Weld Defect Troubleshooter

Select what you see wrong with your weld and the electrode you are using. This tool returns the most likely causes ranked for your specific consumable, with fixes you can apply on the spot.

Diagnose Your Weld Defect

Select the defect you see, then pick your electrode. You will get causes ranked by likelihood for that specific consumable, with fixes you can try immediately.

Reference data only. Verify all settings against manufacturer documentation and the applicable welding code before use. Amperage ranges are starting points that vary by position, fit-up, and material. Welding involves serious injury risks including burns, electric shock, fume exposure, and fire. This site does not replace proper training, certification, or employer safety procedures. See full terms of use.

Weld Defect Reference

The reference below covers 8 common weld defects with descriptions, visual identification tips, and the most frequent causes by electrode type. Use this as a quick reference when you do not have the interactive tool available, or scroll through to learn the patterns.

Porosity

What it looks like: Bead looks spongy, has pin holes, or shows scattered small craters.

Small holes or gas pockets trapped in or on the surface of the weld bead.

Causes by electrode type (10 types covered)

Low-hydrogen (code quality)

Electrodes: E7016, E7018, E7018-1

  1. Moisture absorbed into electrode coating
  2. Arc length too long
  3. Contaminated base metal
  4. Travel speed too fast
  5. Wind disrupting shielding

Cellulosic (deep penetration)

Electrodes: E6010, E6011

  1. Travel speed too fast
  2. Arc length too long
  3. Contaminated base metal
  4. Amperage too low Settings

Rutile / Titania (smooth, easy arc)

Electrodes: E6012, E6013, E7014, E7024

  1. Contaminated base metal
  2. Arc length too long
  3. Travel speed too fast
  4. Amperage too low Settings

Solid MIG wire (gas shielded)

Electrodes: ER70S-6, ER70S-3, ER80S-D2

  1. Insufficient shielding gas flow
  2. Wind or drafts blowing away shielding gas
  3. Contaminated base metal
  4. Wrong gas or contaminated gas
  5. Nozzle too far from work or clogged with spatter
  6. Gas flow too high (turbulence)

Self-shielded flux-core wire

Electrodes: E71T-11, E71T-GS, E71T-8

  1. Voltage too high or too low Settings
  2. Wrong polarity Settings
  3. Stick-out too long
  4. Travel speed too fast
  5. Contaminated base metal

Gas-shielded flux-core wire

Electrodes: E71T-1, E81T1-Ni1

  1. Insufficient shielding gas flow
  2. Wind or drafts
  3. Contaminated base metal

Aluminum MIG/TIG wire

Electrodes: ER4043, ER5356, ER4047

  1. Oxide layer not removed
  2. Insufficient shielding gas
  3. Moisture or contamination on filler or base metal
  4. Insufficient heat input Settings

Stainless steel stick electrodes

Electrodes: E308L-16, E309L-16, E316L-16, E310-16, E312-16

  1. Moisture in electrode coating
  2. Contaminated base metal or carbon steel contamination
  3. Arc length too long

Stainless MIG/TIG wire

Electrodes: ER308L, ER309L, ER316L

  1. Insufficient gas coverage or wrong gas
  2. Carbon steel contamination
  3. Moisture or contamination on base metal

TIG filler rod (manual feed)

Electrodes: ER70S-2

  1. Insufficient gas post-flow Settings
  2. Contaminated base metal or filler
  3. Gas flow too low or cup too small
  4. Tungsten contamination (dipped in puddle)

Undercut

What it looks like: Groove or notch running along the toe (edge) of the bead, like a ditch beside a road.

A groove melted into the base metal along the edge of the weld that wasn't filled by weld metal.

Common causes (all processes): Amperage too high. Travel speed too fast. Incorrect electrode angle. Arc length too long.

Causes by electrode type (5 types covered)

Cellulosic (deep penetration)

Electrodes: E6010, E6011

  1. Amperage too high for material thickness Settings
  2. Not pausing at the toes during weave

Low-hydrogen (code quality)

Electrodes: E7016, E7018, E7018-1

  1. Amperage too high Settings
  2. Travel speed too fast with weave technique

Solid MIG wire (gas shielded)

Electrodes: ER70S-6, ER70S-3, ER80S-D2

  1. Voltage too high Settings
  2. Travel speed too fast
  3. Gun angle pushing puddle away from toes

Self-shielded flux-core wire

Electrodes: E71T-11, E71T-GS, E71T-8

  1. Voltage too high Settings
  2. Travel speed too fast on vertical welds

Aluminum MIG/TIG wire

Electrodes: ER4043, ER5356, ER4047

  1. Too much heat melting the thin oxide-free edges Settings

Excessive Spatter

What it looks like: Tiny balls of metal stuck to the surface near the bead. Ranges from a few dots to a heavy coating.

Small metal droplets scattered on the base metal around the weld.

