Well,lets put it this way
,I have welded pipe with mig that has passed bend and tensile tests,with .035 wire about 120 amps or so,I was a stick welder,than worked for a guy who wanted to start welding some stuff with mig[short circuiting],so I had to figure out how this thing worked,took me a quite awhile and several failed attemps to get it,
So,,from experience can tell you mig has a big problem with cold lap and lack of fusion at around those amps[you can't weld pipe in postion at much higher amps than that],so considering your average newbie/back yard type has less experience at welding than I did when I first started trying it,would not recommend it for anybody who wants to weld something other than thin stuff,he ain't going to be running high amps,he won't know the tricks to get the weld to fuse at lower amps.
Generally on thick stuff in these fab shops they use flux core or subarc,from my experience. But guess not all,in a bridge shop you won't see them welding the thick stuff with short circuiting mig,know that from having inspected in them for a few years
So,,from experience can tell you mig has a big problem with cold lap and lack of fusion at around those amps[you can't weld pipe in postion at much higher amps than that],so considering your average newbie/back yard type has less experience at welding than I did when I first started trying it,would not recommend it for anybody who wants to weld something other than thin stuff,he ain't going to be running high amps,he won't know the tricks to get the weld to fuse at lower amps.
Generally on thick stuff in these fab shops they use flux core or subarc,from my experience. But guess not all,in a bridge shop you won't see them welding the thick stuff with short circuiting mig,know that from having inspected in them for a few years