Anybody who has owned aluminum bodied cars with steel frames can relate to this. I could tell you horror stories about a certain '66 Land Rover whose aluminum body rotted from the bottom up, even with a thin buffer of felt between body and frame. Then there was my BIL who shimmed a scope base with a piece of soda can- the giveaway was the rust we saw creeping out from under the base.

"You can lead a man to logic, but you cannot make him think." Joe Harz
"Always certain, often right." Keith McCafferty