I cut tin with a shear, left hand, right hand, and straight snips. I would reccomend a mig welder for doing the welding. Lots of good products out for treating rust, I use one called Phix, available at a lot of parts stores. Not sure on the blasting, I have a guy do mine and all I now is that he doesn't use sand on tin and he doesn't warp panels. Hope this helps a bit, others will be along with more and better answers.