I don't get it. Apart from the production line welding where pushing a button makes a robot weld, doesn't that someone who actually has to HOLD a gun/stinger/torch and decidedly put a weld down need certification?
I dont think i've ever seen a job ad claiming "no problem, we'll teach you to weld in 8 minutes"
and while we're on the subject.. how do professional weldors know THEIR mig welds are sound? you can't test EVERY bead you lay down. a good looking weld is a good looking weld.
i run a small job shop and have 2 other weldors in house. most of the 'non critical' work that comes through is theirs.. everything else is mine. now, maybe i can spot whether or not a puddle/bead wets both pieces.. maybe i can read cluses when its not deep/strong/big/hot enough, that the others might not catch. (for the simple fact, perhaps, that they haven't been doing it as long).
but most of the time its based on looks, feel, and 'intuition' i suppose. i know my machines. i know what they can and can't do. i know what _I_ can and can't do. however, i have NO clue, just by looking, if a mig weld has ABSOLUTELY withoutadoubt fused both, or more, pieces. and i can't always do destructive testing. though we run test pieces when we can, that get sawn and inspected, that isnt always the case.
in that respect, why couldnt any (mig) weldor be put in the same category as trailer-make'n-newbie? granted the odds are less, but your trailer could fall apart, your bridge could fall down, etc.
-tony