3G Position Welding: The Complete Guide to Vertical Plate Welds

A welder walks into a structural shop for an interview, résumé in hand, and the foreman asks one question: “Can you run vertical?” That single word decides whether the applicant gets hired at full rate or sent home. Vertical plate welding — the 3G position — is the test that separates welders who can only lay flat beads from those trusted on the joints that hold buildings and bridges together.

What 3G Position Welding Really Means

A welder walks into a structural shop for an interview, résumé in hand, and the foreman asks one question: “Can you run vertical?” That single word decides whether the applicant gets hired at full rate or sent home. Vertical plate welding — the 3G position — is the test that separates welders who can only lay flat beads from those trusted on the joints that hold buildings and bridges together.

So let’s answer the principal question right away. 3G position welding is a groove weld made on plate that stands upright, with the weld progressing from the bottom upward. In AWS terminology the numeral designates the welding position and the letter designates the type of joint: G stands for groove weld, while F stands for fillet weld. Put them together and 3G literally reads “third position, groove.” The official definitions behind that numbering come from AWS A3.0, the standard welding terminology and definitions document used across the industry.

Decoding the AWS Position Numbering

The system is simpler than it looks, and once it clicks you can read any weld test coupon description on sight:

• The number tells you where the work sits relative to the welder: 1 is flat, 2 is horizontal, 3 is vertical, 4 is overhead.
• The letter tells you the joint geometry: G for a groove weld (a butt or similar joint welded through the thickness), F for a fillet weld (a T-joint, lap, or corner).

So a 3G coupon is a butt joint in plate set on end like a wall, with the weld axis running vertically. In practice the welder stands in front of an upright plate and progresses uphill, fighting gravity on every pass. Molten metal wants to drip, sag, and pile; the arc wants to ride ahead of the puddle. Every technique decision in a 3G weld exists to counteract those forces.

Why the 3G Position Matters

Structural steel does not arrive at the job site already flat. Column splices, beam-to-column connections, gusset plates, bridge members, and heavy equipment frames all end up in positions where the welder is looking at a vertical joint — often in a shop, frequently in the field. Flat welding is what beginners learn first; vertical groove welding is what production work actually demands.

Because gravity works against fusion in this position, 3G is one of the two most demanding plate positions, alongside 4G overhead. It is also the most commonly required structural plate qualification for fabrication and construction work in the United States. When a shop advertises for a “certified” structural welder, the qualification they usually mean is a vertical groove test — commonly run under SMAW with E7018 electrodes, though GMAW vertical-up and FCAW vertical-up versions are common too.

Passing a 3G test signals something specific to an employer: this welder can control a puddle that is constantly trying to run away, read their own bead, and produce sound metal in the position where defects are most likely to form. As AWS Welding Digest has noted, weld testing is the practical, hands-on proof of ability that employers rely on when résumés all look the same.

What This Guide Covers

This article walks the full 3G path, start to finish:

1. The complete plate position system — 1G through 4G, the F positions, and how 3G compares to 5G and 6G pipe work.
2. How a 3G qualification coupon is actually built under AWS D1.1: fit-up, groove angle, root opening, backing, and preheat.
3. Vertical-up versus vertical-down, and what the code actually permits.
4. Pass-by-pass technique for SMAW, GMAW, and FCAW — root, fill, and cap.
5. The defects that get welders rejected and how to fix each one before the inspector finds it.
6. Visual inspection, guided bend testing, and acceptance criteria.
7. Exactly what a 3G qualification covers, and the positions it does not.
8. Safety, fume control, and ergonomics specific to welding uphill.
9. A practical preparation plan for passing the test the first time.

By the end, you should be able to read a welder qualification table, understand what a 3G stamp on a performance record means, and walk into a test bay knowing what the coupon requires before you ever strike an arc.

Understanding the Welding Position System: 1G, 2G, 3G, 4G and the F Positions

A test sheet rarely says “vertical weld on plate.” It says 3G. That two-character code is shorthand from a system that welders, inspectors, procedure writers and employers all share, and once it clicks you can read a job posting or a qualification record as easily as a pilot reads a runway. AWS codifies this vocabulary in AWS A3.0, Standard Welding Terms and Definitions, and the grammar is simple: the number describes the position, and the letter describes the type of weld. G stands for groove, F stands for fillet. Before we go deeper into vertical plate welding, it pays to understand the whole map and see exactly where 3G sits on it.

The Groove Weld Positions: 1G Through 4G

Groove welds are the butt-style joints where two plates meet edge to edge and the weld metal fills a prepared gap. AWS recognizes four groove positions on plate:

• 1G (flat). The plate lies flat, the weld is made on the top surface, and the weld axis runs horizontally. The puddle pools down into the joint with gravity working for you. This is the easiest position in the book, which is why production shops run most of their work in flat and beginners learn 1G first.
• 2G (horizontal). The plate stands upright on its edge, but the weld axis still runs horizontally. Gravity is no longer holding the puddle in the joint; it is pulling the puddle down out of it. A 2G groove test qualifies a welder for flat and horizontal groove welding, covering a lot of shop work in a single test.
• 3G (vertical). The plate is upright again, but now the weld axis runs vertically and the welder normally progresses bottom-up. Everything that made 1G forgiving now works against you. This is the position the rest of this article is about, and the one that makes or breaks structural welder interviews.
• 4G (overhead). The plate is held horizontal above the welder’s head, and welding is done from below. The puddle hangs overhead and wants to drip onto your hood. What catches candidates off guard is the coverage: a 4G plate test qualifies a welder for flat, horizontal and overhead groove welding, but it does not cover vertical.

