Vertical Arc Welding: Positions, Techniques & Tips

A first-year welder once ran a perfect 3G root on 12mm plate, only to have the cap reject on undercut at both toes — heat, angle and timing were fine, but the pause at the edge wasn’t. Vertical arc welding punishes tiny timing errors that flat work never reveals, which is why it is the position that separates hobbyists from structural welders.

What Vertical Arc Welding Is and Why It Is the Hardest Position

Vertical arc welding is simply arc welding in which the weld axis runs up and down rather than horizontally. The seam is oriented vertically, and you move the electrode either upward, called vertical-up or uphill, or downward, called vertical-down or downhill. That single detail, which way the puddle is travelling against gravity, changes almost everything about heat, speed, timing and the way a finished weld looks.

The definition is simple. The execution is not. In flat welding the puddle sits in the joint and holds itself. In vertical work the molten metal wants to run down the face of the plate before it freezes, so every parameter you take for granted has to be re-tuned. Compared with flat welding, vertical welding calls for lower heat input, a shorter arc and a slower, more deliberate travel speed, plus constant attention to where the leading edge of the puddle is sitting.

Why Gravity Makes Vertical Welding Hard

A welding puddle is a small pool of liquid steel held in shape by surface tension. Lay the joint flat and surface tension wins easily. Stand it up and gravity starts pulling that liquid metal toward the bottom of the joint the instant it forms. The result, if you do nothing about it, is a bead that sags in the middle, washes out at the bottom and leaves the root starved of metal at the top.

To fight this, the welder has to freeze the puddle faster than gravity can move it. That means:

• Reduced amperage — most welders drop 10 to 15 percent below their flat-setting current, and sometimes more for out-of-position root passes.
• A tighter arc — a long, soft arc dumps heat into a wider area and gives the puddle more time to run.
• Controlled travel speed — too fast and the bead is cold and starved; too slow and the excess liquid simply drains downward.
• Puddle support — through weave shape, pause timing and, on uphill work, a small shelf of frozen metal that each new increment of puddle rests on.

It is also physically demanding. Your hands are working above shoulder height, often in a fixed posture, for minutes at a time. A useful overview of how position work is taught and why instructors put such weight on body positioning is available from The Fabricator’s welder training essentials on positioning.

Where Vertical Welds Actually Appear

This is not an academic position. Any structure that grows upward or is fabricated in place contains vertical welds:

• Building and bridge columns and their splice joints
• Tank and pressure vessel shells, where shell plates are welded vertically seam by seam
• Ship hulls and offshore platform legs
• Pipeline girth joints in fixed terrain, where the pipe cannot be rotated into flat position
• Heavy equipment frames, boiler shells and repair work in the field

Whenever a structure is too large to turn, the welder has to go up instead. That is why vertical capability is one of the clearest dividing lines between a hobbyist welder and a structural welder, and it is the reason Advantages of Stick Welding: Why SMAW Still Wins still matters on jobsites, since stick remains the most portable way to run a vertical root in the field.

Uphill Is the Default, and Codes Say So

Direction of travel is not a personal preference in most structural work. AWS D1.1 requires vertical groove welds to progress upward for all passes, with narrow exceptions such as performing downhill passes to repair undercut when preheat of at least 70 °F (20 °C) is maintained. Downhill has a legitimate place on thin material and on some pipe standards, but on thick structural plate it risks a lack of fusion because the arc is outrunning the puddle into cold base metal. For a fuller treatment, see WeldPundit’s vertical welding overview, and for the general relationship between welding position and joint geometry, Lincoln Electric’s Arc Magazine master class is a solid companion read.

How This Article Is Organized

We will next nail down the formal position designations, 3G, 3F and 4G, and the angle tolerances that test plates allow. From there the article moves through the uphill-versus-downhill decision, electrode and consumable selection, a full vertical-up technique breakdown, machine settings for SMAW, GMAW, FCAW and GTAW, a defect troubleshooting table, qualification and WPS requirements, safety and ergonomics, and finally a practice plan you can run on your own plate. By the end you should be able to strike an arc on a vertical joint knowing exactly why every setting is where it is.

Vertical Welding Positions Explained: 3G, 3F, 4G and Angle Limits

Before anyone can teach you to weld vertical, they have to agree on what vertical actually is. The industry does that with a short code: a digit for where the joint sits in space, and a letter for the joint type. Read it once and a fabrication drawing, a welding procedure specification and a qualification card all start making sense. The system is not decorative either. Position dictates your body position, your electrode choice, your heat settings, and whether the bead you just laid down counts as acceptable under the governing code.

Groove, Fillet and the Numbers 1 to 4

AWS plate designations combine a number (1 through 4) with a letter. The number describes the orientation of the joint: 1 is flat, 2 is horizontal, 3 is vertical and 4 is overhead. The letter describes the joint itself: G for groove, F for fillet. Put them together and you get eight plate positions:

Designation	Joint type	Position	What it looks like
1G	Groove	Flat	Plate lying flat, weld on the top face
2G	Groove	Horizontal	Plate plumb, weld runs side to side
3G	Groove	Vertical	Plate plumb, weld runs up or down
4G	Groove	Overhead	Plate overhead, weld from below
1F	Fillet	Flat	Tee joint flat, fillet on top
2F	Fillet	Horizontal	Tee joint plumb, fillet on the side
3F	Fillet	Vertical	Tee joint plumb, fillet welded up or down
4F	Fillet	Overhead	Tee joint overhead, fillet from below

Two of these dominate structural work. 3G is the vertical groove test: plate set plumb, a bevel or V-groove welded running either uphill or downhill. It shows up in performance qualification more than any other plate position because it exposes every mistake gravity can magnify. 3F is the fillet equivalent, usually a tee joint welded in the vertical plane. Fillet work is more forgiving since you are not chasing full fusion through a root face, but the familiar problems still appear: sagging fillets, undercut at the top toe, and a heavy crown where the pause timing went wrong.

