Welder interview questions and sample answers

A welder interview usually mixes two kinds of question: ones that test whether you know the job, and behavioral ones that ask for proof from your past. Below are 10 of the first with a short model answer, and 5 of the second with what the interviewer is really checking. Rewrite every answer in your own words and with your own numbers.

Job-specific questions

1. How do you choose between MIG and TIG for a job?

I use TIG for thin material, aluminum, or where a clean cosmetic weld matters, like stainless handrails. MIG is faster for thicker steel and production work where speed matters more than appearance.

2. What's your process for setting up a weld procedure on structural steel?

I follow the WPS provided by the engineer, matching amperage, travel speed, and electrode type, and I run a test coupon first to confirm penetration before welding the actual joint.

3. How do you prevent warping on thin sheet metal?

I use lower amperage, skip weld in short segments across the piece instead of one continuous bead, and clamp the material to a heat sink or fixture to control distortion.

4. How do you check a weld for defects after finishing?

I do a visual inspection for undercut and porosity first, then use dye penetrant testing on critical welds, and I've worked jobs requiring X-ray or ultrasonic testing for code welds.

5. What's your approach to welding in an overhead position?

I reduce amperage from flat position settings, use a shorter arc length, and move faster to control puddle sag. I prefer a slight whipping technique to avoid excess buildup dripping.

6. How do you select filler metal for stainless steel?

I match the filler to the base metal grade, commonly 308L for 304 stainless, and use back purging with argon on pipe welds to prevent sugaring on the inside of the joint.

7. What safety steps do you take before welding in a confined space?

I test the atmosphere for oxygen and gas levels, set up ventilation or an exhaust fan, use a fire watch, and confirm a spotter is present per OSHA confined space rules.

8. How do you handle a weld that fails inspection?

I grind it out completely rather than welding over it, identify the root cause like wrong heat input or contamination, and re-weld following the corrected procedure before calling the inspector back.

9. Describe your process for tacking before a full weld.

I place tacks at intervals matching material thickness, usually every 4-6 inches on structural steel, checking alignment and gap with a square before running the final pass.

10. How do you weld dissimilar metals like steel to stainless?

I use a nickel-based filler rod like ENiCrFe-3 to handle the differing thermal expansion rates, and I control heat input carefully since stainless conducts heat differently than mild steel.

Behavioral questions

Answer these with STAR: the Situation in one sentence, the Task, the Action you took (most of the answer), the Result with a number.

11. Tell me about a result you are proud of.

What they are checking: A specific outcome with a number, and what you personally did to get it.

A result to build the answer around: Weld structural steel and pipe with a 99% X-ray pass rate over 3 years.

12. Describe a time you improved how something was done.

What they are checking: That you notice waste and fix it without being told, then measure the difference.

A result to build the answer around: Fabricated components for 30 commercial buildings and 2 bridges.

13. Tell me about a time you had to deliver under pressure.

What they are checking: How you prioritise, communicate early and still finish to standard.

A result to build the answer around: Helped cut rework on the shop floor by 40% by standardizing fit-up checks.

14. Give an example of working with a difficult colleague or customer.

What they are checking: Calm, the other person's view stated fairly, and a result that helped both sides.

A result to build the answer around: Read blueprints and weld symbols to build assemblies without supervision.

15. What is something you learned from a mistake?

What they are checking: Ownership without excuses, and the habit you changed so it did not happen again.

A result to build the answer around: Zero lost-time injuries across 6 years.

Before the interview

Interviewers read your resume just before they walk in, and most questions come from it. Every bullet on it should be one you can expand into a two-minute STAR story. Check that it matches the posting with the free ATS Match Score, and look at the welder resume keywords the ad is likely to use.

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