Position	Plate orientation	Weld axis	Character of the weld
1G	Flat	Horizontal	Easiest; gravity helps the puddle settle into the joint
2G	Vertical, on edge	Horizontal	Qualifies flat and horizontal groove welding
3G	Vertical	Vertical, usually uphill	Gravity works against puddle control
4G	Horizontal, above welder	Horizontal	Overhead; welding done from below

The Fillet Positions: 1F Through 4F

Fillet welds join two pieces at an angle rather than edge to edge: T-joints, lap joints, and corner joints. They use the same numbering logic with an F instead of a G: 1F flat, 2F horizontal, 3F vertical, and 4F overhead. Because a fillet has no groove walls to fuse against, fillets are generally more forgiving than grooves in the same position, and a 3F is easier than a 3G for most welders. That is one reason plate groove tests carry extra weight on a résumé: passing 3G usually pulls fillet qualifications along with it, while the reverse is not true.

Pipe Positions: 5G and 6G for Contrast

Pipe adds its own categories. In 5G, the pipe is fixed horizontally and cannot be rotated, so the welder travels around the circumference through flat, vertical and overhead sections in a single sequence. In 6G, the pipe is fixed at a 45-degree angle, stacking every challenge onto one coupon. The 6G test has a reputation as a universal ticket and is the most demanding common single test, but plate coverage is not automatic with it. As the qualification guidance in Portland Community College’s welding qualification and certification handbook lays out, exact ranges depend on the governing code and its tables, so always confirm coverage rather than assuming it.

Why the Numbers Climb With Difficulty

The pattern in the table is not accidental. Each step up the ladder removes a little more help from gravity. In 1G the puddle sits down in the joint; in 2G it has to cling to the side; in 3G it has to be carried upward against its own weight; in 4G it has to be kept from raining down on you. Ergonomics compound the difficulty: vertical and overhead work means sustained raised arms, a tilted neck, and fine motor control in a position your body is fighting. Heat management gets harder too, because in vertical and overhead the puddle solidifies faster and has less time to wet into the joint before it freezes.

That is exactly why employers advertise for “all-position” welders and often pay a premium for them. One welder qualified on 1G through 4G plus the fillet positions can be assigned anywhere in the shop or on the erection site. In the field, structural steel never conveniently presents itself in flat: columns, beams, gussets and bracing all force vertical and overhead joints. The AWS Welding Digest’s guidance on passing a weld test keeps returning to the same point: know which positions the test actually covers before you strike an arc, because candidates routinely study the wrong coupon.

With the map in hand, you can see where 3G really sits. It is not an exotic specialty; it is the middle rung where gravity stops helping and starts testing you, and it is the qualification that most often decides whether a structural shop hires you at full rate. From here, we will build the 3G test coupon itself, then look at how the vertical-up technique actually runs, starting with the 3G SMAW test with E7018 electrodes.

The 3G Test Coupon: Fit-Up, Geometry and Joint Preparation

Open any certification bay and the scene is identical: two plates clamped upright in a stand, a protractor on the bench, and a welder running a finger along the groove before anyone strikes an arc. Most 3G rejections trace back to this moment, not to the arc itself. Technique gets the practice time, but the coupon decides the test. When the fit-up is wrong, no amount of puddle control recovers the bend specimens.

A 3G qualification coupon is the joint you weld to prove you can run a vertical groove weld in plate: the plate stands upright, the weld axis runs vertically, and progress is uphill. None of its geometry is improvised. AWS publishes the standard terminology for every dimension you will read on the drawing, from root opening to groove angle, in AWS A3.0, Standard Welding Terms and Definitions, while the dimensional recipe itself comes from the governing procedure.

The Groove Geometry, Dimension by Dimension

The classic backed 3G coupon is a single-V groove: both plate edges beveled so the finished joint opens at a 45-degree included groove angle, which works out to 22.5 degrees per side. Cut the bevels with a bevel-burning guide or a mill, then check them with a protractor. A couple of degrees of error on each side changes how far the arc can reach the root, and the root pass is where candidates lose coupons. Keep the bevel faces smooth and free of gouges from the cutting arc as well; a ragged face gives slag a place to hide and gives the tie-in an unpredictable landing.

Dimension	Typical 3G value	Why it matters
Plate thickness	3/8 in (10 mm) standard test plate	Drives the thickness range you qualify for
Included groove angle	45° total (22.5° per side)	Gives the electrode access to the root
Root opening	1/4 in (6 mm) with backing	Controls penetration and burn-through risk
Root face (land)	Small, commonly about 1/16 in	Too heavy and you get lack of fusion
Backing bar	Min 1/4 in (6 mm), max 3/8 in (10 mm)	Supports the molten pool uphill
Preheat / interpass	32°F (0°C) minimum on 3/8 in plate	Prevents cold-cracking and unstable arcs

The most reliable field trick for the root opening is also the oldest: a typical root opening with a backing bar is 1/4 in, and welders commonly set it by slipping two 1/8 in electrodes into the gap as spacers before tacking. Check the gap at both ends and the middle. A root that drifts from 3/16 in to 5/16 in halfway up the plate is a coupon welded under two different procedures. Most specifications allow only a hair of tolerance around the specified opening, so measure, correct, and then tack, rather than tacking first and hoping the plates cooperate.