4G sits directly alongside 3G in most training programs. The bevel, the tacks and the bead sequence are essentially identical; only your body position changes. Overhead forces the puddle to hang while vertical forces it to stack, so many shops run the two tests back to back. Whether one qualification covers the other depends entirely on the standard you are working to, so read the qualification table in your governing code instead of assuming a hierarchy.

Where Vertical Starts: The Angle Rules

Vertical is not a vibe, it is a measured range. The position tables define a vertical weld with two angles at once. The first is inclination: how far the weld axis sits off horizontal, covering 15° to 80°. The second is weld face rotation: the direction the face of the weld points as it travels around the axis, running from 80° to 280°. Between 80° and 90° of inclination, essentially plumb, the face may rotate a full 360° and the weld is still called vertical.

That last rule is what keeps real fabricators out of trouble. A seam climbing a nearly upright tank shell shifts clock position as it wraps around, and a column flange or stair stringer rarely sits at a textbook 90°. As vertical welding resources explain, joints in the field land at odd angles far more often than they land perfectly plumb, and the code bands exist so those joints can still be classified and qualified.

Practically, this means you should measure rather than eyeball. A stair stringer at roughly 45°, a gusset welded on a slope, or a pipe standing at 75° may all be worked as vertical technique while carrying a different designation on the traveler. The technique transfers; the paperwork does not.

ISO 6947: PF and PG on International Drawings

ISO 6947 runs alongside the AWS system on international work, with different letters. Its PF and PG designations cover the vertical position and roughly correspond to the US 3G test position, with one useful addition: direction of travel is built into the symbol. PF is vertical welded upward, PG is vertical welded downward. A European procedure therefore tells you the progression before you strike an arc, while a bare “3G” does not. Never assume uphill from a US designation alone. If you are moving between codes, training resources that compare position systems are worth reading, because the two frameworks also measure inclination and face rotation differently.

Once you know which position you are facing and which direction the weld runs, the next decision is the consumable. An electrode rated for all positions only helps if you can actually hold the position, so match the rod to the joint with our All Position Welding Rod Guide. And if you are building toward paid qualification work through a formal program such as an aluminium welding course, expect these designations in your first week: position literacy is the entry fee for every test that follows.

Vertical Up vs Vertical Down: Choosing the Right Progression

Ask two experienced welders which way to run a vertical bead and you will often get two different answers. Both are right, because progression is not a matter of preference. It is a decision driven by material thickness, electrode type, code requirements and how much penetration the joint actually needs.

The Core Trade-Off: Gravity Works Both Ways

When you weld vertical up (uphill), the solidifying trailing edge of the puddle sits below the arc, so it supports the molten metal that follows. You get deeper penetration and heavier deposits per pass, but at the cost of travel speed and total heat input into the plate.

When you weld vertical down (downhill), the arc leads and the puddle chases it toward the floor. The arc is still cutting into the top edge of the joint while the puddle is thin and fast, so penetration is shallower, heat input is lower, and the finished bead is flatter with far less distortion. Speed is the obvious bonus: downhill progress is typically two to three times faster than uphill on light material.

The Thickness Rule of Thumb

Lincoln Electric’s guidance is the practical starting point most welders learn first: material under 1/4 inch (6 mm) usually favors downward progression because it delivers lower heat input and less distortion on thin sections, while material thicker than 1/4 inch is usually best welded vertical up for deeper penetration and larger deposits (Lincoln Electric, Master Class). Think of 6 mm as the natural tipping point where the benefits of speed stop outweighing the benefits of penetration.

Electrode Compatibility Matters More Than You Think

Not every consumable is designed to travel in both directions:

• E6010, E6011 and E6013 operate in either direction. Cellulosic rods like E6010 are the downhill favorite because they dig hard and freeze fast on a fast-moving puddle. Your All Position Welding Rod Guide covers which rods genuinely earn an all-position rating.
• E7018 low-hydrogen electrodes are generally not recommended for vertical down. Their slag is fluid and slow-setting; running downhill lets the slag run ahead of the arc and trap itself in the weld, causing slag inclusions and lack of fusion. E7018 belongs to vertical up, where the support puddle and slower travel let the slag solidify behind the arc.
• For higher-strength and specialty steels, always confirm the manufacturer’s position rating before deviating from the default direction, as covered in Alloy Steel Welding Electrodes: Selection, Use & Safety.

What the Codes Say

Industry practice is split, and the split follows the work:

• AWS D1.1 structural steel defaults to uphill for groove welds on plate and heavy sections. Deep penetration and sound root fusion matter more than speed in a building or bridge connection.
• API 1104 pipeline welding is built around downhill progression with cellulosic electrodes, where production speed on a girth bead and clean, fast-freezing roots are the priority (API 1104, Welding of Pipelines and Related Facilities). The same root-cap philosophy shows up in the U.S. Department of Transportation pipeline specs (49 CFR Parts 192/195 welding specifications).
• ASME Section IX and most performance qualification ranges treat uphill and downhill as distinct variables: qualification in one direction does not automatically qualify the other unless the procedure states both.

