Welding Troubleshooting

The rod freezes to the metal when you strike, or the arc keeps going out.

1. Amps too low

   How to tell

   The arc is hard to start, the rod sticks again and again, and the arc sputters as if it’s about to go out.

   Fix

   Turn the amps up in small steps. Start in the middle of the range for your rod and size.

   Stick Welding Amperage Chart by Rod Size

   Source: Introduction to Welding 8.4; Randy’s rod sticking guide

2. Striking too hard

   How to tell

   It sticks the moment you strike, then runs fine once the arc is going.

   Fix

   Strike like a match: a quick, light scratch, then lift to arc length. Scratching is easier than tapping, and pressing harder only makes it stick.

   Source: Introduction to Welding 8.4; Randy’s rod sticking guide

3. Arc too short

   How to tell

   It sticks partway along the weld, and the bead piles up cold before it does.

   Fix

   Hold a gap of about one rod diameter between the rod tip and the pool.

   Source: Introduction to Welding 8.4

4. Rust, paint or a dirty ground

   How to tell

   It is hard to start on rusty or painted steel but fine on clean metal.

   Fix

   Grind to bright metal where you weld and where the ground clamp goes. Rust adds resistance, so less current reaches the arc.

   Source: Randy’s rod sticking guide

5. Damp or damaged flux

   How to tell

   The coating is cracked, chipped or crumbling, or the rods sat out in damp air.

   Fix

   Use rods with a sound coating, and store and re-dry them as the oven chart says.

   Welding Rod Oven Temperature Chart

   Source: Randy’s rod sticking guide; Randy’s guide to heating rods

6. The machine struggles to start an arc

   How to tell

   A machine with low open-circuit voltage loses the arc and sticks whatever you do.

   Fix

   Turn up hot start or arc force (dig) if the machine has it; it helps keep the rod from sticking on a short arc.

   Source: Introduction to Welding 8.4; Randy’s rod sticking guide

Round pinholes or bubbles on the surface or inside the weld: gas trapped as the metal froze.

1. Arc too long, or porosity at the start

   How to tell

   Pores cluster where each rod starts, or along a stretch held with a long, noisy arc; common with E7018.

   Fix

   Hold a tight arc, about one rod diameter. Strike a little ahead of the joint, then move back over the start and weld on (backstep), so the first metal is remelted.

   Source: Introduction to Welding 8.4

2. Damp rods

   How to tell

   Pores keep showing on clean steel, most often with low-hydrogen rods like 7018 that were left out of the oven.

   Fix

   Use rods straight from the oven, or re-dry them. Standard 7018 should go back in the oven within about 4 hours.

   Welding Rod Oven Temperature Chart

   Source: Randy’s guide to heating rods

3. Dirty metal

   How to tell

   Pores where rust, oil, paint or grease was left on the steel.

   Fix

   Grind or degrease to bright metal. Stick copes with dirt better than MIG, but not with heavy contamination.

   Source: Lincoln Electric

4. Damp weather

   How to tell

   You are welding outside in rain, fog or mist.

   Fix

   Shelter the work and keep the rods dry. Preheating the part drives off moisture.

   Source: Randy’s welding-in-the-rain guide

Balls of metal stuck around the weld, on the plate and in the nozzle.

1. Amps too high

   How to tell

   A wide, flat bead, undercut at the edges, and a long teardrop-shaped pool instead of an oval.

   Fix

   Turn the amps down.

   Stick Welding Amperage Chart by Rod Size

   Source: Introduction to Welding 8.4

2. Arc too long

   How to tell

   The arc is loud and violent, and the pool runs hot and fluid.

   Fix

   Close the gap to about one rod diameter.

   Source: Introduction to Welding 8.4

3. Arc blow

   How to tell

   The arc pulls to one side and throws spatter, worst near the ends of the joint.

   Fix

   Move the ground clamp or switch to AC (see “Arc wanders or blows to one side”).