Backing Bar, Tacking and Heat Control

Backing bar thickness for the 3/8 in plate configuration ranges from a minimum of 1/4 in (6 mm) to a maximum of 3/8 in (10 mm). Fit it flush against the root faces, clamp or tack it square, and make sure it is clean and free of mill scale and oil. Tacks should be made with filler metal and parameters consistent with the procedure, placed where they will not interrupt your test length, and finished flush if they sit in the weld zone. A proud tack at the start of your root pass is a guaranteed cold lap. Check the back side before you start, too: backing that sits gapped lets the root drop through and creates a concave underside the bend test will expose immediately.

Heat is the quiet variable. For 3/8 in plate, the minimum preheat and interpass temperature is 32°F (0°C); if the base metal is below 32°F, it must be preheated to at least 70°F (20°C). In a cold shop this is not optional, and “cold” includes a plate that has been sitting against a concrete floor all morning. Measure with a contact thermometer or heat stick, not the back of your hand, and recheck between passes because a vertical plate sheds heat unevenly, losing it fastest through the thin edges you just heated.

Unlimited vs. Limited Thickness Qualification

Coupon thickness is a strategic choice. Under AWS D1.1 welder qualification practice, running the test on 3/8 in plate with backing is the standard route to an unlimited-thickness groove qualification, while thinner coupons earn a narrower band tied to the coupon itself. The exact ranges live in the D1.1 base metal thickness table, so confirm the current edition rather than trusting a shop’s laminated wall copy. If your résumé says “3G unlimited,” the person checking it will ask which coupon produced that statement.

Why Fit-Up Consistency Wins the Test

Fit-up controls arc behavior before you ever light up. A wide root invites sag and blow-through; a tight root traps slag and leaves the root unfused. Uneven bevels force you to chase the puddle sideways instead of stacking beads on top of each other.

That is why experienced candidates treat fit-up as part of the weld, as described in practical guides like gowelding.org’s 3G SMAW setup walkthrough: square the plate, verify angle and gap at three points, confirm backing contact, clean the joint, verify preheat, then run a written pre-weld checklist. Do that and by the time the inspector checks your coupon with a rule, the numbers agree with the paperwork. Skip it and you will be troubleshooting your technique for a problem the geometry created.

Vertical-Up vs Vertical-Down: What the Code Actually Permits

Ask ten apprentice welders whether you’re allowed to run vertical downhill and you’ll get ten different answers. Some swear every structural weld must go uphill. Others learned to burn downhill in a shop and assume it carries anywhere. The truth sits in the fine print of AWS D1.1, and it’s more specific than either camp thinks.

Upward Progression Is the Default

Under AWS welding terminology standards and the D1.1 Structural Welding Code, upward progression is the baseline for vertical position welding. For groove welds in plate, every pass — root, fill and cap — is expected to progress vertically uphill unless the procedure specification says otherwise. Gravity works against a downhill puddle: it pulls molten metal ahead of the arc, so the weld freezes on top of unfused material instead of tying into it.

Uphill is slower. There’s no way around that. But the slower travel produces a more consolidated weld with complete fusion, a fully tied-in root, and a profile the inspector can accept without grinding. That is why certification tests, from the standard 3G SMAW plate test through the 3G GMAW vertical-up test, are built around uphill progression from the first bead.

Direction Is an Essential Variable

Here is the point candidates get burned on: in AWS D1.1, changing direction of vertical progression — uphill to downhill or vice versa — is an essential variable. It applies to both the welding procedure specification (WPS) and welder performance qualification.

What that means in plain language:

• A welder qualified on a vertical-up plate coupon is qualified to weld vertical-up. That single test does not buy both directions.
• A WPS qualified for upward progression cannot simply be run downhill in production. Reversing direction invalidates the procedure, and the fabricator must qualify a new one.
• Essential variables are the parameters the code treats as mechanically significant. Change one, and the previous qualification no longer covers the work.

The One Narrow Downhill Allowance

D1.1 does contain a specific exception for vertical downward welding: repairing undercut. You may run downhill to fill and blend undercut, and only when the applicable preheat requirements are satisfied. That’s it — a targeted repair allowance, not a green light for production downhill passes.

Downhill is legitimately used elsewhere, just not as the default for a structural vertical groove:

• Fillet welds and flare-groove welds — vertical-down is commonly permitted and frequently specified for these joint types.
• Short-circuit GMAW on thin material — the controlled, low-heat transfer of short-circuit mode lets welders run downhill on sheet without burning through.
• Undercut repair — as noted above, subject to preheat.

A downhill production procedure for any of these must still be qualified on its own. Direction is an essential variable regardless of how convenient the technique is.

Why Downhill Fails on Heavy Plate

The physics are unforgiving. Traveling downhill, the arc races ahead of the puddle, so the leading edge of the weld pool freezes before the base metal at the toe reaches fusion temperature. The result is predictable:

Factor	Vertical-Up	Vertical-Down
Travel speed	Slower	Faster
Penetration and root fusion	Deep, complete	Shallow, inconsistent
Common defects	Grinding, trapped slag between passes	Cold lap, incomplete fusion, slag entrapment at the toes
Typical use	Structural groove welds, all test coupons	Fillets, flare grooves, thin-sheet short-circuit, undercut repair

Cold lap at the toes is the classic downhill failure: the weld metal sits on the surface rather than biting in, and the inspector finds it with a file before the bend specimen is ever cut.

The practical takeaway: treat vertical-up as the working default for structural plate, understand that one direction doesn’t qualify the other, and check the procedure before you strike an arc in a direction you weren’t tested in.

