Stick Welding (SMAW) Guide: Electrodes, Amperage & Technique

How SMAW Works: The Arc, the Flux, and the Slag

In stick welding, a flux-coated consumable electrode carries the welding current from the machine, through the electrode holder (stinger), across an air gap to the workpiece. When the tip touches and is drawn back roughly the width of the rod, the circuit ionizes the gap and sustains an electric arc burning at 6,000 to 10,000 degrees F. That heat melts both the base metal and the steel core of the rod, and droplets of molten filler transfer across the arc into the weld pool.

The flux coating is what makes the process work outdoors. As it burns it does three jobs at once: it releases a shielding gas (largely carbon dioxide) that displaces atmospheric oxygen and nitrogen, it forms a glassy slag blanket that floats to the top of the pool to protect it while it solidifies, and it adds deoxidizers and alloying elements that clean the weld metal. Because the shield is generated at the arc itself, SMAW works in wind that would blow away the external gas shield of MIG or TIG, which is why it dominates structural steel, pipeline, farm and repair work.

After each pass you chip and wire-brush the slag off. Trapped slag is one of the most common weld defects, so slag removal and interpass cleaning are not optional. The tradeoffs versus wire processes are lower deposition rate, more operator skill for a clean start and restart, and the stub loss of throwing away the last two inches of every rod.

• Core wire: Carries current and becomes filler metal; diameter (3/32, 1/8, 5/32 in.) sets the amperage range.
• Flux coating: Generates shielding gas, forms slag, and adds deoxidizers/alloys; its chemistry defines the electrode class.
• Slag: Protective glass layer that must be chipped and brushed between passes to avoid inclusions.
• Arc length: Keep it roughly equal to the core-wire diameter; too long causes spatter, porosity and undercut.

Reading the AWS Electrode Classification

Carbon-steel stick electrodes are classified under AWS A5.1 (and A5.5 for low-alloy rods) with a code like E7018. The 'E' means electrode. The first two digits (three on 70,000+ psi rods) are the minimum tensile strength of the deposited weld metal in thousands of psi: 60 means 60,000 psi, 70 means 70,000 psi. The third digit is welding position: 1 = all positions (flat, horizontal, vertical, overhead), 2 = flat and horizontal fillet only.

The last digit, read together with the third, encodes the flux type and the usable current. That is where E6010, E6011, E6013 and E7018 diverge in personality even though several share the same tensile strength. A suffix after a dash, such as E7018-1 or E7018-H4R, denotes improved toughness, low-hydrogen (H4 = 4 mL per 100 g of deposited weld metal) or a moisture-resistant coating (R).

The four workhorse rods below cover the vast majority of what a beginner-to-intermediate welder will ever touch. Learn these before branching into E7014 (easy iron-powder fill), E6011 for dirty scrap, or stainless and hardfacing electrodes.

• E6010: Cellulosic coating, snappy arc, tight puddle. Runs DCEP (reverse) only. Master the whip-and-pause for open-root pipe.
• E6011: The AC-capable cousin of 6010. Slightly more spatter, but the rod of choice on old-school transformer welders and farm repairs.
• E6013: Rutile coating that lights easily and leaves a clean bead on thin steel. Forgiving for learners but shallow penetration on thick joints.
• E7018: Low-hydrogen iron-powder rod. Strong, ductile, X-ray-quality welds, but the flux absorbs moisture and must be kept dry (see storage below).

Polarity: DCEP, DCEN and AC

Polarity determines where the heat concentrates and it is one of the most misunderstood settings for new welders. In direct current, roughly two-thirds of the arc heat is on the positive side. DCEP (Direct Current Electrode Positive), also called DC reverse polarity, puts the electrode on the positive lead, concentrating heat in the rod for deeper penetration into the base metal. DCEN (Direct Current Electrode Negative), or DC straight polarity, puts more heat in the workpiece, giving faster melt-off and shallower penetration.

The rule of thumb for stick: most rods run DCEP for maximum penetration and a stable arc. E6010 is DCEP only. E7018 runs DCEP or AC. E6013 is happy on anything, and some fast-fill or sheet applications intentionally use DCEN to keep from burning through thin material. AC (alternating current) reverses direction 60 times a second, splitting the heat evenly; it is what old transformer 'buzz-box' machines produce, and it cures arc blow, the magnetic wandering of the arc that plagues DC welding near the end of long joints or on magnetized pipe.

If your bead is piling up cold and sitting on top with poor fusion, or your 7018 arc is fluttering and spattering, check polarity first: a rod run backward (DCEN when it wants DCEP) is a classic cause. Confirm your machine's leads: on most inverters, moving the ground and stinger between the + and - terminals sets the polarity.

• DCEP (reverse): Electrode positive. Deep penetration, stable arc. Default for 6010 and 7018 on DC machines.
• DCEN (straight): Electrode negative. Faster deposition, shallow penetration. Used on thin sheet with 6013 to avoid burn-through.
• AC: Splits heat 50/50, needed for 6011/6013 on buzz-boxes and the best fix for arc blow on magnetized material.

