I have two problems with coating over chrome. The ideal surface for any powder is the media blasted, bare, spotlessly clean substrate metal. Blasting a good, triple-plated chrome job to provide for adequate powder "tooth" and longevity is tedious enough just to etch it let alone completely remove it. Of course, powders could be applied on the chrome as is but it will not last for decades ... so I don't do it that way.
One also has to presume that the chrome job is going to stay put. The important thing to remember about pot metal is that you never know what exactly is in it, as it's made from all the steel plant leftovers on any given day. Any dissimilar metals are going to want to separate from each other over time (as evidenced by all the pitting and deterioration on our old pot metal consoles, light housings, emblems, antenna bases, door handles, etc.), and that can cause the chrome to start coming off in sheets. When it does, it will take my powder job right along with it.
