Enoch,look up recent(last 2/3 months) discussions on this one.
If you are already a competent arc welder then arc welding is in my view the best and cheapest way to go.
Regarding Caterpillar tractors,I am a little out of date these days but there are at least 4 different MIG welding systems and they probably use "globular transfer" which is NOT the same as your ordinary MIG home system.
I used it over 40 years ago and thick plates melt like butter.but go back and look up past discussions on this,lots of good info and a few good laughs as well!!! David
