MIG Welding Interview Questions ,How I Passed My Interview

I still remember the first time I sat in front of a hiring supervisor for a MIG welding job. My hands were steady when I weld but during that interview, I had no idea what to say. I knew how to run a proper bead, I knew my voltage and wire speed, I had worked fabrication for years — but the moment the supervisor asked me "what shielding gas do you use for MIG welding and why," I went blank for a few seconds.

That day I did not get the job 😢.

Not because I could not weld. Because I was not prepared for the questions. After that experience, I made a list of every question they asked me and started preparing properly. The next interview I cleared on the first attempt. So here I am sharing everything — every MIG welder interview question, what the supervisor actually wants to hear, and how I answered them.

Why MIG Welding Interviews Are Different From Other Trade Interviews

Most people think welding interview means just a trade test. Show up, weld a bead, pass the test, get the job. That is not how it works in good companies. Especially in fabrication shops, manufacturing units, and overseas projects — the supervisor will sit with you for 15–30 minutes before the practical test and ask technical questions.

My foreman once told me — "We already know you can hold a torch. We want to know if you understand what you are doing." That line explains everything about how welding interviews work.

Most Common MIG Welding Interview Questions and How to Answer Them

1. Tell me about your MIG welding experience

This is always the first question. And most welders waste it by saying something like "I have 5 years experience." That is not enough.

What they actually want: Specific projects, materials, positions, and any challenges you handled.

How I answered it: "I have worked on structural fabrication jobs welding mild steel from 3mm to 12mm plate thickness. I have experience welding in flat, horizontal, vertical, and overhead positions. In my last job, I was responsible for tack welding and full-pass welding on pipe spools under WPS guidelines."

Mention WPS. Mention positions. Mention materials. Supervisor will immediately know you are a real welder.

2. What shielding gas do you use for MIG welding?

This is one of the most common MIG welding technical interview questions and many welders fumble here.

Correct answer:

• For mild steel — 75% Argon + 25% CO2 (C25 mix) is standard. Gives good arc stability and less spatter.
• For pure CO2 — cheaper option, more spatter, deeper penetration, used in heavy structural work.
• For stainless steel — 90% Helium + 7.5% Argon + 2.5% CO2 or tri-mix gas.
• For aluminium — 100% pure Argon.

I made a mistake in my first interview — I said "Argon gas" without explaining the mix. The supervisor asked follow-up and I could not answer. So prepare the full answer, not just one word.

3. What is the difference between MIG and TIG welding?

Almost every interview asks this. Keep it simple and practical.

My answer: "MIG welding uses a continuously fed consumable wire electrode with shielding gas. It is faster and suited for thicker materials and production work. TIG welding uses a non-consumable tungsten electrode and separate filler rod — it gives cleaner, more precise welds, better for thin materials and stainless steel. I have experience with both but MIG is my primary process."

If you want to understand this difference more deeply before your interview, our detailed guide on MIG Welding vs TIG Welding – Key Differences Explained will help you prepare a strong answer.

4. How do you set up voltage and wire speed on a MIG machine?

This question separates experienced welders from beginners. When I faced this question, I was confident because I had made enough mistakes on machines to know exactly what to say.

My answer: "Sir I start by checking the material thickness and selecting the correct wire diameter — usually 0.8mm for thin material and 1.0mm or 1.2mm for heavier plate. Then I set voltage and wire feed speed according to the WPS or manufacturer chart on the machine door. For 6mm mild steel I typically run around 22–24 volts with wire speed around 5–6 m/min. I always do a test run on scrap plate first and listen to the arc sound — a smooth frying bacon sound means the settings are correct."

That "bacon sound" line — supervisors love it. It shows you actually welded, not just read about it.

For detailed settings reference, check our guide on MIG Welding Settings – Voltage and Wire Speed.

5. What welding defects have you encountered and how did you fix them?

This is where your real experience shows. Do not say "I never made mistakes." No supervisor believes that.