Practical industry discussion of these choices appears regularly at WeldPundit’s vertical welding overview.

Decision Table: Which Direction to Run

Condition	Best Progression	Why
Under 6 mm (1/4 in), low-carbon sheet	Vertical down	Low heat, low distortion, high speed
Over 6 mm, structural groove	Vertical up	Deep penetration, large deposits
Root pass, pipeline girth weld	Vertical down (cellulosic)	Fast freeze, controlled penetration
E7018 or low-hydrogen cap pass	Vertical up	Prevents slag entrapment
Open-root or out-of-position fit-up	Vertical up	Puddle support, better tie-in
Thin-wall tubing, cosmetic work	Vertical down	Clean profile, minimal burn-through
Heavy plate, full-penetration code weld	Vertical up	Meets D1.1/ASME fusion demands

When in doubt, check the WPS first, then the thickness, then the electrode. The progression that respects all three will almost always be the correct one.

Choosing Electrodes and Consumables for Vertical Work

Consumables are the cheapest performance upgrade you will ever buy, and vertical is where the choice shows up first. A rod that runs beautifully flat can turn ugly the moment the puddle has to hang against gravity: it grows too fast, the slag runs ahead of the arc, and the toes freeze without tying in. Before you adjust technique, make sure the electrode class, coating and shielding gas are actually suited to vertical progression.

Match the Electrode Class to the Pass

Vertical joints are rarely welded with one rod from root to cap. The standard structural approach pairs a fast-freeze or penetrating rod for the root with a low-hydrogen fill and cap:

Class	Coating	Vertical role
E6010 / E6011	Cellulosic	Root passes, including the keyhole technique on pipe open roots; aggressive penetration, fast-freeze puddle, easy restarts
E7018	Basic, low-hydrogen	Vertical-up fill and cap on structural plate and 3G groove tests; smooth, controllable puddle
E7014	Titania with iron powder	Fast-fill cover passes where the procedure allows it; less forgiving of long arcs
E7024	High iron powder	Flat and horizontal only — keep it out of vertical work

The cellulosic E6010 deserves special mention. Its deep, narrow penetration is exactly what supports the keyhole root technique welders rely on for open-root pipe, where you are burning through and re-forming a small hole in the joint face as you go. Once the root is sealed, most procedures switch to E7018 for the hot pass onward. For a broader look at how these classifications work across positions, our all position welding rod guide breaks down the AWS digit codes, and the alloy steel welding electrodes guide covers what changes when the base metal is not plain carbon steel.

Amperage and Arc Length: The Two Numbers That Matter

Vertical is not the place to run a flat-current setting and fight the puddle. Because travel speed is slower and the arc stays in one place longer, most welders drop amperage before starting. A typical E7018 3/32 in vertical fill setting runs about 70–90 amps, roughly 10–15% below the flat value for the same electrode. Drop to 1/8 in and the same principle applies: reduce from the flat recommendation, then tune by puddle behavior rather than by dial number.

Arc length is the second habit to tighten. In vertical-up, keep the arc at about 1 to 1.5 times the electrode diameter — roughly 3–5 mm for stick welding. Longer than that and you lose shielding, widen the bead and invite undercut at the toes; the temptation to stretch the arc as the rod shortens is one of the most common faults in student welds, as Lincoln Electric’s technique clinic points out (Lincoln Electric, Master Class).

Gas Shielding Choices for Wire Processes

If you run FCAW or GMAW vertically, shielding gas does real work. Gas-shielded flux core (dual-shield) in vertical-up is a structural favorite because the slag-forming flux supports the puddle the way a stick coating does. Common choices are 100% CO₂, which gives deeper penetration but more spatter, and an argon/CO₂ blend that runs smoother with a calmer arc. Short-circuit GMAW is popular for thin vertical sheet precisely because its lower heat limits sag. Review Airgas welding supplies and gas options if you are still deciding what to keep in the shop, and remember that gas choice interacts with transfer mode — a setting that works flat may not transfer cleanly uphill.

Low-Hydrogen Storage: Protecting the Coating

Basic electrodes like E7018 absorb moisture from shop air, and that moisture becomes hydrogen in the arc. Hydrogen shows up later as porosity, cracking and delayed failures that no amount of technique will fix. Low-hydrogen electrodes must be kept in a heated electrode oven or a sealed quiver from the moment the container is opened; typical holding temperatures sit around 250–300°F (120–150°C), with rebake cycles specified by the manufacturer and the applicable code. Field welders who leave rods out overnight, or carry them in an unsealed pouch for a full shift, are rebuilding the moisture problem they were trying to avoid.

Get these four variables right — class, current, arc length and dryness — and the technique described in the next section becomes far easier to execute.

Vertical-Up Technique: Angles, Weaves and Pass Sequence

When a vertical-up bead goes wrong, welders blame amperage first. More often the fault is geometry and rhythm: the rod tilted a few degrees too far, a weave wider than the puddle could feed, or a pause at the toe half a beat short. Lock the angles, choose the right motion for the pass, and the bead builds itself.