Running the Passes: Root, Fill and Cap Technique for 3G

The 3G test is not won by strength; it is won by pass control. In vertical-up the puddle sits on a small shelf of its own making, and your job is to keep the arc buried underneath it, moving slowly enough to fuse both sidewalls but fast enough that the metal never sags out of the groove. The standard terminology used on qualification paperwork is defined in AWS A3.0, Standard Welding Terms and Definitions, so read your procedure with those definitions in front of you rather than from memory.

Three processes show up on 3G tests: shielded metal arc (stick), gas metal arc (MIG), and flux cored arc. Each has its own rhythm, but the geometry of the movement is shared across all three.

SMAW with E7018: The Workhorse of the Test

For an E7018 vertical-up bead, hold the electrode nearly perpendicular to the plate face and tilt it only enough to trail the arc behind the puddle, roughly a 5 to 15 degree uphill travel angle from perpendicular. Lean too far and the arc points ahead of the puddle, eating a crater into cold base metal. Too little tilt and you stack filler on top of an unfused root.

• Root pass: keyhole control. Tight arc, let the keyhole open about the width of the rod core, and stitch it closed with tiny side-to-side motions rather than a wide weave.
• Fill passes: a shallow triangle or J-weave, pausing a beat at each sidewall so the puddle wets in, then moving briskly across the middle.
• Cap: stringers or a narrow weave that stops short of the plate edges, leaving a clean tie-in without undercut.

The practical walk-through at Go Welding’s 3G SMAW guide lines up with what inspectors reward: a flat to slightly convex profile, no trapped slag, and edges that blend into the base metal without a cold lap.

GMAW (MIG): Vertical-Up Gun Control

Vertical-up MIG punishes a hot, runny puddle instantly, so start conservative. A commonly cited starting point for a vertical-up plate test is about 21.6 volts and 155 amps, with wire feed near 340 ipm and shielding gas flow around 25 CFH, as listed in the 3G MIG vertical-up procedure. Hold the gun at that same 5 to 15 degree uphill angle, keep your contact-tip-to-work distance consistent from pass to pass, and judge the settings by the bead shape: flat to slightly crowned is correct, shiny and bulging means too hot. If the wire starts stubbing or the arc stutters, your stick-out and gun angle changed before your voltage did.

FCAW: A Slow Root and a Steady Fill

Flux core rewards patience more than any other process on this coupon. For 0.045 in. wire, the vertical-up root travels slowly, around 4 to 7 IPM, while overall vertical-up travel settles near 8 to 12 IPM as the groove fills and stored heat builds in the plate, according to the 3G vertical flux cored procedure. Chip and wire-brush every pass. Flux-cored slag hides lack of fusion beautifully, and an inspector with a hammer will find what you missed.

Arc Length, Travel Speed and Weave Width

Arc length should stay tight and roughly equal to the electrode or wire diameter; dragging a long arc in the vertical position pushes heat upward and leaves the root cold. Travel speed is a feel thing, but the symptom is easy to read: a puddle that keeps growing and drooping means slow down on heat input, not speed up. A puddle that won’t stay put or keeps freezing ahead of the arc means you are moving too fast or too cold.

Weave patterns in 3G are usually a triangle, a J, a chevron, or plain stringers. The width limit keeps candidates out of trouble: keep fill-pass weaves to about three times the electrode diameter, pausing briefly at each sidewall for tie-in and moving quickly through the center. Go wider and the puddle outruns the arc at the edges, giving you cold-lap corners and a mushroomed cap.

Cleaning, Staggering and Interpass Control

Brush every bead, knock slag out of the sidewall corners, and stagger your starts and stops by half an inch to an inch so you never restart directly on top of a crater. Check interpass temperature against the procedure with a temp stick or infrared thermometer. Keep the plate between passes as clean as it was before the first arc, because that is where slag inclusions come from.

Common 3G Defects and How to Troubleshoot Them

Almost every 3G test rejection traces back to a short list of familiar defects, each with a vertical-specific cause and a concrete fix. Spot them in your own work between passes and you’ll correct them long before the inspector’s hands are on the coupon.

Incomplete Fusion: The Number One 3G Killer

Lack of fusion is the most common qualification failure on 3G coupons, full stop. The vertical-up position creates the exact conditions for it: the arc naturally rides ahead of the puddle, pointed uphill into cold, unfused base metal. The arc melts bare plate, the puddle trails behind and freezes against it, and you get a bead that looks acceptable but is only sitting on top of the joint rather than tied into it. Slower travel alone doesn’t fix it — you have to direct the arc back into the puddle and the joint walls. Drop your electrode or gun angle to roughly 5 to 15 degrees past perpendicular so the arc points slightly downhill, shorten your arc length, and pause deliberately at each side of your weave so the puddle wets into the bevel face before you swing across. A slight side-to-side dwell at the toes does more for fusion than any change in amperage.

Porosity and Trapped Slag

Porosity in vertical work usually comes from three sources: excessive arc length as the rod burns down and your hand drifts, moisture or contamination on the electrode or plate, and shielding gas disrupted by drafts or, in FCAW, by swinging your weave too wide and blowing the gas envelope sideways. Keep arc length tight, clean the land before every pass, and store low-hydrogen electrodes in a holding oven until the moment you need them.

