MIG Welder Interview Questions
& Model Answers, 2026

Short circuit transfer runs at low voltage and current, works out of position and on thin material, and carries the highest lack-of-fusion risk on heavy sections. Globular is an uncontrolled in-between mode most welders avoid. Spray transfer needs high argon content and higher voltage, gives deep penetration and high deposition but is essentially flat and horizontal only. Pulsed spray gives spray-like quality at lower average heat and can be run out of position. Naming the lack-of-fusion risk in short circuit is what marks out a real welder.

Carbon steel commonly runs argon with a carbon dioxide addition, or straight carbon dioxide for deep penetration and more spatter. Stainless uses argon with a small oxidising addition such as a couple of percent oxygen or carbon dioxide, kept low so the corrosion resistance and the bead chemistry are not compromised. Aluminium requires pure argon, or an argon-helium mix for thicker sections. Say that flow rate matters as much as mix, and that too much flow causes turbulence and draws in air.

Work the list in order of likelihood: gas coverage first — flow rate, a leaking hose, a blocked or spattered nozzle, a draught or fan blowing the shield away — then contamination on the base metal such as oil, paint, rust, moisture or galvanising, then the consumable itself, then technique such as too long a stick-out or too steep a drag angle. Say you would run a test coupon after each change rather than adjusting three things at once.

Start from the wire manufacturer's chart or the welding procedure for that wire diameter and material thickness, set wire feed for the amperage you need and voltage for the arc length and bead profile, then tune by sound and bead appearance — a smooth crackle for short circuit, a steady hiss for spray. Keep the stick-out consistent because it changes the effective current. Say that you record the settings so the weld is repeatable rather than rediscovered every shift.

Identify the reference line and the arrow, and know that symbols below the line apply to the arrow side and above it to the other side. Read the weld type from the symbol shape, the size to the left, the length and pitch to the right, and note tail information for the process or specification, plus field weld and weld-all-around indicators. A welder who cannot read the symbol will weld the wrong side or the wrong size and it will fail inspection.

A WPS states the essential variables — process, base metal group, filler and gas, thickness range, position, preheat and interpass temperature, and the electrical parameters — that the qualification test proved. Welding outside those variables means the weld is not qualified, which on code work makes it rejectable regardless of how it looks. Say that if the WPS does not fit the job, you raise it with the welding engineer rather than adjusting the parameters yourself.

Give the actual defect and the actual cause: undercut from too much voltage and travel speed, lack of fusion from short circuit on heavy plate, porosity from a draught, or a bead profile that would not pass. Describe how you corrected it, whether you had to gouge and rewelded, and what you changed in your setup. Welders who have never had a weld rejected are either unqualified or not being inspected.

The credible version describes preparation — fixtures, fit-up, cleaning, consumables and settings ready — rather than welding faster. Add how you handled the shift where the rate could not be met without cutting corners, and that you said so rather than shipping bad welds. Shops lose far more to rework than to a slightly slower welder.

Gaps outside tolerance, misalignment, wrong material, missing bevel or a joint that will not be accessible once tacked. Describe raising it with the fitter or the supervisor and getting it corrected rather than filling a bad gap with weld metal. Filling a gap is the single most common way a welder turns a fit-up problem into their own quality failure.

Concrete practices: correct shade lens and full PPE including flame-resistant clothing, welding screens so nobody nearby gets flash burn, local exhaust or respiratory protection for stainless and galvanised material, checking for combustibles and having a fire watch, verifying cylinder security and regulator condition, and never welding on a sealed or previously-contained container. Mentioning hexavalent chromium and galvanising fume shows real awareness.

Anchor to the published series: the BLS OEWS May 2025 national median for welders, cutters, solderers and brazers is $53,750 a year ($25.84/hr), with the top 10% above $77,530. That covers production welders through code welders across many industries, so place yourself by what you can prove — which processes, positions and codes you are qualified in, and whether you can pass a test on the shop's material and procedure.

Ask whether the shop runs shift differentials, whether there is a production bonus and what it is measured on, and crucially how rework is treated — a piece rate that pays for output but not for repairs pushes welders toward speed over quality. Also ask about guaranteed hours, because welding demand is cyclical and a slow quarter changes the annual figure more than the base rate does.

Employer-paid qualification testing and continuity, PPE including a good helmet, jacket and gloves supplied rather than bought, respiratory protection and fit testing where the material requires it, boot allowance, and training toward additional processes or positions. Ask whether the shop pays for the time spent taking and renewing weld tests, since that is real earning time.