What Does Dig Do in SMAW Welding? Arc Force Explained

A student welding an open-root pipe pass keeps stopping to pry a frozen 6010 rod off the joint, while the instructor’s identical machine lays the root in one continuous bead. The difference wasn’t skill or amperage — it was a small dial labeled “Dig” that neither of them had ever touched.

What \”Dig\” Means When You’re Welding with the SMAW Process

The student was welding an open-root pipe pass, and every few seconds the 6010 rod froze to the joint. He’d stop, pry it loose, strike again, and watch his instructor lay the same root in one continuous bead on the machine next to him. Same rod, same amperage, same joint prep. The only difference was a small dial labeled \”Dig\” that the student had never touched.

So what does dig do when welding using the SMAW process? In short, dig is a machine setting that pushes extra current into the arc the moment the electrode gets close to or touches the work, so the rod doesn’t freeze to the plate and the arc keeps driving into the joint. The word also describes an arc characteristic: a \”digging\” arc that cuts aggressively into the base metal instead of sitting softly on top of it. The two meanings are related but distinct, which is exactly why beginners get lost when a pipe welder tells them to turn the dig up.

In shielded metal arc welding (SMAW), better known as stick welding and called manual metal arc (MMA) welding in much of the world, a consumable electrode with a flux coating melts into the puddle while the coating decomposes into shielding gas and slag that protect the molten metal from the atmosphere. It’s the most widely taught welding process on the planet, and dig is one of its most misunderstood controls.

The Two Meanings of \”Dig\” in Stick Welding

Keep these apart from the start:

• Dig the setting. Also labeled arc force, force, or simply dig on the machine’s front panel, this is an adjustable function on modern constant-current inverter power sources. Turning it up makes the machine momentarily boost its output current when arc voltage collapses, meaning the electrode tip approaches or short-circuits against the work. The result: the rod refuses to stick, restarts come easier, and the arc punches deeper into the root and sidewalls.
• A digging arc. This is an arc behavior, not a knob position. A digging arc is forceful, crisp, and penetrating. It’s the classic signature of fast-freeze cellulose electrodes like E6010 and E6011, which are the standard choices for open-root pipe passes and structural root and tack work. You can have that arc character with dig turned down, because the electrode’s coating chemistry creates it.

Why You Mostly Hear the Term from Pipe and Structural Welders

Beginners rarely run into dig in a flat fillet class, because a comfortable drag on clean plate doesn’t demand it. The term circulates in pipe and structural crews for a practical reason: their work combines tight root gaps, out-of-position passes, and fast-freeze rods, precisely the conditions where a rod wants to stick and a root wants to freeze mid-stride. Ask a structural welder how they keep a 6010 root from washing out or a 7018 vertical-up from freezing at the tie-in, and the answer often involves arc force.

How Machines Expose Dig Today

Modern constant-current inverter machines, the kind sold by Lincoln Electric, Miller, and ESAB, typically expose dig as a knob or menu item scaled from 0–100% or 0–10, with higher numbers meaning a stronger current boost during a short. Older transformer and engine-driven machines generally don’t offer an adjustable dig at all; they carry a fixed, drooping arc characteristic that builds in a certain amount of sticking resistance as a design feature. If your machine has no dig label, that doesn’t mean your arc behaves like everyone else’s, it means the characteristic is fixed at whatever the manufacturer engineered in.

One more distinction worth making early: dig is specific to arc processes like SMAW. It doesn’t translate directly to wire processes, where different controls shape the arc, nor to Aluminum Flux Welding: How It Works and When to Use It, where the process physics run on entirely different principles.

What the Rest of This Article Covers

Once you understand both meanings of the word, everything else falls into place. We’ll start with the arc physics that make dig necessary, sort out dig versus inductance versus polarity, look at what actually happens inside the machine when you turn the dial up, and then walk electrode by electrode, 6010, 6011, 6013, 7018, 7024, through what dig does for each. From there you’ll find position-specific guidance, a symptom-by-symptom troubleshooting table, safety considerations when spatter and fume increase, and a step-by-step routine for dialing dig in on five common jobs.

The goal is simple: you should finish able to answer the question in one sentence, and more importantly, know exactly which direction to turn the dial when the rod sticks or the puddle gets too violent to control.

SMAW Arc Basics: Why Penetration, Arc Force, and Dig Are Connected

Before the dig dial makes sense, picture what happens in the fraction of an inch between rod tip and plate. Stick welding looks like a shower of sparks, but the arc is a controlled electrical event, and every machine control is a way of shaping it. Once arc length, voltage, current, and heat click together, dig stops being mysterious.

What Actually Happens Inside the Arc Gap

Strike the electrode and two things start at once. Electrons boil off the hottest point of the rod tip through thermionic emission, while gases in the gap ionize into a conductive plasma channel we call the arc stream. That stream carries current between a cathode zone and an anode zone, each generating intense localized heat. On direct current the split between them is uneven, which is one reason polarity changes how a bead sits in the joint.

In SMAW the arc’s heat is shared three ways: it melts the core wire, it melts the flux coating into shielding gas and slag, and it melts the base metal. The balance shifts with arc length, amperage, and electrode chemistry. That is the fundamental reason a setting like dig exists: it changes how much current is available at the moment the arc gap nearly closes. For a broader look at why stick welding still leads in field conditions, see Advantages of Stick Welding: Why SMAW Still Wins.