Slag inclusion is the FCAW specialist’s nemesis. Trapped flux-core slag between passes is the single most common defect in vertical flux-cored work, and it hides at the toes and tie-ins, where a stringer bead covers a ridge of slag and the next pass traps it forever. The fix is unglamorous and non-negotiable: chip aggressively, run a knotted wire wheel along every toe and tie-in, and inspect before laying the next pass. If in doubt, chip it again.

Incomplete Penetration, Undercut, and Profile Problems

Incomplete penetration on a backed coupon usually means your root pass lacked the heat or travel speed to fuse the backing bar. Speed up slightly at the root or nudge amperage up within WPS range. Undercut, by contrast, comes from lingering too long at the edges of a weave while the puddle has drained away, gouging a groove along the bevel face that never refills. Slow your weave, shorten the side dwell, and let the puddle fill behind you.

The other profile defects are self-inflicted: excessive reinforcement from stacking too much filler too slowly, and underfill from the opposite. Both disappear when you maintain a consistent puddle size and read your bead profile between passes rather than after the cap.

Cracking

Cracks show up as crater cracks at stops, toe cracks from excessive restraint, or centerline cracks from a too-narrow, too-fast cap. Always fill your crater by pausing at the stop and stepping back into the puddle, stagger your starts and stops away from previous ones, and keep interpass temperature under control so you aren’t welding onto a plate that has become a heat sink. Any crack in the weld or HAZ is disqualifying, so stop and correct it the moment you see one — grinding it out mid-test is legal and smart; hoping it’s cosmetic is not.

Read Your Weld Before the Inspector Does

Quick 3G defect troubleshooting

Defect	Usual vertical-specific cause	Fix
Incomplete fusion	Arc riding ahead of the puddle	Arc back into the puddle, dwell at toes, short arc
Porosity	Long arc, wet electrodes, drafts	Tight arc, oven-stored rods, shield the work
Slag inclusion	Un-chipped slag at toes and tie-ins	Chip and wire-wheel every pass, no exceptions
Incomplete penetration	Root too cold or too fast	Fuse backing, adjust speed or amperage
Undercut	Puddle drained at weave edges	Shorten dwell, slow weave, let puddle fill
Crater cracking	Stop made on an unfilled crater	Back-step into the puddle, fill every crater

Build the habit of pausing after every pass: chip it, brush it, look at the toes, check for pinholes, and decide whether the next pass has something solid to bond to. Test-day guidance from AWS Welding Digest’s test-prep guidance and the process walk-throughs at GoWelding.org’s 3G SMAW guide, their 3G MIG vertical-up guide, and their 3G vertical FCAW guide all converge on one point: the welders who pass inspect continuously, not just at the end. Catching a defect between passes means grinding it out in seconds. Catching it at visual inspection means starting over.

Testing and Acceptance: Visual Inspection and the Guided Bend Test

Running a clean-looking bead uphill is the easy part. What happens after you lay the stinger down is where most candidates find out whether they actually passed. A 3G coupon is judged in two strict stages: a visual examination first, and only then a destructive guided bend test. There is no skipping ahead, no negotiating, and no re-guessing what the inspector saw.

Visual First, Destruction Second

Before any cutting wheel touches the plate, AWS D1.1 requires the entire test coupon to pass visual examination over its whole surface. That means the weld face, the root side, the start and stop points, and the heat-affected zones all get looked at closely. The vocabulary used for that inspection is defined in AWS’s standard welding terms and definitions, so an inspector’s report should always reference terminology you can look up rather than someone’s personal opinion (AWS A3.0 welding terminology standard).

This stage is where most welders are rejected, and it happens before a single specimen is bent. Cracks, visible lack of fusion, incomplete penetration at the root, undercut past the permitted limit, porosity clusters, or underfill are all grounds for failure right there. If visual fails, guided bend specimens and any mechanical testing are simply not performed. The coupon goes no further.

Cutting and Preparing the Bend Specimens

Once visual passes, the coupon is sectioned into specimens: two face bend specimens and two root bend specimens, so both sides of the weld get tested in tension. A face bend pulls the weld face into tension, exposing surface-breaking flaws. A root bend pulls the root into tension, which is why root defects that looked acceptable on paper tend to announce themselves in the jig.

Preparation is meticulous because a sloppy specimen can fail for reasons that have nothing to do with your welding:

• Reinforcement is ground flush with the base metal surface so the bend is uniform.
• The backing bar, if one was used, is removed and the back ground smooth.
• Corners and edges are radiused, typically to about 1/8 in (3 mm), so the specimen does not crack at a sharp edge during the bend.
• Grinding marks are kept parallel to the weld, and heat from grinding is avoided so the specimen is not inadvertently softened.

Each prepared specimen is then loaded into the guided bend jig and bent 180 degrees around the mandrel. The bend happens in one continuous motion, and the side that was stretched becomes the convex surface you will read afterward.

Reading the Convex Surface: The Acceptance Limits

The convex (outer, stretched) surface is the surface that tells the truth. Weld reinforcement, previously hiding small flaws, is stretched open here. Acceptance is judged against specific size limits rather than eyeballed:

Condition on convex surface	Acceptance limit
Any single discontinuity	No single discontinuity longer than 1/8 in (3 mm) in any direction
Small discontinuities over 1/32 in but not more than 1/8 in	Combined length must not total more than 3/8 in (10 mm)
Corner cracks	Disregarded up to 1/4 in (6 mm), unless they trace to a visible slag inclusion or other fusion-type defect, in which case the 1/8 in limit applies
Cracks elsewhere, lack of fusion, incomplete penetration	Rejectable regardless of size

Practical walkthroughs of the full coupon-to-bend process for SMAW, GMAW, and FCAW are published by training programs such as GoWelding’s 3G SMAW qualification guide, and the AWS Welding Digest has a useful checklist for passing a weld test that matches what inspectors look for in practice. Community-college qualification handouts, like Portland Community College’s qualification and certification overview, spell out the same visual-before-mechanical sequence.

