Tinsel strength hehehehehe.
Sorry.
I was always amazed people were able to abrade through the very hard anodized oxide layer with leather toestraps. Of course given most bikers' preoccupation with reducing friction, I always wondered about people that set up their bikes so their toestraps are dragging across their crankarms every revolution. I'm sure you've seen those crankarms with the big grooves worn in them from soft leather toestraps, Imagine the wasted pedaling energy that represents!
One can very easily strip the oxide layer off of anodized parts using a basic compound like oven cleaner. If one then polishes out any scratching and marring on the surface and reanodizes undyed over the bright polished surface one can get the exact same hard satin finish Campagnolo parts had new, so even a perfect satin anodized finish is no guarantee the part hasn't been refurbished from a poor prior state.
Kurt Sperry Bellingham, Washington USA
On Thu, Apr 1, 2010 at 4:59 PM, verktyg <verktyg@aol.com> wrote:
> The satin anodized finish was always one of the charms of Campagnolo
> components. Same thing with Cinelli bars and stems.
>
> The thin anodized layer covers soft aluminum which can still be easily
> scratched or gouged. That's one of the downsides because the damage stands
> out against the satin finish.
>
> The anodized finish is composed of aluminum oxide with a Knoop hardness of
> 2100+. This is much harder than most abrasives used to polish aluminum
> except silicon carbide with a Knoop hardness of ~2500 (diamond is 4-10 times
> harder).
>
> The harder anodized layer resists the abrasive cutting action of most
> polishing compounds which can result in much faster removal on any uncoated
> aluminum surfaces resulting in a shiny but uneven finish.
>
> Without getting into how Velo-mine gets around this problem, I wonder how
> much base aluminum gets removed with a corresponding loss of detail?
>
> I think it's fine for an owner to customize their parts anyway they want.
>
> But... I too am leery of buying "crow bait", bright shiny objects (that
> maybe shouldn't be bright and shiny).
>
> On the technical side of things, sometimes polishing is used on highly
> stressed parts to help prevent cracks and stress risers. When testing
> material tinsel strength, there can be a significant difference in strength
> between a polished and non-polished test specimen.
>
> So... It's a long shot, but polishing old Campy cranks could possibly
> prevent breakage! YMMV ;-)
>
> Remember, paint can hide a multitude of sins!