Arc Voltage Follows Arc Length

Arc voltage is essentially a measure of how far the electricity has to jump. Lengthen the arc and voltage climbs; shorten it and voltage drops. The practical effect: a long arc spreads heat over a wide, soft area, while a tight arc concentrates it into a narrow point. This is why root passes are run with a deliberately short arc, keeping energy at the bottom of the joint instead of washing the sidewalls. Technical references from TWI describe arc voltage as the primary variable a welder manipulates by hand in manual processes.

Constant Current: The Machine Holds Amperage, Not Voltage

Most SMAW power sources are constant-current machines with a drooping output curve. Set 110 amps and the machine works to deliver roughly 110 amps across a wide range of arc voltages; you control voltage by moving the rod. That division of labor matters: the machine governs how much metal melts per second, while your hand governs how that heat is distributed.

There is a limit to how tight you can go. As the rod approaches the plate, voltage keeps dropping until the gap becomes metal-to-metal contact. At that point the arc extinguishes, the circuit shorts, and the rod can fuse to the workpiece. Manufacturers such as Miller and Lincoln Electric build dig or arc force circuits precisely to manage that moment.

Penetration and Fusion Are Not the Same Thing

This distinction trips up beginners more than any other. Fusion is the bonding of weld metal to base metal along the joint faces. Penetration is how deep that fusion extends into the root and sidewalls. A bead can look beautiful on the surface and still fail because it never fused to the bottom of a groove. Both AWS D1.1 and the ASME Boiler and Pressure Vessel Code treat penetration and fusion as separate acceptance criteria, which is why visual appearance alone never qualifies a weld.

How Arc Force Shapes the Weld Pool

Current flowing through the arc creates a magnetic jet that pushes against the molten pool. More current at the moment of contact means a stronger jet, a deeper crater, and a pool that wets into the joint corners instead of piling up in the middle. Too little force and the puddle sits high and round, leaving cold overlap at the toes; too much and the jet gouges the root, opens undercut, or blows clean through thin stock. Dig adds that force temporarily, without changing your base amperage for the whole pass.

Why Rods Stick: The Stubbing Cycle

Stubbing is a lag problem. As the electrode nears the plate, resistance in the circuit climbs and arc voltage collapses, but current cannot jump instantly because the machine’s output inductance resists rapid change. For a fraction of a second the rod is touching the work with too little current to keep the arc alive and too much contact to release it. The tip freezes to the plate, and yanking it free leaves a stub and a cold spot. Dig works by detecting that low-voltage condition and pushing current above the setpoint fast enough to eject the shorted droplet and re-establish the arc before it can lock in. Getting a clean restart without tearing the rod loose is one of the skills emphasized in an All Position Welding Rod Guide.

With this physics in place, the next question becomes practical: which knob are you actually turning when someone says dig, and how does it differ from arc force or inductance?

Dig Control vs. Arc Force vs. Inductance: Sorting Out the Terminology

Walk around a welding shop and you will hear three words used interchangeably: dig, arc force, and inductance. They are not interchangeable. Mixing them up is one of the fastest ways to chase your tail while tuning a machine, because each control acts on a different part of the welding circuit. Once you can separate them, the dial in front of you stops being mysterious and starts being a tool.

Dig and Arc Force: Two Names for One Current Boost

Dig and arc force describe the same function. The machine watches for the moment your electrode tip touches, or nearly touches, the workpiece. When arc voltage collapses toward zero, the power source momentarily pushes output current above your setpoint. That short burst of extra amperage melts the bridging droplet, blows the rod free, and re-establishes the arc instead of letting the electrode freeze in place. The same boost also drives the arc a little harder into the joint when you are working in a tight gap.

Manufacturers simply label it differently. Lincoln Electric uses the word “Dig” on its stick and multi-process machines. Miller and several other builders print “Arc Force” or simply “Force” on the panel, and ESAB machines commonly use “Arc Force.” If you see a control that makes the rod stop sticking and adds a little crackle to the arc, you have found the same function regardless of the word on the knob.

Inductance: The Rate-of-Rise Control

Inductance answers a different question. Dig asks how much current the machine pushes during a short; inductance asks how fast that current is allowed to climb. Raise inductance and the current ramps more slowly through each short circuit, so the wire or rod wets into the puddle gently, the arc sounds softer, and spatter drops. Lower it and current snaps upward, giving a crisp, fast arc response with a harsher pop and more spatter.

The critical distinction: inductance shapes the transition, it does not hold current up. It will never rescue an electrode that is freezing to the plate the way dig will. On MIG machines, inductance is the main spatter-and-feel knob; on AC/DC stick machines it appears less often, but where it exists it changes arc character, not sticking resistance.

Polarity: The Setting Dig Cannot Replace

Polarity decides where the heat sits in the arc, and dig cannot correct it. With electrode positive (DCEP), roughly two-thirds of the arc heat concentrates at the anode, which in a stick setup is the electrode tip, pushing a deeper, narrower profile into the base metal. Reverse it to DCEN and heat shifts toward the work, changing penetration shape and deposition completely. The same rod at the same amperage will behave like a different product. For a broader look at how these choices shift results across processes, our Advantages of Stick Welding guide walks through the trade-offs. Polarity also changes rod performance in vertical and overhead positions independently of any dig setting.