Work Angle and Travel Angle: The Starting Geometry

Work angle is how far the electrode points left or right of the joint centerline; travel angle is how far it leans along the direction of travel. On a vertical butt (groove) joint, hold the work angle at 90°, so the arc splits its heat evenly between both plates. On a tee or fillet joint, shift to roughly 45°, aiming into the corner where the two members meet. Past those numbers, one leg of the joint takes the heat while the other just sits there, which shows up later as cold lap or a lopsided face.

Travel angle stays small: 5° to 15° uphill. That slight lean directs the arc force into the leading edge of the puddle and helps the weld metal climb instead of sag. A steep travel angle pushes heat into the plate and piles metal behind the arc; almost no angle leaves the arc sitting on top of a fluid puddle that wants to run downhill. As welding training literature on body and torch positioning points out, consistent angles start with a stable body: brace your forearm or wrist against the plate, keep your shoulder relaxed, and let the joint guide your hand rather than steering from the elbow.

Stringer Beads or a Weave: When to Move Sideways

Stringer beads, meaning no side-to-side motion, remain the default for the root and most fill passes. They keep heat input low, deposit a narrow and sound bead, and are far easier to repeat. Weaving only pays when the joint is wide enough that a single stringer cannot cover a layer, or when you need to tie into both bevel walls in one pass.

If you do weave, keep it tight. The general ceiling is about 3/4 in (20 mm) of total weave width. Beyond that the puddle gets too wide to shield and too hot to hold, the center of the bead sags, and the edges starve. For wider grooves, use a split weave: run two overlapping stringers or half-weaves per layer, each covering roughly half the width and tying into the previous one, instead of stretching one motion across the whole face. For rod choices that stay controllable in this position, see our All Position Welding Rod Guide: Types, Uses & Tips.

Weave Patterns and Pause Timing

Different passes call for different shapes of motion:

• Straight or slight zigzag: root and hot pass. Small movements keep the keyhole controlled and the root from blowing open.
• Z or crescent weave: fill passes. Move diagonally up and across, then back, covering the bevel walls evenly.
• Triangular weave: useful when the joint opens wide, because the motion places metal at the root line first and then fans out to the toes.
• J or triangular-corner motion: fillet and tee work, where the top toe needs extra dwell to avoid sagging.

The timing inside every one of those patterns is the same: hesitate distinctly at the outer edges of the bevel, then travel faster across the face. The puddle needs that beat at the toe to melt into the sidewall and fill the crater behind the arc’s edge. Rush the corner and you get undercut; dwell too long and the corner turns into a cold overlap. Lincoln Electric’s master-class guidance on vertical progression emphasizes the same idea: the weave should look like a steady rhythm, not a series of stops, with the slow part at the edges and the quick part in the middle.

Pass Sequence: Root, Hot, Fill and Cap

Pass	Goal	Motion	Watch for
Root	Fully fused, slightly concave backing	Straight or tiny side-to-side, slight keyhole	Blow-through from too much heat; lack of fusion from too little dwell
Hot	Lock the root in and burn out trapped slag	Narrow weave or stringer, slightly hotter than root	Wash the root edges completely; don’t leave a shadow line
Fill	Build thickness in controlled layers	Z or triangular weave, ≤20 mm wide	Interpass temperature and sidewall tie-in
Cap	Flat, even-faced reinforcement	Wide-but-limited weave with edge pauses	Undercut at both toes; uneven leg length

Fill in thin layers rather than one thick pass. Each layer should be slightly convex and tied in at both walls, and total reinforcement should stay within the limits your WPS or code specifies.

Interpass Cleaning: The Step Everyone Skips

Remove all slag completely between passes. Chip it, wire-brush it, and grind the groove corners if any film survives. Trapped slag in those corners is the single most common defect in 3G test rejects, and it usually comes from a fill pass laid over an uncleaned root rather than from bad technique. A flashlight check of each layer before the next one starts takes five seconds and saves a gouge-and-remake later.

Run these steps in order on every joint: set the body and angles, choose stringer or weave for that pass, hold the edge pauses, clean to bare metal, then repeat. Consistency across layers, not a single heroic pass, is what makes a vertical-up weld pass visual and ultrasonic inspection.

Process-by-Process Settings: SMAW, GMAW, FCAW and GTAW Vertically

Good vertical technique only survives if the machine supports it. Once the plate goes upright the heat balance shifts: the arc heats a puddle that gravity is pulling down, while the metal above keeps soaking heat that has nowhere easy to go. Each process answers that differently, so here are starting-point settings for the four arc processes you are most likely to run vertical. Treat every value as a baseline to dial in on scrap of the same thickness, not a substitute for a qualified procedure. As The Fabricator’s training guidance on positioning explains, changing position shifts nearly every variable at once.

SMAW (Stick): Short Arc and Reduced Amperage

Stick is the most tolerant vertical process because the flux blanket carries the puddle. Drop amperage roughly 10 to 15 percent below your flat setting for the same electrode and thickness, keep arc length tight at about the electrode diameter, and listen to the arc. A soft, rolling hiss instead of a crisp crackle usually means the voltage is heating the plate faster than you can control it.

Progression follows the codes covered later: E6010 roots on open grooves are still frequently run vertical-down on pipeline work, while E7018 fill and cap passes almost always go vertical-up with stringers first. Why SMAW remains the fallback for field vertical work is covered in Advantages of Stick Welding: Why SMAW Still Wins. For a root-to-cap look at the position, Lincoln Electric’s master class on vertical-up welding is a worthwhile reference.