   Source: Introduction to Welding 8.4

4. Damp rods

   How to tell

   The rods were left out of the oven or in damp air.

   Fix

   Use dry rods: dry low-hydrogen rods give a steadier arc with less spatter.

   Welding Rod Oven Temperature Chart

   Source: Randy’s guide to heating rods

A groove melted into the plate along the edge (toe) of the weld and left unfilled.

1. Amps too high

   How to tell

   A wide, flat bead with grooves at the edges and plenty of spatter.

   Fix

   Turn the amps down.

   Stick Welding Amperage Chart by Rod Size

   Source: Introduction to Welding 8.4

2. Arc too long

   How to tell

   Undercut comes with spatter and a violent arc.

   Fix

   Hold a gap of about one rod diameter.

   Source: Introduction to Welding 8.4

3. Travel too fast

   How to tell

   A narrow bead with grooves along both edges.

   Fix

   Slow down so the pool fills the edges before you move on.

   Source: Introduction to Welding 8.4

Weld metal rolls over the edges or sits on the plate without melting into it.

1. Travel too slow

   How to tell

   The bead piles up and rolls over the edges.

   Fix

   Speed up.

   Source: Introduction to Welding 8.4

2. Arc too short

   How to tell

   A cold-looking bead that sits on top, and the rod keeps trying to stick.

   Fix

   Lift to about one rod diameter.

   Source: Introduction to Welding 8.4

3. Amps too low

   How to tell

   A narrow bead with a high crown and little penetration.

   Fix

   Turn the amps up.

   Stick Welding Amperage Chart by Rod Size

   Source: Introduction to Welding 8.4

A high, rounded bead that sits on the surface with little penetration.

1. Amps too low

   How to tell

   A narrow, high-crowned bead, and the rod sticks or sputters too.

   Fix

   Turn the amps up.

   Stick Welding Amperage Chart by Rod Size

   Source: Introduction to Welding 8.4

2. Travel too fast

   How to tell

   A narrow pool and a thin, stringy bead.

   Fix

   Slow down.

   Source: Introduction to Welding 8.4

The arc melts holes through the plate, or the weld sags out the back.

1. Amps too high

   How to tell

   The arc digs at the edges and melts through.

   Fix

   Turn the amps down.

   Stick Welding Amperage Chart by Rod Size

   Source: Introduction to Welding 8.4

2. Rod too big for the metal

   How to tell

   A thick rod on thin sheet needs more amps than the sheet can take.

   Fix

   Use a smaller rod: 3/32 in on 1/8–⁠3/16 in plate (ESAB). ESAB doesn’t recommend stick on very thin sheet; if you must, use the smallest rod (1/16–⁠5/64 in) at the bottom of its range.

   Stick Welding Amperage by Metal Thickness

   Source: ESAB

3. A digging rod on thin metal

   How to tell

   You are running E6010 or E6011, which dig deep.

   Fix

   E6013 has a soft, shallow arc made for sheet metal.

   Welding Rod Chart and Number Decoder

   Source: Introduction to Welding 8.3

Pockets or lines of slag left inside the weld or between passes.

1. Slag not cleaned between passes

   How to tell

   Slag lines between the passes of a multi-pass weld.

   Fix

   Chip and wire-brush every pass before you run the next.

   Source: Hobart Brothers; Introduction to Welding 19.2

2. Slag running ahead of the arc

   How to tell

   Slag rolls in front of the pool and gets welded over.

   Fix

   Drag the rod (lean it back toward the finished weld) and keep the arc ahead of the slag.

   Source: Hobart Brothers

3. Too cold

   How to tell

   The slag freezes before it can float out of the pool.

   Fix

   Turn the amps up a little.

   Stick Welding Amperage Chart by Rod Size

   Source: Hobart Brothers

4. No room for the next pass

   How to tell

   Inclusions at the sides of a deep or narrow groove.

