Mig Tech question

What is the technical reason for not being able to weld thick metal with a mig?

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Here is the reason.

There are 2 types of MIG welding used frequently.

short circuit mig, and spray.

a 3rd type is called globular and almost no one uses it.

the type you are probably referring to is called short circuit mig...also called short arc.

It is the type of mig welding used for general fab work for everything from auto body panels to chassis work and also for general fabrication.

Its a great process and is very versatile but is not used much for structural work like bridges , buildings, and ships, because it is way more likely to have cold lap than stick, flux core, or spray transfer mig.

That brings me to the second type of mig that is used frequently...spray transfer also known as spray arc.

spray transfer requires different gas than short circuit and it much hotter and less likely to cold lap.

There were a few instances of weld failures back in the day that caused welding engineers to impose additional and strict testing requirements on short circuit mig welding.


Thats the reason.

It is not that it wont work, its just that in the hands of the wrong welder, welds can easily have cold lap and fail....even though the welds look fine.