Slope, or current ramp, is a fourth, less common control. It sets how quickly the machine moves from open-circuit voltage to your welding current, softening arc starts. It affects the beginning of the arc, not the short-circuit recovery that dig handles.

Quick Comparison of the Four Controls

Control	What it changes	What you see/hear	Typical use	Too high	Too low
Dig / Arc Force	Amperage during a momentary short	Harder crackle, rod pops free	Root passes, vertical, restarts, tacking	Spatter, undercut, burn-through, rough bead	Sticking, stubbing, cold restarts, frozen root
Inductance	Rate of current rise in a short	Softer or crisper arc sound	MIG spatter control, arc feel	Mushy arc, cold-appearing ties	Harsh arc, heavy spatter
Polarity	Heat distribution between arc ends	Penetration depth, bead shape	Matched to electrode type	Wrong rod behavior entirely	Weak penetration, poor fusion
Slope / Ramp	Speed of current rise at arc start	Start softness	Soft-start machines	Sluggish, wandering starts	Aggressive, popping starts

What Actually Happens Inside the Machine When You Turn Dig Up

Before a dig setting makes sense, picture what the power source does when you are not even striking an arc. A stick machine is a constant-current (CC) source: you dial in the amperage, and the machine holds that current while arc voltage floats up and down with arc length. Engineers draw this as a \”drooping\” output curve. Across normal arc lengths it is nearly flat, so current stays close to your setpoint; at both extremes it falls away steeply. At one end sits open-circuit voltage, typically 60–80 V with no current flowing. At the other end, where the electrode tip touches the plate and voltage collapses toward zero, is exactly where dig lives.

With dig at zero, current follows that steep section downward: as the gap shortens, the machine lets amperage sag and the rod welds itself to the work. Turn dig up and the machine does the opposite, pushing current above the setpoint while it sees the low-voltage condition, then snapping back the instant the arc restrikes. Dig does not change the amperage you set for ordinary arc lengths; it only changes what happens in the final millimeter before a stick.

The Five Beats of a Dig Boost

1. The gap closes. The tip approaches the plate, arc voltage drops with it, and the arc stream shortens and stiffens.
2. The machine reads a short. Once voltage falls below a low threshold, the control logic treats it as contact rather than a normal arc.
3. Current is driven above the setpoint. The output stage boosts amperage for a brief moment, packing extra energy into the arc zone.
4. The short is blasted apart. Metal at the contact point heats almost instantly, the trapped droplet is ejected, and the gap reopens.
5. Normal operation resumes. Voltage recovers, current falls back to your setpoint, and the bead continues as if nothing happened.

That fifth beat is the whole point: the arc re-establishes itself instead of cooling into a frozen stub you pry loose with pliers. It also explains why dig acts like a ballast, a reactive response rather than a permanent amperage increase.

Why Inverters Respond in Milliseconds

Older transformer-rectifier machines relied on magnetic components to alter the output, so their response to a short was sluggish and coarse, and many had no dig function at all. Modern inverter power sources switch their output stage electronically at tens of kilohertz, letting them sense the voltage collapse and change current within a millisecond or two, genuinely sub-cycle behavior. That speed is why an inverter’s dig feels crisp while a big engine welder feels sluggish by comparison, and it is part of what keeps stick welding competitive, a trade-off we explore in our take on the advantages of stick welding. Manufacturers such as Miller document the same control logic under names like arc force or dig, so the mechanism described here applies broadly across brand-name machines.

What You Feel at the Electrode — and What It Costs

Turn dig up and the changes are audible before they are visible. Restarts get snappier, the arc bites with a sharper crackle instead of a soft sizzle, and the rod stops freezing even when you jam the tip into the puddle. Welders running vertical-up roots or open-root pipe describe it as the machine helping push the rod through the tight spots.

The price shows up in three places:

• Spatter. A higher peak current during each boost flings more molten metal outward, and bead edges come out rougher.
• Heat and penetration. More current through the same moment means a hotter, deeper crater, which is welcome in a root pass and unwelcome on thin sheet.
• Fume volume. The momentary current spike burns more coating and lifts more particulate, so fume generation rises precisely when the boost fires.

That last point is a real ventilation concern. OSHA’s ventilation requirements for welding, cutting, and brazing call for mechanical ventilation whenever welding takes place in a confined or inadequately ventilated space, and a higher-dig arc simply adds to what your booth, hood, or local exhaust has to capture.

The practical takeaway: dig is a controlled, short-duration exception to your set current, engineered to keep the arc alive. Use enough to stop the sticking, then stop, because every notch beyond that buys spatter, roughness, and fume you did not need. MIG machines handle the same short circuit differently, as our aluminum MIG setup guide explains, but on a stick machine dig is the specific tool for the job.

How Different SMAW Electrodes Behave with Dig: 6010, 6011, 6013, 7018, 7024

Dig is not a universal dial. The covering on a stick electrode shapes the arc so strongly that the same setting can help on one rod and ruin the bead on another. So decode what is stamped on the electrode first. Under the AWS A5.1 classification system, E6010 breaks down like this: the E means electrode, 60 is the minimum tensile strength of deposited weld metal in thousands of psi (60,000 psi), the 1 means the rod is qualified for all positions, and the final digit identifies the covering chemistry. A 7018 follows the same pattern: 70,000 psi, all positions, low-hydrogen iron-powder covering. Decode those digits and you can predict how a family will respond to dig before you strike an arc.