   Fix

   Place each bead so the next one has room, and open the groove if needed.

   Source: Hobart Brothers

Cracks along the bead, at its edges, or in the dip where the weld stopped.

1. Hydrogen from damp rods

   How to tell

   Cracks at the edges or under the bead, mostly with low-hydrogen rods that picked up moisture.

   Fix

   Keep low-hydrogen rods dry in an oven, and re-dry any that sat out.

   Welding Rod Oven Temperature Chart

   Source: Randy’s guide to heating rods

2. Crater left unfilled

   How to tell

   A small crack in the dip where the weld stopped.

   Fix

   Pause to fill the crater before you break the arc.

   Source: Introduction to Welding 19.2

3. The weld cools too fast

   How to tell

   Cold, damp conditions or thick plate.

   Fix

   Preheat the part before welding.

   Source: Randy’s welding-in-the-rain guide

The arc bends away from where you point the rod, often near the ends of a joint.

1. Magnetic arc blow on DC

   How to tell

   The arc bends away from where you point it, near the ends of a joint or a corner.

   Fix

   Move the ground clamp, use more than one clamp, or switch to AC.

   Welding Polarity Chart: DCEP, DCEN or AC

   Source: Introduction to Welding 8.4

2. Long arc or high amps

   How to tell

   A long, wandering arc at high current.

   Fix

   Use the lowest amps that still weld well, hold a tight arc, and adjust arc force (dig).

   Source: Introduction to Welding 8.4

Round pinholes or bubbles on the surface or inside the weld: gas trapped as the metal froze.

1. Dirty metal

   How to tell

   Pores where rust, oil, paint or grease was left.

   Fix

   Grind or degrease first. Never use a chlorinated degreaser near the arc: its fumes can turn into toxic gas.

   Source: Lincoln Electric

2. Not enough gas reaching the weld

   How to tell

   Pores all along the weld.

   Fix

   Set about 30–⁠40 CFH on a flowmeter (a pressure regulator alone doesn’t set flow) and check hoses, fittings and the gun for leaks.

   Source: Lincoln Electric; Miller Electric

3. Drafts or wind

   How to tell

   Pores outdoors, or near a fan or an open door.

   Fix

   Put up a screen. The AWS D1.1 structural code does not allow gas-shielded welding in wind over 5 mph (8 km/h) unless the weld is sheltered.

   Source: AWS D1.1; Lincoln Electric

4. Clogged nozzle or too much flow

   How to tell

   Spatter built up in the nozzle or diffuser, or the flow turned right up.

   Fix

   Clean the nozzle and diffuser, and keep the flow in range: turbulent gas pulls air in.

   Source: Lincoln Electric; Introduction to Welding 9.2

5. Too much stickout or gun angle

   How to tell

   More than 1/2 in of wire past the nozzle, or the gun tipped steeply.

   Fix

   Keep stickout to 1/2 in or less and the gun angle small.

   Source: Miller Electric

6. Pulling the gun

   How to tell

   You drag (pull) the gun instead of pushing it.

   Fix

   Push at 5–⁠10° so the gas lies ahead of the arc and settles into the joint.

   Source: Lincoln Electric

7. Wet or bad gas cylinder

   How to tell

   Everything else checks out.

   Fix

   Swap the cylinder and tell your gas supplier.

   Source: Miller Electric

Balls of metal stuck around the weld, on the plate and in the nozzle.

1. Voltage too low

   How to tell

   A loud, raspy arc, and the wire stubs into the plate.

   Fix

   Raise the voltage a step at a time until the arc settles into a steady buzz.

   Source: Lincoln Electric

2. Voltage or travel speed too high

   How to tell

   A steady hiss, a wide bead and undercut.

   Fix

   Lower the voltage or slow down.

   Source: Miller Electric; Lincoln Electric

3. Too much stickout

   How to tell

   More than 1/2 in of wire showing past the nozzle.

   Fix

   Shorten it.