GMAW (MIG): Short-Circuit Transfer and Lower Voltage

Vertical-up MIG lives or dies on transfer mode. Spray transfer is too fluid to hold against gravity, so steel is welded vertical with short-circuit transfer, or pulsed transfer if the machine offers it. The single most useful change: for vertical-up, reduce voltage by 2 to 3 V at the same wire feed speed you would use flat. That keeps short-circuit frequency high and the puddle small enough to freeze between shorts.

Gun geometry matters as much as the numbers. Hold the wire nearly perpendicular to the joint. If porosity appears, which happens when the shielding envelope is disrupted by the joint edge or a draught, open the travel angle up to 20° past perpendicular in the direction of travel so gas still covers the solidifying bead behind the arc. Aluminum shrinks that margin dramatically; vertical aluminum work follows its own rules in Aluminum MIG Welding: The Complete Practical Guide.

FCAW: Stringers, a Slight Drag, and a Shake

Flux-cored wire lays down more slag than stick and behaves accordingly. Gas-shielded FCAW runs on DCEP with the argon/CO2 blend your wire manufacturer specifies; self-shielded FCAW runs on DCEN and tolerates draughts better but smokes harder. Vertical-up commonly uses stringer beads with a slight drag angle, and many welders add a small side-to-side shake of the gun at the top of each manipulation to flatten the face and pin the toes in. Bumping the arc-force or inductance setting helps the puddle wet without sagging. Chip and brush between passes: trapped slag under a cap is one of the most common reasons a visually fine weld gets rejected. Which classified consumables are genuinely rated for vertical positions is explained in All Position Welding Rod Guide: Types, Uses & Tips.

GTAW (TIG): Fade the Heat as You Climb

Vertical-up TIG has no flux to help and the most delicate heat input to manage, so it needs the most deliberate adjustment: a progressive 10 to 20 percent amperage reduction over the run, because heat accumulates in the joint faster than it dissipates. Ease off with the foot pedal as you climb, set a slope-out time on the machine, or break long runs into shorter segments with cooling between them. Dab the filler into the leading edge of the pool rather than into the arc, and keep the electrode pointed at the toes. On thin sections and critical assemblies that discipline tightens further, as Aerospace TIG Welding: Standards, Techniques, and Training makes clear.

Process	Progression	Main change vs flat	First thing to check
SMAW (7018)	Vertical-up stringers	10-15% less amperage	Arc length shorter than flat
GMAW (short-circuit)	Vertical-up	2-3 V lower at the same wire feed speed	Wire nearly perpendicular; open travel angle toward 20° past perpendicular if porosity appears
FCAW (gas-shielded)	Vertical-up stringers	Slight drag plus a flattening shake	Slag removed between passes
GTAW	Vertical-up	Progressive 10-20% amperage cut over the run	Filler dabbed at the pool front, not into the arc

Whichever process is in your hands, the physics does not change: vertical work wants less heat than flat, a shorter arc, and a steady, unhurried progression. Set conservatively, prove the settings on scrap, and let the puddle rather than the display make the final call. How these progression choices interact with qualification, codes and procedure paperwork is the subject of the next section.

Common Vertical Welding Defects and How to Fix Them

Vertical work is unforgiving because gravity keeps pulling on the puddle whether you are ready for it or not. Nearly every reject on a vertical pass traces back to seven problems: undercut, sagging or a convex bead, lack of fusion, slag inclusion, porosity, cold lap, and crater cracks. The good news is that each has a small, identifiable cause, and the fix is usually a tweak to pause timing, heat, or rod angle rather than a rebuilt joint.

Undercut at the Toe: The Classic Vertical Killer

Undercut is the groove melted into the base metal along the edge of the weld that the filler never filled back in. On vertical plate it shows up at the toes of the cap, where the arc washes the sidewall and moves on before the puddle can level out. There are really only two root causes: moving too fast, and dwelling badly at the edges.

The correction feels slow the first time you do it. Pause 0.5 to 1 second at each toe of the weave before stepping across the joint. That short dwell lets the filler wet into the corner and rebuild the edge profile so the transition is smooth instead of notched. If undercut persists after your timing is fixed, amperage is usually too high for the weave width, or the electrode is too large for the wall thickness. If you are unsure which consumables are honestly rated for this, our all-position welding rod guide breaks down which classifications actually earn the position.

Sagging and Convex Beads: When the Puddle Gets Too Hot

A bead that bulges, ripples at the bottom edge, or hangs proud of the joint is telling you the puddle was too fluid for the position. Sagging and a convex profile almost always come from excess heat: too much amperage, too high a voltage on a wire process, or travel so slow the deposit piles up instead of tying in.

• Drop amperage roughly 10 to 15 percent from your flat setting for the same rod.
• On wire processes, lower voltage before touching wire feed speed, and shorten stick-out.
• Keep travel steady; slow your weave frequency rather than crawling the whole bead.

Lack of Fusion: The Downhill Trap

Downhill progression moves the arc faster than the puddle can follow, and the melt overruns the arc instead of trailing it. Once the puddle gets ahead, the arc is heating metal in front of its own pool, so the bead lays onto relatively cold, un-fused surface and only appears tied in. This is the signature lack-of-fusion pattern of vertical-down work on anything thicker than light sheet, which is why most structural codes restrict downhill to thin material or root passes. If you suspect it, slow the travel slightly, add a slight weave to force sidewall wash, and switch to uphill once the joint exceeds the thickness your procedure allows.

