: I never thought of the shellac...and yeah, it would be cheaper. You
: know far better than I do, so I should take your advice! I do
: expect to be posting on here and making phone calls during the
: build, so I should listen to the guys that do it more often than
: me

Plywood should be fine as is, shellac will slow down but not stop moisture movement. Steel would be a lot cheaper than ally but a beast to drill if you don't have any cutting oil . . . good luck with whatever you decide to use!