   Source: Miller Electric

4. Straight CO2 or poor gas coverage

   How to tell

   You run 100% CO2, or the flow is low.

   Fix

   Check the flow. A 75% argon, 25% CO2 mix (C25) spatters less than straight CO2.

   Source: Introduction to Welding 10.4; Miller Electric

5. Dirty metal or rusty wire

   How to tell

   Rust, mill scale or oil on the plate, or rust on the wire.

   Fix

   Clean the metal and replace rusty wire.

   Source: Miller Electric

6. Worn or wrong contact tip

   How to tell

   The tip hole is worn oval, or too big for the wire.

   Fix

   Fit a new tip of the right size for your wire.

   Source: Miller Electric; Lincoln Electric

A groove melted into the plate along the edge (toe) of the weld and left unfilled.

1. Voltage too high

   How to tell

   A steady hissing arc and grooves at the edges.

   Fix

   Turn the voltage down.

   Source: Lincoln Electric

2. Travel too fast

   How to tell

   A narrow bead with unfilled edges.

   Fix

   Slow down so the weld fills the edges.

   Source: Introduction to Welding 9.4; Hobart Brothers

3. Gun angle

   How to tell

   Undercut on one side only, such as the top edge of a horizontal fillet.

   Fix

   Aim the gun a little more toward that side, and pause at the edges if you weave.

   Source: Hobart Brothers

Weld metal rolls over the edges or sits on the plate without melting into it.

1. Gun angle or arc position

   How to tell

   The weld sits on the plate with an edge that never melted in.

   Fix

   Hold a 0–⁠15° gun angle and keep the arc on the leading edge of the pool.

   Source: Miller Electric

2. Not enough heat

   How to tell

   The bead looks fine but sits on top, often on thick plate with a small machine.

   Fix

   Raise the voltage or wire speed. Short-circuit welds can look good and still not fuse, so check with a bend test.

   Source: Miller Electric; Lincoln Electric

3. Travel too slow

   How to tell

   The pool rolls ahead of the arc and laps over the edges.

   Fix

   Speed up.

   Source: Miller Electric

4. Short-circuit MIG on thick plate

   How to tell

   Thick steel welded in short-circuit transfer.

   Fix

   Use flux core, or spray transfer, for heavy plate.

   Source: Lincoln Electric; Introduction to Welding 10.4

A high, rounded bead that sits on the surface with little penetration.

1. Settings too cold

   How to tell

   A high, rope-like bead with poor fusion at the edges.

   Fix

   Check that the wire speed (amps) suits the thickness, then raise the voltage.

   Source: Lincoln Electric; Miller Electric

2. Pulling the gun

   How to tell

   You weld with a pull (drag) angle.

   Fix

   Push at 5–⁠10° for a flatter bead.

   Source: Lincoln Electric

3. Work cable too small or worn

   How to tell

   The work cable or ground clamp gets hot.

   Fix

   Fit a cable sized for your amps and its length, and clamp to clean metal.

   Source: Lincoln Electric

The arc melts holes through the plate, or the weld sags out the back.

1. Too much heat

   How to tell

   Holes in metal thinner than about 1/8 in.

   Fix

   Lower the voltage or the wire speed.

   Source: Miller Electric

2. Travel too slow

   How to tell

   Heat builds up in one spot.

   Fix

   Move faster. This matters most on thin aluminum.

   Source: Miller Electric

Wire tangles at the drive rolls, feeds unevenly, or welds itself to the contact tip.

1. Drive roll tension

   How to tell

   The wire slips at the rolls (too loose), or comes out flattened and tangles (too tight).

   Fix

   With the welding output off, feed the wire and pinch it where it leaves the gun. If your fingers can stop it, add tension; stop adding once they can’t.

   Source: Lincoln Electric

2. Worn or wrong drive rolls

   How to tell

   Worn grooves, or a groove that doesn’t match the wire.

