Originally Posted by wirejock
I'm no chemist but my understanding is the Aluminum Oxide layer must be removed so the Alodine can convert the pure aluminum to Aluminum chromate which doesn't oxidize. Stable surface. Also prepped for paints.
I could be way off base.
If the alodine conversion is aluminum oxide to aluminum chromate, then we are taking a layer of what presumably is already weakened material and converting it to presumably equally weakened material. Whereas if the alodine conversion is pure aluminum to aluminum chromate, then we have weakened the part in the alodining process. Although perhaps you could look at it as the etching is what really did the weakening, because if we didn't alodine after etching, that same layer the alodine would be converting would instead oxidize.
Since Vans obviously supports priming components, and as far as I understand it, etching is a prerequisite to priming regardless of whether you use alodine, it seems fair to assume that whatever weakening is occurring due to etching, however negligible or significant & measured that it is, is within the design intent of Vans.
Thus I would conclude that there is not a concern here at all to my #2 question.
I'm still curious what the actual chemical process is doing and which of these two seemingly conflicting explanations is actually correct.