OK, to re-open the idea another ChemE buddy came back to me this morning and he agreed that if you use a tinning flux that gets into the rolled joint, then tin the seam and lead over it the base metal should corrode only slightly because once the loosely bonded oxygen is used up in the flux there's no more free oxygen to feed corrosion. I think that you'll be fine tinning your joint, then leading it closed which will encase any remaining acids. In fact, I think that the heat from leading the joint will quickly cook out the joint, eliminating future corrosion from consideration. Just my $0.02.