Four years ago I used treated lumber for a transom for my old 14 foot jonboat. I used the pine boards that is used for decking. I have been told that it causes the aluminum to corrode, but have seen no visible signs of it. What should I look for? I am in the process of taking these boards off and replacing them. I can't see any damage but I don't really know what to look for? any help would be appreciated-p-