Causes by electrode type (4 types covered)

Cellulosic (deep penetration)

Electrodes: E6010, E6011

  1. Normal for this rod type
  2. Amperage too high Settings
  3. Arc length too long

Low-hydrogen (code quality)

Electrodes: E7016, E7018, E7018-1

  1. Arc blow (magnetic deflection)
  2. Moisture in the rod
  3. Amperage too high Settings

Solid MIG wire (gas shielded)

Electrodes: ER70S-6, ER70S-3, ER80S-D2

  1. Voltage too low for wire speed Settings
  2. Using 100% CO2 shielding gas
  3. Stick-out too long
  4. Dirty base metal

Self-shielded flux-core wire

Electrodes: E71T-11, E71T-GS, E71T-8

  1. Voltage too high Settings
  2. Wrong polarity Settings
  3. Normal for process

Burn-Through

What it looks like: Hole in the plate or visible sagging/drooping through the back side.

The arc melts completely through the base metal, leaving a hole.

Common causes (all processes): Amperage too high for material thickness. Travel speed too slow. Gap too wide between pieces. Wrong rod diameter (too large).

Causes by electrode type (3 types covered)

Aluminum MIG/TIG wire

Electrodes: ER4043, ER5356, ER4047

  1. Heat input too high for aluminum's low melting point Settings
  2. No backing or heat sink

Rutile / Titania (smooth, easy arc)

Electrodes: E6012, E6013, E7014, E7024

  1. Rod diameter too large for material Settings

Solid MIG wire (gas shielded)

Electrodes: ER70S-6, ER70S-3, ER80S-D2

  1. Wire feed speed (amperage) too high Settings
  2. No skip-welding or stitch pattern

Lack of Fusion / Cold Lap

What it looks like: Bead looks stacked on top of the plate. A visible line between the bead edge and base metal. Bead may peel off with a hammer.

Weld metal sits on top of the base metal without actually melting into it. The bead rolls over the edge without bonding.

Common causes (all processes): Amperage too low. Travel speed too fast. Wrong electrode angle. Heavy mill scale or contamination.

Causes by electrode type (3 types covered)

Low-hydrogen (code quality)

Electrodes: E7016, E7018, E7018-1

  1. Amperage too low for the rod diameter Settings
  2. Wrong rod angle on multi-pass welds

Solid MIG wire (gas shielded)

Electrodes: ER70S-6, ER70S-3, ER80S-D2

  1. Voltage too low (cold weld) Settings
  2. Push angle too steep, blowing puddle ahead of arc

Aluminum MIG/TIG wire

Electrodes: ER4043, ER5356, ER4047

  1. Oxide layer preventing fusion
  2. Insufficient heat input (heat sinks away too fast) Settings

Cracking

What it looks like: Line or fracture in or near the bead. May be longitudinal (along the bead), transverse (across it), or crater (at the stop point).

Visible crack in the weld bead, at the toe, or in the heat-affected zone. Can appear immediately or hours/days later.

Causes by electrode type (4 types covered)

Low-hydrogen (code quality)

Electrodes: E7016, E7018, E7018-1

  1. Hydrogen cracking (moisture in rod)
  2. No preheat on thick or high-carbon steel
  3. Crater crack at stop points
  4. High restraint (parts can't move)

Cellulosic (deep penetration)

Electrodes: E6010, E6011

  1. Hydrogen cracking on susceptible steel
  2. Crater cracking

Aluminum MIG/TIG wire

Electrodes: ER4043, ER5356, ER4047

  1. Hot cracking (wrong filler alloy)
  2. Crater cracking
  3. Insufficient heat input on thick sections Settings

Stainless steel stick electrodes

Electrodes: E308L-16, E309L-16, E316L-16, E310-16, E312-16

  1. Too much heat input (sensitization/hot cracking) Settings
  2. Wrong filler for the base metal

Slag Inclusion

What it looks like: Dark spots or lines in the bead after slag removal. Slag that won't come off cleanly. Bead surface may be uneven.

Slag trapped inside the weld bead, visible as dark spots or lines when you chip and brush.

Causes by electrode type (3 types covered)

Low-hydrogen (code quality)

Electrodes: E7016, E7018, E7018-1

  1. Not cleaning slag between passes
  2. Welding over undercut or irregular bead profile
  3. Amperage too low or incorrect angle Settings

Cellulosic (deep penetration)

Electrodes: E6010, E6011

  1. Travel speed inconsistent
  2. Not cleaning between passes

Self-shielded flux-core wire

Electrodes: E71T-11, E71T-GS, E71T-8

  1. Wrong travel direction for position
  2. Not cleaning between passes

Bad Bead Profile

What it looks like: Tall, crowned bead that looks like a rope laid on the joint. Or overly flat, spread-out bead. Or bead that's concave (dished in the middle).

Bead is too tall and narrow (ropy), too flat and wide, concave, or has an irregular shape.

Common causes (all processes): Voltage/amperage imbalance. Travel speed wrong. Wrong technique for the rod type.

Causes by electrode type (3 types covered)

Cellulosic (deep penetration)

Electrodes: E6010, E6011

  1. Whip technique too aggressive or inconsistent

Iron powder (high deposition)

Electrodes: E7014, E7024, E6020

  1. Trying to weave instead of drag

Solid MIG wire (gas shielded)

Electrodes: ER70S-6, ER70S-3, ER80S-D2

  1. Wrong transfer mode for the application Settings

Related Resources

All Welding Electrodes

Amperage charts, specs, and application guidance for 30 consumables.

Electrode Comparisons

Side-by-side comparison tables to choose between similar rods.

Which Rod for My Job?

Application guides matching your job to the right electrode.