My answer: "I have dealt with porosity, undercut, and incomplete fusion at different points. Porosity usually happened when gas flow was too low or there was moisture on the base metal — I learned to always check gas flow before starting and grind the surface clean. Undercut happened when my travel speed was too fast or voltage too high — I slowed down and adjusted settings. My QC inspector rejected one of my joints early in my career because of lack of fusion on the root — that was the day I learned to properly check fit-up and bevel angle before welding."

Mention your QC inspector. Mention what you learned from the rejection. This shows E-E-A-T — real experience, real lessons.

6. How do you read a WPS?

WPS (Welding Procedure Specification) knowledge is mandatory for any serious welding job. If you say "I don't know WPS" in an interview, you will not get the job in any reputable company.

My answer: "WPS tells me the approved welding process, base material, filler material, preheat requirements, interpass temperature, joint design, and post-weld requirements. Before starting any weld, I check the WPS for current range, voltage, wire speed, and travel speed. My foreman always said — if WPS says something, follow it exactly. No shortcuts."

7. What PPE do you use during MIG welding?

Safety question is always there. Keep it practical, not textbook.

My answer: "Auto-darkening welding helmet, leather welding gloves, flame-resistant jacket, safety boots, and ear protection if working in a loud area. I also make sure ventilation is proper before starting — MIG welding fumes can be harmful especially in enclosed areas. I check my gas hose connections for leaks before every shift."

Never say "dangerous" in interviews or on the job — use "hazardous" or "harmful" instead. It sounds more professional.

Interview Questions Table – Quick Reference

What I Did Before My Interview — Practical Preparation

After failing my first interview, I did these things before the next one:

• Revised all shielding gas combinations — mild steel, stainless, aluminium
• Practiced explaining voltage and wire speed settings out loud to myself
• Memorized common weld defect causes — porosity, undercut, spatter, incomplete fusion
• Reviewed one WPS document I had from my previous job
• Prepared a real story about a welding mistake I made and what I learned

That last point was the most important. When the supervisor asked "Tell me about a mistake you made on the job" — I had a real answer. Not a fake one. Real industry experience is what EEAT is all about, and supervisors can tell the difference immediately.

Trade Test Tips After the Interview

Most MIG welding jobs have a practical trade test after the verbal interview. Here is what I always do:

• Check gas flow first — 15–20 LPM for mild steel MIG
• Inspect wire spool and liner condition
• Run a short test bead on scrap to check machine settings
• Clean base metal with grinder before welding
• Maintain consistent travel speed — do not rush
• Listen to arc sound throughout — any irregular popping means check settings

My supervisor once told me — "I watch how a welder sets up his machine before he even strikes the arc. That tells me everything."

FAQ - HR Asking Question 

Q: What is the most important thing in a MIG welding interview? Showing real practical knowledge — not just saying you can weld but explaining how you set up the machine, what problems you faced, and how you solved them.

Q: Do I need AWS certification to pass a MIG welding interview? Not always, but AWS certification strengthens your application significantly. Many companies conduct their own trade test. Certification shows you met a formal standard.

Q: What shielding gas question is most commonly asked in MIG welding interviews? "What gas do you use for mild steel MIG welding?" — Answer is 75% Argon + 25% CO2 (C25 mix).

Q: Should I mention welding defects in my interview? Yes — absolutely. Mentioning defects you encountered and how you corrected them shows real experience. Supervisors trust welders who are honest about their learning process.

Q: How long does a MIG welding interview typically last? Usually 15–30 minutes for the verbal part, followed by a 30–60 minute practical trade test on site.

Conclusion

Passing a MIG welding job interview is not just about your hands — it is about how clearly you can explain what your hands know. In my experience, supervisors are not looking for perfect textbook answers. They want a welder who has actually stood in front of a machine, made mistakes, fixed them, and understands why things went wrong.

Prepare your real stories. Know your shielding gases. Know your defects. Know your WPS. And walk into that interview like you have already done this job many times — because if you have real welding experience, you actually have.