram-first habit transfers directly. Alloy steels demand careful filler matching, as our alloy steel welding electrodes guide explains, and even a shift to aluminum processes starts with reading the joint and prepping the surface correctly, which is exactly what proper aluminum cleaning before welding comes down to.

From Reading to Earning

There is a saying among welders that a “dime-worthy” weld is one you would show off, uniform ripples, clean ties, no undercut, correct size. What separates those beads from porosity and rejection is rarely hand speed. It is decisions made earlier: correct polarity, correct electrode for the position and the steel, correct prep, and correct reading of what the drawing asked for.

So the next time a print lands in front of you, resist the reflex to grab a rod and go. Trace the arrow, find the reference line, identify the symbol, check the tail, confirm the polarity, confirm the electrode, check your fit-up. Only then strike the arc. Do that consistently and the diagram stops being the intimidating part of the job, it becomes the part that tells you exactly how to win.

Read it right, set it right, weld it right. That is the whole game.

Frequently Asked Questions

What is a stick welding diagram?

A stick welding diagram can refer to a wiring/setup diagram for the machine or a weld symbol diagram showing the joint. For drawings, it’s the AWS weld symbol that tells you the weld type, size, location, and prep needed for shielded metal arc welding (SMAW).

Which polarity is best for stick welding?

It depends on the electrode. Most cellulose and many all position rods like E6010 run well on DCEP (reverse polarity) for deep penetration. Low hydrogen rods like E7018 often run on DCEP or AC depending on brand; always check the electrode packaging per AWS classification.

How do I read a welding symbol for stick welding?

Start at the arrow pointing to the joint. The reference line holds the weld symbol (arrow side below or above indicates which side). The tail may list the process/spec. Dimensions like size go left of the symbol, length/spacing to the right. Refer to AWS A2.4 for details.

What electrode should I use for a fillet weld on mild steel?

For general purpose mild steel (A36), E6013 is easy for thin material/flat positions, E7018 is great for stronger, low hydrogen code work, and E6011 is good for dirty/rusted material or AC machines. Choose based on position, cleanliness, and requirements.

Why does E7018 need to be kept dry?

E7018 is a low hydrogen electrode. Moisture in the coating can introduce hydrogen into the weld, increasing the risk of hydrogen induced cracking (HIC), especially on thicker, restrained, or higher strength steels. Store in a rod oven per manufacturer recommendations.

What does the number in E7018 mean?

Per AWS A5.1, E means electrode, 70 means minimum tensile strength of 70,000 psi, 1 means all position welding, 8 means low hydrogen iron powder coating compatible with AC or DCEP depending on exact specification.

Do I need to follow a WPS when reading a stick welding diagram?

For non-code work general guidance is fine, but for code/structural work you must follow the Welding Procedure Specification (WPS). The diagram/symbols on drawings may reference the WPS which governs polarity, preheat, electrodes, passes, etc.

Can I use AC for all stick electrodes?

No. Some electrodes like certain E6010 variants prefer DCEP for best arc stability/penetration, while others like E6011 are designed for AC or both. Check the electrode classification’s fourth digit and packaging for compatible current/polarity.

What’s the difference between weld symbol and welding symbol?

A weld symbol indicates the type of weld (fillet, groove, plug, etc.). A welding symbol is the complete symbol including reference line, arrow, tail, dimensions, and supplementary symbols as defined in AWS A2.4.

Where can I find official stick welding symbol standards?

The primary standard is AWS A2.4 (Standard Symbols for Welding, Brazing, and Nondestructive Examination) published by the American Welding Society. Other relevant references include AWS A5.1 for carbon steel electrodes and applicable codes (e.g. AWS D1.1).