E6010 and E6011: Cellulose Rods That Already Dig

E6010 and E6011 use fast-freeze cellulose coverings that burn with a forceful, spraying arc and bite hard into the joint root, which is why they remain the classic open-root pipe rods. The chemistry matters: E6010 runs on DC electrode positive only, while E6011 runs on AC or DC, making it the choice for simple AC buzz boxes and engine-driven machines. Both coverings produce elevated diffusible hydrogen by design, a trade-off for their deep, cleaning arc.

Because the arc is already aggressive, keep dig moderate on cellulose rods. Cranking it up adds little useful penetration and a lot you cannot use: blow-through on thin-wall roots, an oversized keyhole, and ragged toes. The real benefit is restart behavior and stub prevention during the quick, tight-arc work of a root pass.

E6013: The Soft Arc That Rarely Needs Dig

E6013 rods have a thin titania covering that produces a soft, quiet, shallow-penetrating arc, friendly to beginners and ideal for sheet metal repair and out-of-position touch-up. Dig is rarely needed. High dig on a 6013 shows up fast as burn-through on light gauge, spatter across the panel, and a bead that looks hammered rather than laid down. If a 6013 keeps sticking, the usual culprits are amperage too low or arc length too long, not a hungry dig setting. Our All Position Welding Rod Guide: Types, Uses & Tips compares how these all-position rods behave across positions and materials.

E7018: Buttery Arc, Small Amounts of Dig

E7018 is a low-hydrogen iron-powder electrode with a smooth, quiet, almost buttery arc and a forgiving puddle. In structural work it is normally run as stringer beads with a slight drag, rewarding steady technique over machine tricks. A small amount of dig earns its keep in vertical-up root and fill passes, where the rod stays close to the puddle for long stretches and can freeze to the work at an awkward moment. Restraint is the trick: too much dig throws spatter under the slag, roughens the profile, and disrupts the calm puddle you want. The same covering chemistry appears in low-alloy variations, which is where our Alloy Steel Welding Electrodes: Selection, Use & Safety guide is worth reading.

E7024: The Drag Rod Where Dig Barely Matters

E7024 is a heavy iron-powder covering made for flat and horizontal fillet welds (note the position digit 2). You drag it, the arc stays buried, and deposition is high. Because the rod never gets close enough to short against the work during a normal drag technique, dig has almost nothing to respond to. Leave it low or off and spend your attention on travel speed and arc length.

Open-Root Pipe Sequencing: Dig at Each Stage

A typical open-root pipe run changes rods mid-job, and it makes sense to change dig with them:

• Root with 3/16 in. E6010: moderate dig for clean restarts and to keep the rod from freezing when you pause to reposition the keyhole.
• Hot pass with E6010 or a fast-freeze AC rod: dig slightly higher, since this pass burns off slag inclusions and restarts frequently over the root.
• Fill and cap with E7018: drop dig back down. The rod is held close in vertical-up, but a calm arc lays smoother, cleaner stringers.

Electrode	Arc character	Starting dig	Watch for
E6010 (DCEP)	Forceful, deep	Moderate	Blow-through, fat keyhole
E6011 (AC/DC)	Forceful, deep	Moderate	Spatter on AC, rough toes
E6013	Soft, shallow	Low or off	Burn-through on light gauge
E7018	Smooth, quiet	Low to moderate	Spatter trapped under slag
E7024	Soft, buried	Low or off	Llittle visible effect

The takeaway is simple: the more aggressive the rod’s own arc, the less dig you should add. Match the setting to the covering, verify amperage first, and let technique do the rest.

Position, Joint Type, and Material Thickness: When Dig Earns Its Keep

The dig setting that saves a vertical root pass can ruin a piece of 18-gauge sheet. Dig is not something you set once and forget. Its value and its risk shift with where the puddle sits, how hard gravity pulls on it, and how much metal is there to soak up heat. Reading that relationship separates arc force used as a precision tool from arc force used as a blunt instrument.

Flat Grooves and Fillets: Where Dig Matters Least

In the flat position, gravity works with you. The puddle settles into the joint, and the electrode has no reason to freeze mid-travel, so dig does very little useful work. If a rod keeps sticking in a flat fillet, the culprits are almost always a long arc, wrong polarity, lazy travel speed, or amperage too low for the diameter. Fix those first, starting off the maker’s recommended range, before you touch the arc force dial. Most all position welding rod choices are already forgiving enough in flat work that extra dig only adds spatter.

Vertical-Up: The Welder Against Gravity

Vertical-up groove welds flip the equation. You are supporting a molten pool against gravity with a tight arc and a small weave or keyhole, and the leading edge constantly tries to cool and freeze as you move. Electrode freeze-out in root and hot passes is a top defect cause in vertical work. Moderate dig keeps the puddle fluid long enough to tie into the sidewalls, which prevents cold lap at the tie-in and stops the rod locking itself to the plate mid-strike. Push it too far and the pool turns aggressive and hard to contain, showing up as undercut and a rough, sagging profile.