Setting Amperage by Rod Diameter

Amperage is driven mainly by electrode diameter, then trimmed for position, joint thickness and polarity. A practical starting rule is about 1 amp per 0.001 in. of rod diameter as a midpoint: a 1/8 in. (0.125 in.) rod centers around 125 amps. From there, drop 10 to 15 percent for vertical-up and overhead work so the puddle does not sag, and nudge up for flat, thick, well-fixtured joints.

Match rod diameter to plate thickness. A good default is to keep the electrode diameter at or below the base-metal thickness: use 3/32 in. rods on 1/8 in. and thinner sheet, 1/8 in. rods on 3/16 to 1/4 in. steel, and step up to 5/32 or 3/16 in. only on plate that is 3/8 in. and thicker where you want deposition. Running a big rod hot on thin steel is the fastest route to burn-through for a beginner.

Read the puddle, not just the dial. If the arc is hard to strike and stubs out, or the bead is narrow and ropey with poor tie-in at the toes, you are too cold, add amps. If you get chronic undercut, excessive spatter, a wide flat washed-out bead or the rod glowing red and its coating cracking off before it is spent, you are too hot, back off. The chart below gives realistic flat-position starting windows on DCEP; always confirm against the manufacturer's rod-can label, which lists the tested range.

• Quick math: About 1 amp per 0.001 in. of diameter as a midpoint (1/8 in. rod ~ 125 A), then adjust.
• Out of position: Reduce 10-15% from flat-position amperage for vertical-up and overhead to control the puddle.
• Duty cycle: A 200 A machine at 40% duty cycle can weld only ~4 of every 10 minutes at 200 A before it must cool, size the welder to the amperage you actually run.

Rod Ovens and Low-Hydrogen 7018 Storage

E7018 is a low-hydrogen electrode, and its strength comes with a maintenance demand: the flux coating is hygroscopic and pulls moisture from the air. That moisture breaks down into hydrogen at the arc, and dissolved hydrogen causes cracking in the weld and heat-affected zone, especially on thicker or higher-strength steel. This is the mechanism behind hydrogen-induced (cold) cracking that can show up hours or days after welding. Cellulosic rods like 6010, by contrast, deliberately contain moisture and never go in an oven.

AWS D1.1 Structural Welding Code and most fabrication procedures require low-hydrogen electrodes to be baked and held. New rods come in hermetically sealed cans or vacuum packs. Once opened, they go into a heated rod oven (holding oven) kept at roughly 250 to 300 F to stay dry. Standard, non-moisture-resistant 7018 that has been exposed to shop air beyond the code-allowed window (commonly about 4 hours for 70-ksi rods, less in humid conditions) must be reconditioned by rebaking at roughly 500 to 800 F per the manufacturer's spec, not just rewarmed. An '-R' rod (E7018-H4R) has a moisture-resistant coating and a longer allowable exposure, but the same principle applies.

For the home hobbyist welding non-critical work, this is less of a hard rule, but for anyone welding to a code or on anything structural, a rod oven is not optional. Buying advice: a small 10 lb bench holding oven runs roughly 100 to 250 USD, a 50 lb shop oven 300 to 600 USD, and portable 12 V oven tubes for the truck 150 to 350 USD. If you only weld occasionally, buy 7018 in small 5 to 10 lb sealed cans rather than a 50 lb box so each seal is fresh, and keep an unopened can in a sealed ammo box with desiccant as a field workaround.

• Hold temperature: Keep opened low-hydrogen 7018 at ~250-300 F in a heated oven; the flux must stay dry.
• Exposure limit: Typical 7018 (non-R) is limited to roughly 4 hours of shop-air exposure before rebaking is required under AWS D1.1 procedures.
• Rebake vs. hold: A holding oven keeps dry rods dry; it does NOT redry damp rods. Wet 7018 needs a high-temp rebake (~500-800 F) per the maker's spec or must be scrapped.
• Never oven 6010/6011: Cellulosic rods need their moisture; baking them ruins the arc.

Running the Weld: Root, Fill and Cap

A full-penetration groove weld on plate or pipe is built in three stages, and each has its own rod, amperage and technique. The root pass fuses the two members at the bottom of the joint, the fill passes build the joint up to near-flush, and the cap is the finished crown on top. On thin single-pass fillet welds you may do all of this in one run, but understanding the three-stage logic is what separates a welder from a bead-runner.

Root: on open-root pipe and heavy structural, E6010 (or E6011 on AC) is the classic choice because its digging arc reaches the back of the joint and achieves full penetration with a controlled keyhole. Run it a touch colder, with a whip-and-pause or a slight upward drag, keeping a tight arc so the keyhole stays about 1.5 rod diameters wide. Too hot and the keyhole grows and blows through; too cold and you get lack of penetration and a cold-lapped root.