   Fix

   Match the roll to the wire size: V groove for steel, U groove for aluminum.

   Source: Introduction to Welding 10.2; Lincoln Electric

3. Dirty, kinked or wrong-size liner

   How to tell

   The wire drags when you pull it by hand, or the gun cable is coiled tight.

   Fix

   Blow the liner out from the tip end with low-pressure air or replace it, and keep the cable straight.

   Source: Lincoln Electric; Introduction to Welding 9.2

4. Worn or wrong contact tip

   How to tell

   Burnback (the wire welds itself to the tip) or an unsteady arc.

   Fix

   Replace the tip with one sized for your wire.

   Source: Lincoln Electric

5. Spool coasting

   How to tell

   Loose loops on the spool after you let go of the trigger.

   Fix

   Tighten the spool brake until the spool stops when the wire stops.

   Source: Lincoln Electric

6. Aluminum wire in a standard gun

   How to tell

   Soft aluminum wire jams in a long gun cable.

   Fix

   Use a plastic liner and a spool gun or push-pull gun.

   Source: Introduction to Welding 10.2

Round pinholes or bubbles on the surface or inside the weld: gas trapped as the metal froze.

1. Too much stickout

   How to tell

   The contact tip held farther from the work than the wire maker lists, or the distance keeps changing.

   Fix

   Hold the maker’s distance and keep it steady: about 1/2–⁠5/8 in from contact tip to work for small gasless wires like Lincoln NR-211-MP.

   MIG Welding Settings Chart

   Source: Hobart Brothers; Lincoln NR-211-MP data sheet; Introduction to Welding 9.4

2. Voltage too high

   How to tell

   Pores together with worm tracks on the bead.

   Fix

   Lower the voltage half a volt at a time.

   Source: Hobart Brothers

3. Dirty metal

   How to tell

   Rust, oil, paint, coatings or moisture left on the plate.

   Fix

   Clean the plate before welding.

   Source: Hobart Brothers

4. Impurities in the steel

   How to tell

   Steel high in sulfur or phosphorus.

   Fix

   Use a different grade of steel where the job allows.

   Source: Hobart Brothers

Small worm-shaped marks on the surface of a flux core bead.

1. Voltage too high for the wire speed

   How to tell

   Worm-shaped marks on the bead, sometimes with pores.

   Fix

   Start from the wire maker’s settings, then lower the voltage half a volt at a time until the marks stop.

   Source: Hobart Brothers

Pockets or lines of slag left inside the weld or between passes.

1. Pushing instead of dragging

   How to tell

   You push the gun, and slag runs ahead of the pool.

   Fix

   Drag the gun: 15–⁠45° in the flat, horizontal and overhead positions, 5–⁠15° vertical up.

   Source: Hobart Brothers

2. Too cold

   How to tell

   Slag lines on low settings.

   Fix

   Raise the voltage until the inclusions stop.

   Source: Hobart Brothers

3. Poor cleaning between passes

   How to tell

   Slag lines between the passes.

   Fix

   Clean every pass fully before the next.

   Source: Hobart Brothers

4. Bead placement

   How to tell

   Inclusions in the corners of deep grooves.

   Fix

   Leave room for the next pass, and widen the groove if needed.

   Source: Hobart Brothers

Balls of metal stuck around the weld, on the plate and in the nozzle.

1. Wrong polarity

   How to tell

   Heavy spatter and a harsh arc. Most gasless wire (E71T-⁠11, E71T-⁠8) runs electrode negative; check the spool.

   Fix

   Set the polarity the spool gives: for E71T-⁠11 the gun lead goes on negative (DCEN) and the ground on positive. Drag the gun.

   Welding Polarity Chart: DCEP, DCEN or AC

   Source: Miller Electric

2. Voltage too low

   How to tell

   Spatter with a rough, stubbing arc.

   Fix

   Raise the voltage.