Open-Root Pipe and Keyhole Control

This is where dig earns its reputation. An open-root pipe pass with a fast-freeze 6010-type rod is run by holding a small keyhole open at the leading edge of the puddle while you move uphill. Insufficient dig shows up two ways: the rod freezes when you pause, and the root fails to fuse on the back side because the arc lacks the punch to drive through. Too much dig widens the keyhole faster than you can close it, and the root drops through or blows open. Tuned right, the keyhole responds the way your hand expects, which is why pipe instructors make arc force one of the first variables students learn to tune.

Overhead: Helpful Restarts, Dangerous Excess

Overhead benefits from dig mainly during restarts, where a stubborn re-ignition can otherwise leave a lump hanging in an uncomfortable position. Once the bead is running, extra arc force works against you: the puddle is already held up by surface tension, and a more violent arc can blow it out of position and drop molten metal toward you.

Thin Sheet vs. Heavy Sections

On thin-gauge material, typically 16 to 18 gauge in auto body and HVAC work, excessive dig raises heat input at the point of contact. The result is burn-through, distortion, and excess penetration on the back side of the joint, so less dig is almost always the safer direction. Thick structural members, chamfered grooves, and field tacking sit at the opposite end. Tacks on heavy plate are notorious for freezing the rod the instant you touch down, and a solid dig setting is what keeps a tack from sticking when access and angle are awkward.

Base Metal Conditions That Shift the Answer

Surface condition matters as much as position. Mill scale and heavy rust insulate the arc and invite wandering, so welders add arc force when a grinder would solve the problem properly. Galvanized coatings put zinc in the arc, raising fume and spatter, so cranking dig on galvanized stock compounds an already messy situation. Aluminum stick welding with AC 4043/E4043 rods is a different animal again, and prep is everything, so review proper technique in aluminum cleaner for welding guidance before blaming dig for a dirty, wandering arc. Clad and heat-sensitive alloys generally want less instantaneous force and more controlled heat.

Position / Joint	Dig Tendency	What You’re Managing
Flat groove or fillet	Low	Gravity assists fusion; technique matters more
Vertical-up root and hot pass	Moderate	Pool freeze-out and cold lap at tie-ins
Open-root pipe (keyhole)	Moderate, tuned	Holding keyhole open without blowing through
Overhead	Low to moderate	Restarts only; excess blows the puddle out
Thin sheet, 16-18 gauge	Minimal	Burn-through, distortion, back-side pearling
Thick structural, tacks	Moderate to high	Rod freezing on contact

Dig earns its keep wherever gravity, tight access, or an awkward restart threatens to freeze the rod, and it becomes a liability on thin metal that punishes extra heat. Match the setting to the joint, and the dial stops being a mystery.

Troubleshooting: Symptoms of Too Much Dig and Too Little Dig

When a stick weld goes wrong, dig is the first dial welders reach for — and it is usually the wrong first move. Freezing, spatter, undercut, and burn-through can all be dig problems, but each one has a longer list of causes that have nothing to do with arc force. Remember what dig actually does in the SMAW process: it adds a momentary current boost when the electrode short-circuits against the puddle, so the arc does not stall. It fixes arc instability, not heat input, travel speed, or cleanliness. Diagnose in the right order: check the rod, the settings, the technique, and the metal before you touch the knob.

Signs Your Dig Setting Is Too Low

Too little dig leaves you fighting the electrode. The classic symptoms show up fast:

• Freezing and stubbing. The rod tips weld itself to the workpiece every time you shorten the arc. This is the textbook low-dig symptom, especially with 7018 in vertical-up and 6010 on a root pass.
• Ugly restarts. The arc sputters, stalls, or won’t re-ignite cleanly when you restrike on a crater.
• Lack of fusion into the sidewalls. The bead sits on the joint faces instead of tying in, because the momentary current boost that would punch into the gap never arrives.
• Cold lap at the toes. Rolled-over, unfused edges where the puddle solidified before it wetted out.
• Inconsistent root penetration. On an open root, the keyhole opens and closes unpredictably, giving alternating heavy and thin sections.
• Out-of-position wrestling. In vertical work the puddle freezes mid-stride and you end up chipping, grinding, and restarting instead of running one continuous bead.

Signs Your Dig Setting Is Too High

Too much dig trades sticking for violence. Expect:

• Excessive spatter that sticks to the plate, the surrounding area, and your leathers.
• Undercut at the bead toes — and here is the trap: undercut is driven by travel speed, amperage, and arc placement. Turning dig up while chasing undercut almost always makes it worse.
• Burn-through on thin material, particularly 16–18 gauge sheet, where the current spike punches straight through the root.
• A rough, irregular bead profile with a lumpy, disturbed surface instead of smooth ripples.
• Over-penetration at the root that has to be ground out before the next pass.
• Heavier fume and more arc blow on DC circuits, since the short-circuit current spike drives more metal transfer across the gap.

Look-Alike Problems That Aren’t Dig’s Fault

This is where most misdiagnosis happens. Wrong amperage produces sticking (too low) or burn-through and spatter (too high) on its own. Wrong polarity changes penetration and bead shape entirely — a 7018 run on DCEN behaves like a different electrode no matter what the dig dial says. A long arc causes spatter, poor penetration, and a wandering puddle. Dirty, rusty, or mill-scaled base metal causes fusion problems that no amount of arc force fixes; if you are working on aluminum, aluminum cleaner for welding matters far more than any machine setting. And the wrong electrode for the position — for example, a flat-only rod run overhead — will make you blame a setting that was never the problem. If you need to rethink rod choice by position, this all position welding rod guide covers the common AWS families.

