Anodising is ok in small amounts on a bike and let`s face facts , you can buy stuff already Anodised nowadays .... If I remember rightly it`s best to start off with a totally clean and freshly machined bit of Ally anyway before any serious Oxidising takes effect ..... so Anodising old scruffy parts could be a recipe for disaster , I may be wrong though ........ that needs researching
Would be nice to be able to anodise massive things like frames and wheels but there is probably a massive problem with doing it as not many do