What Passing 3G Actually Qualifies You To Do

A successful 3G groove coupon is a performance qualification, not a lifetime badge. It qualifies you to make groove welds in the vertical position on plate within the thickness range your coupon covered, along with the lower and equal positions the code allows from that test. It does not by itself qualify overhead groove work (4G), it does not qualify pipe, it does not certify you to a company procedure you have never welded to, and it says nothing about your ability to run the other processes if you tested in only one.

Equally important, a coupon pass is not the same as an AWS Certified Welder credential or a continuous record of qualification. Your employer must keep the test record, and the qualification stays valid only while continuity is maintained.

The exact position and thickness ranges you earn from a 3G pass, and why 4G does not simply absorb it, are covered in the next section.

What a 3G Qualification Covers (and What It Doesn’t)

Passing a 3G test feels like a big win, and it is. But plenty of welders are surprised to learn exactly how much ground that one test covers, and more importantly, how much it doesn’t. Your qualification isn’t a blanket license to weld anything in any position. It’s a defined range written on a record, and the boundaries matter when a supervisor assigns you work or an inspector asks for your paperwork.

The Range a Single 3G Groove Test Opens Up

Under AWS welding terminology and qualification conventions, positions are tracked individually, and the tables in AWS D1.1 (Table 6.10 in recent editions) spell out what each test buys you. The headline result looks like this:

Test you pass	Groove positions qualified	Fillet positions qualified
3G only	1G, 2G, 3G	1F, 2F, 3F
4G only	1G, 2G, 4G	1F, 2F, 4F
3G + 4G	1G, 2G, 3G, 4G (all-position)	1F, 2F, 3F, 4F

Read the first row carefully, because it’s better news than most candidates expect. A single vertical groove test qualifies you for flat, horizontal, and vertical groove welds, plus fillet welds in flat, horizontal, and vertical positions. That covers the overwhelming majority of structural work in a fabrication shop. The 3G SMAW qualification path is popular precisely because of that reach: one test, six practical positions.

The Two Positions 3G Never Covers

Only two positions sit outside a 3G qualification: overhead groove (4G) and overhead fillet (4F). If a job drawing or a shop procedure calls for overhead work, a 3G card alone won’t satisfy the requirement. This is where candidates get caught in interviews. A foreman asks, “Are you all-position?” and a welder who has only tested 3G answers yes when the honest answer is “all-position except overhead.”

Here’s the counterintuitive part that catches people off guard: a standalone 4G test does not absorb vertical. Overhead is its own distinct skill, and vertical is its own distinct skill. The code treats them as separate competencies because the gravity effects, puddle control, and body positioning are fundamentally different. You can be an excellent overhead welder and still fail a 3G test cold. The same works in reverse, which is why the same table shows a 4G qualifying 1G, 2G, 4G groove and 1F, 2F, 4F fillet while leaving 3G completely out.

How Thickness Ranges Work

Position is only one axis. AWS D1.1 also ties your qualification to a thickness range, and the range depends on the thickness of the coupon you actually welded. In broad terms, a test on thinner plate qualifies a range of production thicknesses, and a test on a thicker coupon can extend qualification to unlimited thickness, with the minimum qualified thickness generally tied to the coupon itself. The key idea: your qualified thickness is earned through testing, not assumed. Before you accept a work assignment, confirm that the production plate falls inside the range printed on your record. Welding outside your qualified range is a code violation even if the weld looks perfect.

Continuity and Renewal

Qualifications don’t last forever on paper alone. AWS D1.1 requires continuity of qualification, meaning the employer must maintain records proving the welder has been actively welding within the qualified processes and positions. If a welder goes six months without performing the qualified weld type, requalification is typically required. Employers track this with continuity records tied to specific process qualifications like vertical-up GMAW and job assignments. If you leave a shop and move to another, expect the new employer to either verify your previous records or, far more commonly, test you again on their own coupon to their own WPS.

WPQ Record vs. AWS Certified Welder Card

This distinction trips up even experienced welders. A welder qualification test produces a Welder Performance Qualification (WPQ) record: a document issued by a specific employer, specific code, and specific WPS, stating exactly which positions, processes, and thicknesses that employer has qualified you for. It belongs to the employer’s records, not to you as a portable credential.

An AWS Certified Welder card, by contrast, is an individual credential administered by the American Welding Society. It’s portable across employers, but it’s a certification of demonstrated skill rather than a code-mandated employer qualification. Passing a 3G test for your company earns you a WPQ entry; it does not automatically make you an AWS Certified Welder, and holding an AWS card does not automatically satisfy a fabricator’s D1.1 qualification requirements. Some employers want both; many want only the WPQ. Know which one the job posting is actually asking for before you walk in.

The practical takeaway is simple: read your qualification range the way an inspector does. Position, process, thickness, and continuity all have to line up with the work in front of you. When they do, one vertical plate test becomes one of the most valuable credentials in structural welding. When they don’t, the fix is another test, not an argument.

