Flux core wire feed .. "Body Work"?

Flux core wire is better used on heavier welding applications. The heat required for fluxed wire is greater and will impart much greater warpage to your body panels. One thing that will help you is to lay cold, wet rags close to your weld area to prevent the heat from migrating through your panels and limit the heat distorted areas. A MIG running .024 hard wire is a much better choice for your application.

If i were you i'd use the mig. the flux has so much more heat. it'll warp your body. look pretty crappy unless your really know what you're doing.

A good welder can make either one work. I have a flux core welder and do not have a problem, You just have work slower.

It will work but don't expect it to be pretty. Should be fine for what you are looking for.

You'll just have to chip the slag off.

it works, but theres a lot more cleanup.