I need some advice on purchasing a welder. I have some experience in ornamental iron work using electric arc welders. Unfortunately, no experience with a MIG or TIG welder.

In the near future, I would like to do some rust repair on my old truck and some other general repair work. I will typically be working with sheet metal up to 3/8 inch thick metal. Occasionally, there may be some projects with thicker metal, perhaps a 1/2 to 3/4 of an inch thick.

So, I have a few questions:

1. How important is the duty cycle of a MIG welder when welding sheet metal? I'm assuming that only short welds can be made on sheet metal anyway. (A long weld would cause the metal to warp.) If this is correct, would duty cycle be relatively unimportant when welding sheet metal?

2. How does the operating costs of a MIG welder compare with an arc welder?

My current thinking is to buy a lower priced brand name MIG welder and an arc welder. Not sure if this is the best plan though. Anyone have any advice?