Quick Troubleshooting Table

Symptom	Likely cause	Dig adjustment	Other checks
Rod freezes or stubs on contact	Dig too low	Raise in small increments	Amperage within the rod’s range; strike like a match, don’t jab
Arc won’t restart cleanly	Dig too low, or technique	Raise slightly	Restrike on clean metal, not in the crater center
Lack of fusion at sidewalls	Travel speed, amperage, or dig	Try a small increase	Slow down, correct weave, clean the joint
Cold lap at toes	Heat and technique	Usually leave it alone	Amperage up, slower travel, tighter arc
Excessive spatter	Dig too high, or long arc	Lower it	Shorten arc length, verify polarity
Undercut at bead edges	Travel speed and arc placement	Lower if anything	Slow down, keep the puddle pushed to the toe
Burn-through on thin sheet	Dig too high, amperage too high	Lower it	Drop amperage, use a softer rod, stitch the joint
Rough, lumpy bead	Dig too high, or bad arc length	Lower it	Consistent drag angle and arc length
Porosity or cracks in the bead	Moisture, contamination, shielding	No dig effect	Bake/store rods dry, clean the plate, check polarity

The reliable diagnostic order is simple: confirm the electrode is dry and correct for the position, set amperage from the manufacturer’s range, run a bead on matching scrap, fix your arc length and travel speed, clean the base metal — and only then adjust dig. When the other variables are right, a small dig change usually resolves the last stubborn symptom. When they are not, the dial just masks it.

Safety, Fume Control, and Shop Practices When Using Higher Dig

Dig is a dial, but it behaves like an exposure control. When you turn it up, the machine pushes current above your setpoint every time the arc length collapses, which means a harder blast of energy, more molten metal thrown from the puddle, and a larger plume of fume off the electrode and the workpiece. That trade-off is manageable, but only if you treat the setting as part of your safety planning rather than a purely metallurgical one. A welder who quietly bumps dig from 30 to 70 percent on a long vertical pass has changed the spatter rate and the fume load for the rest of the shift.

Ventilation, Local Exhaust, and What Is Actually in the Fume

Welding fume is not one substance. It is a shifting mixture of metal oxides, flux decomposition products, and gases released from the coating, the base metal, and any contamination on the surface. The coating matters: cellulose rods such as E6010 produce a different gas and fume profile than low-hydrogen iron powder rods such as E7018, and burning off paint, plating, or mill scale adds whatever was on that surface into the breathing zone. Ventilation should therefore be sized for the work and the consumable, not for the dig percentage on the display.

The governing rule is straightforward. Under OSHA 1926.353, welding, cutting, and brazing operations require either general ventilation or, where contaminants exceed exposure limits, local exhaust such as fume extraction arms and hoods. If engineering controls cannot bring exposure into limits, respiratory protection is required under a written program.

Three metals come up repeatedly in stick welding fume:

• Manganese — present in steel and electrodes, associated with neurological effects with chronic overexposure.
• Hexavalent chromium — generated when stainless or chromium-bearing alloys are welded; a separately regulated toxicant.
• Zinc — released from galvanized coatings, the cause of classic metal fume fever with flu-like symptoms after heavy exposure.

Use source-capture extraction where you can reach the arc, general dilution ventilation as a baseline, and a correctly selected respirator only as the last layer. NIOSH maintains the underlying exposure research and respirator certification framework behind those decisions (CDC/NIOSH).

Hot Work, Fire Prevention, and PPE

OSHA 1926.352 requires fire prevention measures during welding and cutting: remove combustibles where possible, otherwise protect them with fire-resistant covers, and provide a fire watch where sparks and slag can travel to concealed spaces. Higher dig throws hotter, farther-reaching spatter, so this matters more at the end of a dig-heavy job, especially overhead or out-of-position work where slag drops. NFPA guidance on hot work reinforces the same practice (NFPA), and the basics of the overall program are summarized on OSHA’s welding, cutting, and brazing page.

PPE stays constant regardless of the dial: an auto-darkening helmet with an appropriate shade for your amperage, flame-resistant leathers, gloves, hearing protection, and safety glasses under the hood. Inspect the electrode holder, ground clamp, and cable jackets before every shift. Frayed insulation and a loose ground clamp create resistance heating and a shock path, both of which get worse when dig is pushing extra current through the circuit. Keep hands and floors dry, never weld in standing water, and remove the plug or open the disconnect when servicing equipment. Cylinder handling follows the same discipline: caps on when in use, cylinders secured upright, regulators clean, and oxygen kept from oil and grease; a practical overview sits in our Air Gas Welding Supply: Gases, Cylinders & Safety Guide.

Stay Inside the Qualified Procedure

On code work, dig is not a personal preference. Welding to AWS D1.1 or ASME Section IX means working within a qualified procedure where essential variables, including machine settings and heat input, have been tested and documented. Changing dig casually can move a weld outside its qualified range, and the paperwork will not reflect it. The same care applies when you select consumables for alloy or out-of-position work, as covered in our Alloy Steel Welding Electrodes: Selection, Use & Safety guide. Procedure qualification belongs to the welding engineer or supervisor, and standards resources from AWS and ASME define those rules.

