snip
I hope that you didn't use a steel wire brush to strip the corrosion. The
steel wires of the brush embed into the aluminum and the dis-semilar metals
start electrolysis (corrosion).
snip

I used a flexible, aluminum oxide coated, nylon abrasive wheel for most of
it. I did use a brass wire brush for some of the nooks and crannies around
the box itself. Brass is a dissimilar metal, does it cause the same problem
as steel?

Eddie
N40008