Slag Inclusion

Slag gets trapped when a pass is laid over a poorly cleaned previous bead, or when a groove is too narrow and deep for the flux to float out. In vertical-up multi-pass work the risk climbs because each bead sits on an angled shelf. Chip and wire-brush every pass, keep the flux ahead of the puddle fluid and clearing to the sides, and widen the joint geometry slightly if your procedure permits. Never cap over a shiny, un-chipped pass because it “looks fine.”

Porosity

Gas pores usually trace to lost shielding, moisture in the coating, or contamination on the plate. Draft is the frequent culprit on site work: wind strips the shielding envelope from a stick or wire arc, and the welder’s vertical body position often puts the gas cylinder closer to the work than usual. Store low-hydrogen consumables dry, clean the joint, and shield the work area from drafts. Outdoors, self-shielded flux-core is far more tolerant than gas-shielded wire for exactly this reason.

Cold Lap (Overlap)

Cold lap is filler that froze onto the base metal without truly fusing, usually because the arc was too short, the travel too fast at the edges, or the amperage too low for the puddle size. Fix it by extending the pause at the toes, holding a tight but honest arc, and trimming weave width so the puddle never outruns the heat available to wet it in.

Crater Cracks

Craters at the stop end shrink faster than the surrounding metal, and the resulting tension pulls a star-shaped crack. Back up over the crater, pause to refill it, and on aluminum or high-strength alloy steels use a run-off tab or crater-fill technique. On startup cracks in alloy materials, preheat and hydrogen control on the consumable matter as much as the crater itself.

Run this checklist mentally after every vertical pass: are the toes filled, is the profile flat to slightly convex, does the root show tie-in on both sides, and is the surface clean enough for the next layer to wet in? Catching a defect between passes costs a minute of chip-and-grind work; catching it after the cap costs the whole weld.

Qualification, Codes and WPS: Welding Vertically to Standard

Technique gets you a sound bead, but paperwork gets it accepted. On any structural or pipeline job the real question is never just “is it welded?” but “is it welded to a documented, qualified procedure, by a welder certified for that position?” Here is how 3G and 4G qualification, WPS documents and code rules actually treat vertical work.

What 3G and 4G Qualification Actually Proves

In AWS terms the “G” in 3G and 4G stands for groove weld, and the number describes plate position: 3 is vertical, 4 is overhead. A 3G groove test means welding a groove joint in a plate standing vertical; a 4G test is a horizontal groove in a plate lying overhead above you. Fillet equivalents exist too: 3F is a vertical fillet on a Tee joint, 4F an overhead fillet.

Under AWS D1.1 groove welder qualification practice, welders generally qualify for vertical groove work by welding a 3G coupon in the upward progression. Passing 3G uphill typically earns broader qualification ranges than a fillet-only 3F, because a single 3G coupon can qualify a welder for flat, horizontal and vertical production groove welding within stated thickness ranges: it exposes the welder to the toughest solidification control. Overhead adds 4G if the job requires it.

What a WPS Must Specify

A Welding Procedure Specification is the recipe. Before a welder tests, the shop works from a WPS supported by a Procedure Qualification Record (PQR) documenting a test weld actually made and tested to destruction or NDE. For vertical work, a complete WPS specifies at minimum:

• Welding process or processes (SMAW, GMAW, FCAW, GTAW)
• Joint design and preparation: root opening, land, included angle
• Filler metal classification and diameter, such as E7018 for a vertical-up root and fill
• Polarity, current range, voltage and travel speed
• Gas composition and flow rate for open-arc processes
• Preheat and interpass temperature limits
• Bead placement, pass sequence, and whether progression is vertical-up or vertical-down
• Required cleaning, and any PWHT where the code calls for it

The progression direction matters most: a welder qualified for vertical-up is not automatically qualified for vertical-down on the same coupon range under D1.1, and the reverse is equally true.

How D1.1, API 1104 and ASME Section IX Differ

AWS D1.1 governs structural steel. Groove welder qualification is commonly achieved through a 3G or 4G plate test, with the vertical test performed uphill. Qualification ranges for plate thickness apply, and production work must stay inside the position range the test earned.

API 1104 is the pipeline world’s standard, covering arc welding of butt, branch and fillet welds in pipe. It is used alongside ASME B31.4 (liquid pipelines) and ASME B31.8 (gas pipelines) for acceptance criteria. The published API 1104 PDF details welder qualification test positions for pipe, including vertical fixed pipe (5G) and vertical fixed with rotation (6G) coupons that combine vertical, horizontal and overhead in one test. DOT pipeline safety regulations reference these standards, as seen in federal materials such as the published DOT document.

ASME Section IX, the pressure vessel and boiler code’s qualification rulebook, defines positions through QG-109 through QG-112 designations (1G through 6G) and permits a welder qualified on a 3G coupon to weld vertical positions. Section IX also treats production positions as a continuum rather than a discrete list. That is the key point: if a plate or pipe axis deviates from true vertical by more than 20 degrees under Section IX (or the ±15-degree tolerance AWS allows on test coupon positioning), the work may legally no longer count as the vertical position at all.

Reading Qualification Ranges Without Getting Burned

Every qualification record carries ranges: base metal group, thickness, process, positions and progression. A welder who tested on 12mm plate with E7018 uphill is qualified for vertical groove welding within the thickness band the code assigns to that coupon, using electrodes in the same classification family. Swap to a different all-position rod classification outside the WPS, and the qualification no longer covers the work.