Step-by-Step: Dialing In Dig for Five Common SMAW Jobs

The fastest way to understand dig is to set it deliberately, on purpose, with a plan. The routine below works on any stick machine with an arc force or dig control, and it takes about ten minutes on scrap before you strike a single bead on real work.

The General Setup Routine

1. Confirm electrode and polarity first. Check the rod’s AWS classification and required polarity (DCEP, DCEN, or AC) before anything else. Polarity changes penetration and bead shape on its own, independent of dig.
2. Set amperage from the manufacturer’s published range for that diameter and your material thickness. Lincoln, Miller, and ESAB all publish recommended ranges by rod diameter, and those numbers should be your starting point, not a guess.
3. Run a test bead on scrap of the same thickness as your joint. Same steel, same position, same cleanliness.
4. Adjust technique and amperage until the bead is right — then, and only then, touch the dig control. Dig only modifies machine behavior near a short circuit, so a wrong amperage setting can’t be fixed by it.
5. Start at a moderate dig value, test for sticking, then move in small increments while watching spatter, bead profile, and penetration into the root and sidewalls.

Five Jobs, Five Starting Points

1. Open-root pipe, 3/16 in. E6010 root pass (DCEP). Typical amperage lands roughly in the 75–100 A range for 3/16 in. diameter, depending on wall thickness and fit-up. Set moderate dig. The root is where tight arc length matters most, and a short 6010 arc is exactly the condition where the rod wants to freeze. Watch the keyhole: dig should let you hold a tight arc without the rod grabbing, but too much will blow the keyhole open and eat through the land. If the root is washing through, lower dig before you touch amperage.

2. E7018 vertical-up fill, 3/4 in. plate (DCEP). Set amperage in the published range for the diameter (commonly around 130–170 A for 1/8 in. rod), then add a small amount of dig. Fighting gravity means a short arc and a slow, steady climb; a modest dig boost keeps the puddle from freezing mid-stride without disturbing the slag. Too much dig here shows up as a rough, rippled bead and spatter that sticks to the surrounding surface. If you’re seeing undercut at the toes, back dig off before blaming travel speed alone. For a refresher on rod choices in vertical positions, see our All Position Welding Rod Guide: Types, Uses & Tips.

3. E6013 sheet repair, 16 gauge (DCEP or AC). Amperage is low — roughly 30–40 A for a 1/16 in. rod — and dig should stay low or off. The arc is soft and the metal is thin; a high dig value punches straight through. Here, dig earns its keep only if you’re restarting frequently and the rod keeps tacking itself to the seam. Even then, nudge it slightly rather than cranking it.

4. E7018 flat fillet, structural members (DCEP). Flat, thick, and gravity-assisted: dig matters little. Set proper amperage, hold a normal arc length, and leave dig near the middle or lower end of its range. Higher values buy nothing here except spatter and fume volume.

5. Field tacking and out-of-position repair on dirty plate (DCEP). This is where dig genuinely shines. Mill scale, light rust, and awkward access make tacks prone to sticking, and each frozen rod costs time and damages the coating. A higher dig setting lets you touch down hard and restart cleanly. Clean the joint anyway — dig helps fusion, but it doesn’t replace a wire brush.

Job	Electrode	Polarity	Amperage (typical)	Dig tendency	Watch for
Open-root pipe root	E6010 3/16 in.	DCEP	~75–100 A	Moderate	Keyhole blow-through
Vertical-up fill	E7018 1/8 in.	DCEP	~130–170 A	Low–moderate	Rough bead, toe undercut
16 gauge sheet repair	E6013 1/16 in.	DCEP/AC	~30–40 A	Low or off	Burn-through
Flat fillet, structural	E7018	DCEP	Per diameter chart	Low	Unnecessary spatter
Field tacks, dirty plate	6010/7018	DCEP	Per diameter chart	Moderate–high	Spatter, fume

Amperage figures above are general guidance for common diameters; always defer to your electrode manufacturer’s published range for the exact rod and thickness in front of you.

If you’re new to stick welding and want the broader context on why these settings matter, our piece on the Advantages of Stick Welding: Why SMAW Still Wins covers where SMAW still outperforms wire processes in the field.

Common Mistakes, Myths, and the Bottom Line on Dig in SMAW

Dig is one of the most misunderstood controls on a modern stick welder. It sits within easy reach, it changes the arc dramatically in an instant, and it sounds like a performance upgrade, so it often becomes the first knob people turn and the first thing they blame when a weld looks wrong. In practice, dig is a supporting feature with a narrow job description. The mistakes below are the ones that cost welders time, material, and credibility.