Safety, Fume Control and Ergonomics in the 3G Position

Vertical welding is hard on the body in a way flat work never is. The puddle sits at eye level, your arms stay raised for hours, and the fume plume does something unhelpful: it rises straight into your face. In flat positions, buoyant fumes drift up and away from the arc zone. In 3G, the arc is already at head height, so the plume travels directly through your breathing zone before it has anywhere to go. That single physical fact is why fume control deserves more attention on vertical plate than on almost any other position.

Why the Plume Matters More in 3G

Welding fume is a mix of metal oxides from the consumable, the base metal, coatings, and shielding gases. What you actually inhale depends on the process, the filler, the ventilation, and how close your helmet sits to the arc. Vertical work pushes welders closer to the puddle for visual control, and natural convection from the hot arc carries the plume upward into the mask. A respirator helps, but it is the last line of defense, not the first. Dilution and capture come first.

OSHA’s general ventilation rule is straightforward: if a space holds less than 10,000 cubic feet per welder, has a ceiling lower than 16 feet, or has obstructed cross ventilation, mechanical ventilation delivering at least 2,000 cubic feet per minute per welder is required, per 29 CFR 1926.353. In open shop bays with high ceilings, natural ventilation may suffice. Under a low mezzanine or inside a stair tower, it will not.

The Exposure Limits Behind the Rules

Three numbers explain why shops write the ventilation procedures they do:

• Total welding fume: OSHA’s permissible exposure limit is 5 mg/m³ as an 8-hour average for welding iron, mild steel, or aluminum.
• Hexavalent chromium: Welding stainless steel, chromate-coated material, or certain hardfacing alloys generates Cr(VI). OSHA’s PEL is 5 µg/m³ as an 8-hour time-weighted average under 29 CFR 1910.1026.
• Manganese: NIOSH recommends a 1 mg/m³ TWA and a 3 mg/m³ short-term limit. Manganese is present in mild-steel fume, so this applies to ordinary 3G plate work, not just exotic alloys. See NIOSH’s welding health topic for current guidance.

OSHA’s welding safety fact sheet summarizes engineering controls and PPE expectations, and university EHS guidance offers useful shop-level setup examples.

PPE, Fire Watch and Hot Work

The basics do not change in vertical position, but they matter more when spatter falls toward your arms and shoulders:

• An auto-darkening helmet with the correct shade, plus safety glasses underneath at all times.
• Leather jacket or sleeved leathers, gauntlet gloves, and a cap under the helmet. Vertical arcs throw spatter upward and outward.
• Fire watch during and for at least 30 minutes after hot work on combustible surfaces, per OSHA’s fire watch interpretation.
• Boots with full coverage and no open cuffs where sparks can drop in.

Ergonomics: The Fatigue Nobody Trains For

Sustained shoulder-height work is genuinely demanding. Holding a stinger or gun above chest level for a full pass narrows your range of motion, tightens the neck, and quietly degrades the fine hand control a clean vertical weave depends on. Late-shift root passes wander because the welder is tired, not because the technique failed.

Countermeasures are simple: position your body so the work stays between your shoulders rather than above your head, use both hands to steady the stinger on long passes, take short breaks between passes to drop your arms, and set the coupon height to suit you during practice so test day is not the first time you feel the strain. Fatigue shows up as a wandering arc, a cold puddle, and undercut you stop noticing before the inspector does.

Treat ventilation, PPE and body mechanics as part of your technique rather than separate from it. A welder who controls the environment controls the puddle, and that control is exactly what a 3G test measures.

How to Prepare, Practice and Pass the 3G Test First Time

Most welders who fail a 3G qualification test fail because they practiced the wrong way. They ran comfortable beads on comfortable plate, ground everything smooth, and discovered on test day that there was no grinder, no second attempt, and no patience for a root pass they had never drilled to automatic. Passing is far more about preparation than talent, and nearly all of that preparation happens before you strike an arc in front of an inspector.

Do Your Homework Before Test Day

The most useful thing you can do is arrive knowing the rules. AWS Welding Digest’s guidance on passing a weld test recommends confirming five things before your test date:

• The governing code — AWS D1.1 for structural steel, D1.2 for aluminum, ASME Section IX for pressure work, or an employer-specific specification.
• The visual acceptance criteria — reinforcement limits, undercut depth, weld face width, and whether face and root are judged visually first.
• Inspection hold points — where the process stops for inspection, usually after visual exam and before any specimen is cut.
• The test method — guided bend testing or radiographic examination, which demand different finish habits. A bend test tolerates no face defect you leave behind; a radiograph punishes slag or porosity trapped inside the weld.
• Allowed cleaning methods — whether you may grinder the finished coupon, and how much reinforcement you leave before it is machined off.

Request the WPS or procedure qualification record in advance and actually read it. Amperage range, electrode type, heat input limits, preheat and interpass temperatures, and fit-up dimensions should all be on paper. The terminology follows AWS A3.0, Standard Welding Terms and Definitions, so knowing the vocabulary keeps you from misreading a requirement under pressure.

Build a Repeatable Pre-Weld Checklist

Welders who pass consistently run the same routine every time, in practice and on test day:

1. Confirm machine settings against the WPS and check that the amperage meter reads what the dial claims.
2. Verify gas flow rate and check the liner, contact tip and ground clamp for wear or poor connection.
3. Measure root opening, land and bevel angle on the actual coupon, not the practice plate.
4. Clean the joint faces of oil, mill scale and moisture right before tacking.
5. Confirm preheat temperature if required, and have a way to measure interpass temperature.
6. Decide your sequence: root, hot pass or first fill, fill passes, cap. Write it down if it helps.