The most common rejection on real jobs is not a bad weld. It is a welder running outside their qualified range: wrong progression, wrong process, wrong thickness, or a job angle that slipped past the position tolerance. Check the range before you strike the arc, and the code becomes an ally rather than a hurdle.

Safety, Fumes and Ergonomics in Vertical Welding

Vertical work tops the difficulty curve and the hazard curve. The puddle fights gravity, your arms fight it too, and the plume you chase upward carries metal fumes into your breathing zone. Fatigue is not just discomfort in a vertical weld; it is a defect generator and a safety risk. This section covers the gear, ventilation and body mechanics that keep vertical welders productive.

Personal Protective Equipment: More Than a Helmet

At minimum, vertical arc welding demands an auto-darkening helmet with the right shade, safety glasses under the helmet, flame-resistant jacket and sleeves, leather gloves and steel-toed boots. Add a respirator for overhead-leaning vertical joints, because the plume rises toward your face. A half-mask with P100 particulate filters is the baseline; welding coated or plated stock may call for supplied-air protection.

Vertical work adds two concerns flat welding rarely raises. Spatter and molten slag fall differently when you run uphill along a joint, so a full collar or cape protects your neck. Grinding and chipping between passes at height send debris past your face and torso, so face shields and arm protection become essential. Consumables matter too: stick and flux-cored wires vary considerably in fume generation, so knowing the electrode you run, covered in our guide to alloy steel welding electrodes and their safety considerations, helps you match PPE to the hazard.

Welding Fumes: What the Evidence Says

Welding fume is a complex aerosol of metal oxides, silicates and gases, formed when flux, base metal and shielding gas are heated past their boiling points. NIOSH’s criteria document 88-110 concluded that welders have roughly a 40% increase in relative risk of lung cancer, and OSHA’s welding safety fact sheet warns that prolonged exposure may cause lung damage and cancers of the lung, larynx and urinary tract. In the UK, the Health and Safety Executive estimates metal fume exposure hospitalises 40 to 50 welders each year, largely from metal fume fever caused by inhaling zinc or copper oxide fumes. Canada’s federal welding safety guide reinforces the same hierarchy of controls.

Ventilation and Confined Spaces

The governing standard for construction welding is OSHA 1926.353, which requires ventilation and personal protection during welding, cutting and brazing. Where local exhaust ventilation controls fumes, the standard specifies at least 2,000 cubic feet per minute per welder, adjusted so the airflow effectively captures the plume. General dilution ventilation alone often falls short for vertical and overhead work, where fumes rise into the welder’s face, so a properly positioned fume extractor arm earns its cost.

Vertical welding inside tanks, vessels or pits is where risk escalates. Confined spaces require a written permit, atmospheric testing for oxygen, flammable gases and toxic contaminants, forced ventilation, a standby attendant and rescue plans. Welds in such spaces often produce heavier fume concentrations, because heat drives gases upward with nowhere to escape. Fabricating structural or pressure work adds code requirements, a point we develop in Alloy 20 welding procedures and best practices, where exotic base metals make fume control even more critical.

Ergonomics: The Injury Nobody Talks About

Holding a stinger overhead-leaning for a vertical-up root pass loads shoulders, neck and lower back in ways flat welding never does. Sustained static contraction restricts blood flow, and the resulting fatigue degrades arc control, raising defect rates and burns when your arm gives out. The Fabricator’s guidance on positioning emphasises setting up fixtures, elevators and adjustable platforms so the joint sits between waist and shoulder height.

Habits that pay off over long vertical runs:

• Bracing your welding hand against the work with a free finger or magnetic rest to offload shoulder strain.
• Rotating between vertical-up root work and easier flat passes instead of grinding through a full day in one position.
• Keeping your head and torso squared to the joint instead of craning your neck to watch the puddle.
• Breaking vertical runs into manageable pass lengths, cleaning and stretching between them.

Long vertical runs add heat stress. Welding supply partners who take gas and equipment safety seriously, such as the operators profiled in our AllGas welding supply safety guide, can help shops spec the extraction and shielding setups these jobs need.

A Vertical Welding Safety Checklist

Before you strike an arc on a vertical joint, check: helmet shade and respirator fit, fume extractor positioned above and ahead of the joint, overhead work clear of personnel, fall protection if you are on an elevated platform, and footing solid enough to move with the puddle. You cannot weld precisely while choking on fume or shaking out with a tired shoulder, so treat the safety setup as part of your technique.

Practical Practice Plan, Common Mistakes and Conclusion

Knowing the theory of vertical arc welding and holding a sound bead are two different things. The gap closes only with deliberate, staged practice. The plan below takes you from your first vertical pass to a coupon you would be willing to hand to an inspector.

A Four-Stage Practice Plan

Stage 1: Stringers on flat plate. Start on 1/4 in (6 mm) plate with E7018 stringer beads run vertical-up. No weaving, no gap, no pressure to look good. Set amperage roughly 10–15% below what you would use flat for the same rod, keep a short arc, and focus on one thing only: consistent travel speed and a pause long enough to wet the toes without letting the puddle sag. Run 50 mm beads, chipping and brushing between every single one, and look at the result while it is still warm. If the bead is convex and narrow, you are moving too fast or amperage is too low; if it is flat and wide with bruised edges, you have too much heat or too long an arc. This stage is where your all-position welding rod habits get built, so choose consumables rated for vertical work from the start.