Mistakes That Give Dig a Bad Name

• Using dig to compensate for wrong amperage. Amperage, arc length, travel speed, and electrode selection are the four variables that actually govern penetration and bead profile. Dig is a support feature, not a substitute for any of them. If your bead is sitting on top of the plate, turning dig up is treating a symptom while the real problem — usually cold amperage or a long arc — stays in place.
• Cranking dig to fix undercut or porosity. Undercut comes from too much heat in one spot, a long arc, or travel speed that outruns the puddle. Porosity comes from gas, moisture, and dirt: wet low-hydrogen rods, oil, paint, mill scale, or a draughty breeze. More arc force adds spatter to all of it and cures none of it.
• Treating dig as a penetration knob on thin sheet. On 16 to 18 gauge steel, extra current punch is how you blow holes. Thin material rewards a soft arc and disciplined travel speed, not force.
• Ignoring polarity. DCEP, DCEN, and AC change penetration and bead shape independently of dig. Setting a perfect dig value on the wrong polarity still gives you the wrong weld.
• Assuming every machine has it. Many older transformer and engine-driven machines have no adjustable dig at all. On those, the operator’s arc-length control is what keeps the rod from freezing, which is a technique skill worth developing regardless of what you weld on today. If you are weighing a machine upgrade, our look at the advantages of stick welding covers where SMAW still outperforms other processes.
• Adjusting code-work settings without a WPS. On work governed by AWS D1.1 or ASME Section IX, machine settings including dig sit inside a qualified procedure range. Changing them casually can put the weld outside its qualified range and the documentation that supports it.
• Skipping procedure qualification. If you change a variable that matters, the honest next step is re-qualifying, not hoping nobody asks. The American Welding Society and ASME both publish the qualification frameworks this falls under.

Three Myths Worth Dropping

“More dig always equals deeper welds.” Dig peaks only during a momentary short. Once the arc is burning normally, your amperage, arc length, and travel speed decide depth, not the dig percentage.

“Dig replaces technique.” No setting fixes a wandering hand. Dig buys you a fraction of a second when the rod touches down; a controlled root still comes from body position, consistent arc length, and rhythm.

“Dig and inductance do the same thing.” They overlap in conversation and nowhere else. Inductance controls how quickly current rises during a short, which softens or crisps the feel and changes spatter. Dig actively holds current up during that short to prevent sticking. One shapes the arc’s manners; the other keeps it alive.

The Bottom Line on Dig in SMAW

• Dig prevents sticking and makes restarts and out-of-position work easier.
• It costs you something: more spatter, a rougher bead surface, and a visible increase in fume.
• Correct amperage, clean base metal, and sound technique always come first.
• Polarity and electrode choice decide the weld before dig ever gets a vote.
• On qualified code work, the procedure outranks your preference.

The plain answer to the original question: dig is a machine setting that briefly pushes current above your setpoint when the arc shortens, so the electrode doesn’t freeze to the work and the arc drives into the joint instead of dying. Learn it by turning it down, running a root, then raising it a notch at a time until the rod stops grabbing and the spatter hasn’t yet gotten out of hand. Practice on scrap of the same thickness as your real joint, and if you are still building your electrode vocabulary, our all position welding rod guide is a useful companion to this article. Dig will not make you a better welder, but knowing exactly what it does — and refusing to lean on it — will keep your arcs honest.

Frequently Asked Questions

What does dig do when welding using the SMAW process?

Dig (also called arc force or force) briefly boosts the welding current when the electrode gets close to or touches the work. That momentary surge prevents the rod from freezing to the joint and helps the arc punch into the base metal, which is especially useful in vertical and root-pass work.

Is dig the same as arc force or inductance?

Dig and arc force are names different manufacturers use for the same function — a current boost during a short circuit. Inductance is different: it controls how fast current rises during a short, softening the arc and reducing spatter, but it does not hold current up the way dig does.

Do all stick welders have a dig setting?

No. Most modern inverter constant-current machines offer an adjustable dig or arc force control, while many older transformer and engine-driven machines have a fixed arc characteristic with no adjustment. On machines without it, arc-length control is your substitute.

What happens if I turn dig up too high?

Excessive dig produces heavy spatter, undercut at the bead toes, a rougher bead profile, and burn-through on thin material. It can also increase fume generation at the moment of each boost, so ventilation matters more when you run a aggressive setting.

What happens if dig is too low?

The electrode sticks or stubs frequently, restarts become clumsy, and you are more likely to get lack of fusion or cold lap, particularly in vertical-up and open-root work where the puddle freezes quickly.

Which electrodes need the most dig?

Fast-freeze cellulose rods like E6010 and E6011 in out-of-position and root passes benefit most, since they already dig aggressively and are prone to freezing when arc length drops. Soft-arc rods like E6013 and drag rods like E7024 rarely need much dig.

Does dig replace setting the correct amperage?

No. Amperage, polarity, arc length, travel speed, and electrode choice determine penetration and bead shape. Dig only changes how the machine behaves near a short circuit, so always set amperage correctly first and then fine-tune dig.

Can I change dig settings on code or certified welds?

Only within the limits of your welding procedure specification. Work built to standards such as AWS D1.1 or ASME Section IX must follow qualified procedures, and machine settings within those procedures should not be changed casually.

Does a higher dig setting create more welding fume?

Higher dig increases instantaneous current and metal expulsion during short circuits, which can raise spatter and momentary fume output. Use proper ventilation and, where required by OSHA, local exhaust or respiratory protection regardless of the setting.

How do I know what dig setting to start with?

Set amperage from the manufacturer’s recommended range for your electrode diameter and material thickness, weld a test bead on similar scrap, then start dig at a moderate level. Increase it only if the rod sticks; decrease it if you see excess spatter, undercut, or burn-through.