Drill the Root Pass Until It Is Automatic

Root pass acceptance decides most 3G tests. Incomplete penetration and lack of root fusion are the classic killers, and both come from an inconsistent arc length, an electrode angle that drifts, or travel speed that changes when nerves kick in. Practice the root until you can run it on the specific gap and amperage you will be given without thinking. If you can get hands on the process first, step-by-step 3G SMAW preparation guides are useful for knowing what a qualification coupon looks like before you build one yourself.

Practice under the no-grind assumption. Treat every pass as if no grinder will be available, because the one day you need it is the day it goes missing. Learn to dress a pass with the electrode or a light file touch-up, and a grinder on test day becomes a bonus rather than a crutch. When stacking fill passes, stagger starts and stops so that the inevitable imperfections from restarting never pile up where a bend specimen will find them.

Handle Test-Day Nerves

Adrenaline tightens your arc hand and shortens your thinking. Counter it by arriving early, running your checklist out loud, and giving yourself a deliberate pause before the root. Breathe out as you start the pass. Nerves mostly disappear once the first 50 mm of root is behind you, so protect that stretch and let the rhythm take over.

Top Mistakes Candidates Make (and How to Avoid Them)

Rejection Cause	Why It Happens in the 3G Position	The Fix
Porosity	Contamination: oil, rust, moisture, or damp low-hydrogen electrodes	Clean the joint, store E7018 rods in a rod oven, and check gas shielding
Incomplete fusion	Travel speed too fast, arc riding ahead of the puddle	Slow down, hold the arc on the toes, let the puddle wash into the sidewall
Incomplete penetration	Wrong root gap or too little amperage	Measure fit-up, stay inside the WPS range, keep arc length tight
Undercut	Weave held too long at the edges	Pause in the middle, move quickly across, keep weave width in check
Slag inclusion	Slag trapped between passes or in the corners of the joint	Wire-brush and chip every pass, verify the toe is clean before reloading
Cracking	Improper preheat or damp low-hydrogen consumables	Follow preheat and interpass requirements exactly, use dry electrodes

Read your own weld before the inspector does. Check reinforcement height, undercut depth, width consistency, and the start and stop areas with the same eye an inspector brings. If something looks wrong while it is still hot, you can often fix it. If it waits until visual inspection, you are finished.

Conclusion: What to Take Away

Passing the 3G test first time comes down to a short list of habits:

• Confirm the governing code, acceptance criteria, inspection hold points, test method and cleaning rules before the test date.
• Read the WPS and follow the same checklist every time.
• Make the root pass automatic through repetition on the actual gap and settings.
• Practice as though no grinder exists, and stagger starts and stops so defects never cluster.
• Self-inspect and clean between passes, and hold your interpass temperature.
• Know the six rejection causes well enough to spot them in your own work while the weld is still hot.

Do those things and the foreman’s question — “Can you run vertical?” — stops being an interrogation and starts being a formality. The welder who prepares this way doesn’t just pass the 3G; they walk onto the job already trusted with the joints that hold buildings and bridges together.

Frequently Asked Questions

What does 3G mean in welding?

3G means a groove weld made in the vertical position on plate. The plate stands upright, the weld axis runs vertically, and under AWS D1.1 the welder progresses from the bottom upward. The number 3 designates the vertical position and the G designates a groove joint rather than a fillet joint.

What positions does a 3G test qualify you for?

Passing a 3G groove test under AWS D1.1 qualifies you for flat (1G), horizontal (2G) and vertical (3G) groove welds, plus fillet welds in the 1F, 2F and 3F positions. It does not qualify you for overhead groove (4G) or overhead fillet (4F) welding.

Is 3G welding uphill or downhill?

The standard 3G qualification test is vertical uphill only. AWS D1.1 sets upward progression as the default for vertical passes, and direction of travel is an essential variable — a 3G uphill ticket does not automatically cover downhill production welding.

How is a 3G test coupon evaluated?

The coupon is first visually examined over its entire surface; if it passes, two face bend and two root bend specimens are cut and bent 180 degrees in a guided bend jig. The convex surface may show no single discontinuity longer than 1/8 inch, and the total of discontinuities over 1/32 inch must not exceed 3/8 inch.

What is the difference between 3G and 4G?

3G is a vertical groove weld test that qualifies flat, horizontal and vertical positions, while 4G is an overhead test that qualifies flat, horizontal and overhead positions. Neither absorbs the other — only the combined 3G/4G test gives full all-position plate coverage.

Why is vertical-up preferred over vertical-down on structural plate?

Vertical uphill uses slower travel and higher heat input to produce deeper penetration, complete fusion and a well tied-in root. Downhill is faster but carries a higher risk of cold lap, incomplete fusion and slag entrapment at the toes, so D1.1 treats downhill CJP groove welding as requiring separate qualification.

What are the most common reasons for failing a 3G test?

The most frequent failures are incomplete fusion, porosity from contaminated base metal or bad shielding, incomplete penetration in the root, undercut exceeding the 1/32 inch limit, slag inclusions from poor interpass cleaning, and cracks caused by improper preheat or damp low-hydrogen electrodes.

Do I need 3G certification to work as a structural welder?

Most structural fabrication and field erection jobs built to AISC-designed specifications require at minimum a 3G plate qualification, since it covers the flat, horizontal and vertical groove welds that dominate the work. If the job also involves overhead groove welding, you will need to add the 4G test.