Question: what is the difference between a 1st and 2nd class welder?
Answer: 1st class welders are those coded eg to Asme etc or in Oz they have certification scheme called AS 1796 part 1 to 9. Which is harder than ASME, but once passed it is valid for life. 2nd class welders are general welders who have served their time (or not) or fabricators but have no codings or certification.