My buddy is a mechanical engineer. He absolutely swears that on dark cars you will eventually see the mig lines if you use a mig. I have personally never experienced it.
You are 110% correct, your buddy is not. Next time you see your buddy ask him if he knows what a Metallurgist is? Ask Him what part of Physics and Math is related to fusion of metal? Ask him what the "70" means in a 7018? Pass this on to him if he thinks you are a "know-it-all":
MetallurgyPretty dry stuff which is why I switched from Metallurgy and welding to Environmental Sciences.
Final word on this: Most of this topic is really just poor body work and poor welding skills.