   Source: Miller Electric

3. Long stickout or worn tip

   How to tell

   Lots of wire showing, or a tip worn oval.

   Fix

   Shorten the stickout and replace the tip.

   Source: Miller Electric

A groove melted into the plate along the edge (toe) of the weld and left unfilled.

1. Current or voltage too high

   How to tell

   Grooves at the edges of a wide, hot bead.

   Fix

   Turn the wire speed and voltage down.

   Source: Hobart Brothers

2. Travel too fast

   How to tell

   A narrow bead with unfilled edges.

   Fix

   Slow down so the weld fills the edges.

   Source: Introduction to Welding 9.4; Hobart Brothers

3. Gun angle or weave

   How to tell

   Undercut on one side only.

   Fix

   Adjust the angle, and pause at each side when you weave.

   Source: Hobart Brothers

Weld metal rolls over the edges or sits on the plate without melting into it.

1. Travel too slow

   How to tell

   A tall, convex bead that laps over the edges.

   Fix

   Speed up so the pool doesn’t get ahead of the wire.

   Source: Introduction to Welding 9.4; Hobart Brothers

2. Travel too fast

   How to tell

   A small bead that didn’t fuse at the edges.

   Fix

   Slow down.

   Source: Introduction to Welding 9.4

3. Too cold

   How to tell

   Shallow fusion on thick plate.

   Fix

   Raise the voltage and wire speed.

   Source: Hobart Brothers

4. Angle or joint access

   How to tell

   Unfused sidewalls in a groove weld.

   Fix

   Aim into the joint with a 15–⁠45° drag, and hold the arc briefly on each sidewall when you weave.

   Source: Hobart Brothers

5. Dirty metal

   How to tell

   Rust, scale or paint in the joint.

   Fix

   Clean the joint before welding.

   Source: Hobart Brothers

The arc melts holes through the plate, or the weld sags out the back.

1. Too much heat

   How to tell

   The weld melts through and hangs under the joint.

   Fix

   Pick a lower voltage, lower the wire speed, and travel faster.

   Source: Hobart Brothers

Wire tangles at the drive rolls, feeds unevenly, or welds itself to the contact tip.

1. Wrong drive rolls

   How to tell

   Crushed or flattened wire.

   Fix

   Flux core wire is soft and hollow: use knurled V-groove rolls.

   Source: Hobart Brothers; Introduction to Welding 9.2

2. Drive roll tension too high

   How to tell

   Flattened wire that birdnests at the rolls.

   Fix

   Release the tension, then tighten it while feeding the wire into your gloved palm, stopping half a turn past where it slips.

   Source: Hobart Brothers

3. Blocked or wrong liner

   How to tell

   The wire drags in the gun cable.

   Fix

   Replace a blocked liner, trim it to the maker’s length, and use the size for your wire.

   Source: Hobart Brothers

4. Burnback

   How to tell

   The wire welds itself to the contact tip.

   Fix

   Raise the wire speed, don’t hold the tip closer than the maker’s distance (about 1/2–⁠5/8 in for small gasless wires), and replace the tip.

   Source: Hobart Brothers; Lincoln NR-211-MP data sheet

Round pinholes or bubbles on the surface or inside the weld: gas trapped as the metal froze.

1. Wrong gas

   How to tell

   The cylinder holds a MIG mix (argon with CO2).

   Fix

   Use 100% argon, or an argon-helium mix for thick aluminum.

   Source: Miller Electric

2. Gas flow too low or too high

   How to tell

   Pores or a sooty weld, with the flow far from 15–⁠20 CFH.

   Fix

   Set 15–⁠20 CFH. More is not better: too much flow makes turbulence that pulls air in.

   Source: Miller Electric; Introduction to Welding 11.2

3. A leak

   How to tell

   The flow is right, but the weld is still contaminated.

   Fix

   Brush soapy water on every fitting and hose. Bubbles mean a leak; replace that part.

   Source: Miller Electric

4. Drafts

   How to tell

   A fan, open door or wind nearby.