Stage 2: Root, fill and cap coupons. Move to a 3/8 in V-groove with the land and root opening your target code calls for. Run the root hot and narrow, then a fill pass, then a cap that stays inside the bevel. Treat each pass as a separate exercise: strike an arc, finish the pass, cool, clean, inspect. Only when each layer is defect-free on its own should you link them together. Three clean coupons in a row tell you more than one excellent one.

Stage 3: Jointed work. Tack and weld actual T-joints and full-penetration plates in position, including a fit-up that is not perfect. Real structures rarely give you even gaps, and learning to compensate with travel speed rather than excessive weave width is a skill that only comes from awkward joints.

Stage 4: Repetition under time. Once the beads are consistently acceptable, add pace. Run the same coupon repeatedly and chart your time per pass alongside your reject rate. Speed is a by-product of consistency, not a substitute for it. If you are considering formal training, a structured aluminium welding course style curriculum, even studied as a syllabus, shows how instructors sequence these drills.

Beginner Mistakes That Guarantee Rejection

Most vertical rejects are not exotic. They come from the same handful of errors:

• Too much heat. Beginners crank amperage to compensate for a shaky hand, which thins the toes and invites undercut.
• Travel that is too fast. The arc arrives before the puddle can support itself, producing cold, poorly fused beads.
• An arc that is too long. On 3G work especially, a long arc loses shielding, spreads heat and leaves an erratic, oxidised puddle.
• Weaving wider than the joint allows. A weave that runs past the bevel edges overheats the base metal and guarantees undercut at the toes.
• Skipping slag removal. Trapped flux between layers becomes a slag inclusion that only shows up after X-ray.
• Running back-to-back passes on red-hot plate. Consecutive passes on cherry-red steel push heat into the joint and distort the bead profile.

The Pre-Arc Checklist

1. Confirm the WPS range: electrode class, diameter, polarity and amperage window.
2. Verify position tolerance, since AWS test positions allow roughly ±15° of inclination.
3. Grind and brush the joint; remove mill scale, oil and moisture from the fusion faces.
4. Bake or hold low-hydrogen rods in a rod oven if they have been exposed.
5. Set amperage 10–15% below flat values and shorten the arc before you strike.
6. Plan your start, restart and crater point, and stage your chipping hammer and wire brush within reach.
7. Check ventilation, helmet shade and fume extraction are actually running.

The pattern behind every item is the same, and it is the pattern the whole article has circled back to: control beats power. Vertical arc welding punishes haste. Reduce amperage slightly, keep the arc short, pause at each toe, weave only as wide as the joint permits, clean between every pass, and let the plate cool before the next layer. Do that consistently and the position stops being the test that separates hobbyists from structural welders, and simply becomes the next joint on the schedule.

As welding training specialists emphasize, positioning and preparation decide the outcome long before arc time does, and vertical welding practice guides repeat the same core advice for a reason: the fundamentals work. Put in the staged repetitions, log your rejects, fix one variable at a time, and the 3G cap that once failed on undercut will start passing without drama.

Frequently Asked Questions

What is vertical arc welding?

Vertical arc welding is arc welding in which the weld joint axis runs up and down, so the welder must deposit metal either upward or downward against gravity. It covers groove (3G) and fillet (3F) joints on plate, as well as vertical seams on pipe and tanks.

Should I weld vertical up or vertical down?

As a general rule, weld vertical up on material thicker than about 1/4 inch (6 mm) because it gives deeper penetration and better puddle control. Vertical down is favored for thin sheet under 1/4 inch and for pipeline root and hot passes with cellulosic electrodes, and many structural codes prohibit downhill on plate.

Which electrode is best for vertical welding?

E7018 low-hydrogen stick electrodes are the standard choice for vertical-up structural work because their thick, fast-freezing slag supports the puddle. E6010 and E6011 cellulosic rods suit vertical-down and open-root pipe work, while E6013 works in either direction on light sheet.

What angle should I hold the electrode when welding vertical?

Keep the work angle at about 90 degrees for butt joints and 45 degrees for tee joints, with a travel angle of roughly 5 to 15 degrees pointing uphill. For downhill, increase the travel angle to 15 to 30 degrees so the arc pushes back and holds the puddle in place.

Why is my vertical weld sagging or dripping?

Sagging means too much heat input: amperage or voltage too high, travel too slow, arc too long, or a weave that is too wide. Reduce amperage by about 10-15% from flat, shorten the arc, narrow the weave and travel slightly faster so the puddle stays stiff.

How do I stop undercut on a vertical cap pass?

Undercut appears when you rush past the toes. Pause about half a second to a full second at each edge of the groove to let weld metal fill the crater, then move briskly across the center where the puddle is already hottest.

What is the 3G weld test?

The 3G test is a vertical plate groove weld qualification coupon, typically welded uphill with root, fill and pass capping, used under codes such as AWS D1.1 to qualify a welder for vertical groove welding. Passing 3G generally expands your qualification range to include flatter positions.

Is vertical welding harder on the body?

Yes. Vertical work often forces awkward arm elevation and neck extension for long stretches, which causes shoulder and neck fatigue, and vertical progress keeps the fume plume close to the breathing zone. Positioning, local exhaust ventilation and planned breaks reduce the strain.