Detaching the bottom section of a '30 A rad. shell

How to do without damage? I really need to separate it from the sides so some cosmetic repairs to one side and the bottom can be done properly. I'm pretty good at straightening and polishing stainless but really am not sure how to get this apart. I'd assume a good welder with the proper equipment can rejoin it later, right? Thanks for any insight.

 

Anyone on the day shift perhaps?

 

The lower apron is spot-welded to the sides.