Fill and cap: after chipping and brushing the root slag, switch to E7018 for its strength, low hydrogen and smooth, self-leveling bead. Fill passes are run hotter and wider, often with a slight side-to-side weave or straight stringers, tying into both sidewalls to avoid lack-of-fusion. The cap is a final controlled weave that stays inside the bevel edges, leaving reinforcement no more than about 1/16 in. proud with even ripples and no undercut at the toes. General technique holds throughout: correct arc length (about one rod diameter), a 5 to 15 degree drag (backhand) travel angle for 7018, steady travel speed that keeps the slag line trailing behind the puddle, and a proper restart where you strike ahead of the crater, come back to fill it, then move on.

• Root pass: E6010/6011, tight digging arc, controlled keyhole for full penetration at the joint bottom.
• Hot pass: On pipe, a fast, hot second pass burns out root porosity and slag before the fill.
• Fill passes: E7018 run hotter/wider, tie into both sidewalls, clean slag between every pass.
• Cap: Stay inside the bevel edges, ~1/16 in. reinforcement, no undercut, even ripples.
• Travel angle: Drag (backhand) 7018 and 6013 at 5-15 degrees; the slag should follow, never lead, the puddle.

Common Defects and How to Fix Them

Most stick-welding problems trace back to a handful of causes: amperage, arc length, travel speed, angle, or contaminated/damp material. Learning to diagnose the bead is the core skill. The defects below account for the overwhelming majority of failed bend tests and rejected inspections on structural and pipe work, and every one of them has a controllable root cause.

Porosity, the gas holes in or on the bead, comes from moisture (damp 7018), oil, paint, galvanizing or an arc length that is too long, letting atmosphere into the pool. Undercut, the groove melted into the base metal at the toe of the weld, is caused by too much amperage, too long an arc, or too steep a work angle. Slag inclusions come from poor interpass cleaning or letting the slag run ahead of the puddle. Lack of fusion and lack of penetration come from too little heat, travel too fast, or wrong rod for the joint. Cracking is usually hydrogen (wet low-hy rod) or high restraint/rapid cooling on thick or high-carbon steel, addressed with dry rods and, where the procedure calls for it, preheat.

• Porosity: Dry the rod, clean the steel (oil/paint/galv), shorten the arc. Check for damp 7018 first.
• Undercut: Lower amperage, shorten the arc, reduce weave width, and pause at the toes on the cap.
• Slag inclusions: Chip and brush every pass; keep the arc/puddle ahead of the slag line; grind out trapped starts.
• Lack of fusion/penetration: Add heat, slow down, choose a deeper-penetrating rod (6010) and open/prep the joint.
• Cracking: Use dry low-hydrogen rods, apply required preheat/interpass temp, and avoid quenching thick or high-carbon steel.
• Arc blow: Switch to AC, reposition the ground clamp, wrap the work lead, or weld away from the magnetized end.

Sourcing Electrodes and Equipment

Stick consumables are one of the most widely stocked welding items in the country, carried by welding-supply distributors, industrial-gas branches and farm/hardware stores across all 50 states. Buying advice from a long-time distributor perspective: match the brand tier to the job. Premium lines (Lincoln Excalibur/Fleetweld, Hobart, ESAB Atom Arc) run cleaner and more consistently for code and pipe work; value/import rods are fine for practice, tacking and non-critical farm repair. Do not judge two cans of '7018' as identical, coating consistency and moisture control vary widely.

Expect rough national pricing of about 20 to 45 USD for a 10 lb box of 1/8 in. 7018 and 15 to 35 USD for 6010/6013, with 50 lb boxes running 70 to 180 USD depending on brand and alloy. Prices move with steel and nickel markets, so stainless (E308/309/316) and low-alloy rods cost substantially more. Always confirm the AWS classification and any suffix (H4R, -1) printed on the box against your welding procedure, and check the date/lot on sealed low-hydrogen cans.

For machines, a 120/240 V inverter stick welder in the 140 to 200 amp class covers most hobby and light-fabrication needs for roughly 250 to 700 USD; engine-driven welders for pipeline and off-grid field work run several thousand. When you buy, ask your local distributor about matching filler to base metal, required PPE (an auto-darkening helmet rated to the correct shade, typically DIN 10-13 for stick, plus leathers and respiratory protection per OSHA 1910.252/.1000 for fumes), and rod-oven options. Use the WeldIndex directory to find welding and industrial-gas suppliers near you, compare which brands they stock, and request quotes from distributors nationwide before committing to a bulk consumable order.

• Brand tier: Premium rods (Lincoln, Hobart, ESAB) for code/pipe; value rods for practice and non-critical repair.
• Ballpark price: ~20-45 USD per 10 lb box of 1/8 in. 7018; 50 lb boxes ~70-180 USD; stainless/low-alloy cost notably more.
• Check the box: Verify AWS class, suffix (H4R/-1) and lot/date, especially on sealed low-hydrogen cans.
• Machine class: A 140-200 A inverter (~250-700 USD) suits most hobby/light fab; engine-drive for field and pipeline.
• PPE: Auto-darkening helmet (DIN 10-13), leathers, gloves and OSHA-compliant fume ventilation/respiratory protection.

Frequently Asked Questions