   Fix

   Block the draft.

   Source: Introduction to Welding 20.2

5. Dirty base or filler metal

   How to tell

   Mill scale, oil, oxide or dirt left on the metal or the filler rod.

   Fix

   Grind off mill scale, then wipe the metal and filler clean with acetone.

   Source: Miller Electric; Introduction to Welding 11.4

6. Loose torch parts

   How to tell

   A loose collet body or cup.

   Fix

   Tighten the torch parts.

   Source: Introduction to Welding 11.2

The tip turns black or lumpy, or melts into a big ball, and the arc wanders.

1. Touching the pool or the filler

   How to tell

   The tip turns black or lumpy after a dip, and the arc starts to wander.

   Fix

   Stop and regrind or replace the tungsten straight away. Welding on with it only makes the weld worse.

   Source: Introduction to Welding 11.4

2. Too much electrode positive on AC

   How to tell

   The tip melts into a big ball when you weld aluminum.

   Fix

   Give it less electrode-positive time in the AC balance (on Miller-style controls, turn the balance up).

   Source: Miller Electric

Black specks, a brown film or a dull, contaminated bead on aluminum.

1. DC instead of AC

   How to tell

   A bead full of melted oxide.

   Fix

   Weld aluminum on AC: the positive half cleans the oxide, the negative half melts the metal.

   Welding Polarity Chart: DCEP, DCEN or AC

   Source: Miller Electric

2. Not enough cleaning

   How to tell

   A brown film, or flakes like black pepper, in the pool.

   Fix

   Give it more electrode-positive (cleaning) time in the AC balance (on Miller-style controls, turn the balance down).

   Source: Miller Electric

3. Filler added too soon

   How to tell

   Specks appear as soon as you dip the rod.

   Fix

   Wait until the pool looks like a shiny dot before you add filler.

   Source: Miller Electric

4. Oxide or dirt left on

   How to tell

   The metal wasn’t cleaned just before welding.

   Fix

   Clean it right before welding with a stainless brush kept only for aluminum.

   Source: Introduction to Welding 21.2; Miller Electric

Weld metal rolls over the edges or sits on the plate without melting into it.

1. Arc too long

   How to tell

   The arc wanders between the sides of the joint.

   Fix

   Shorten the arc so the heat goes where you aim it.

   Source: Miller Electric

2. Poor fit-up

   How to tell

   Gaps or uneven edges in the joint.

   Fix

   Fit the parts tight and even before welding.

   Source: Miller Electric

3. Rushing or under-filling

   How to tell

   A thin weld that didn’t melt into the root.

   Fix

   Keep a steady travel speed and add enough filler.

   Source: Miller Electric

Cracks along the bead, at its edges, or in the dip where the weld stopped.

1. Stopping abruptly

   How to tell

   A crack in the crater at the end of the weld.

   Fix

   Ease the current down while you keep adding filler, or use the machine’s crater fill.

   Source: Miller Electric; Introduction to Welding 11.4

A gray or dark weld, or a rough, crusty (sugared) back side on stainless steel.

1. Too much heat

   How to tell

   A gray or dark weld. It can’t be undone, so it has to be prevented.

   Fix

   Lower the amps, travel a little faster or shorten the arc, and use pulse if your machine has it.

   Source: Miller Electric

2. No back purge

   How to tell

   A rough, crusty back side (sugaring).

   Fix

   Back purge the joint with argon, and lower the amps.

   Source: Miller Electric

The arc melts holes through the plate, or the weld sags out the back.

1. Too many amps

   How to tell

   A wide, shapeless bead on aluminum, or holes in thin metal.

   Fix

   Lower the amps and travel faster.

   Source: Miller Electric

2. Heat building up

   How to tell

   The part gets hotter as you go and the pool grows.

   Fix

   Tighten the arc and travel faster.

   Source: Introduction to Welding 11.4