>From an engineers point of view, anodizing is to reduce corrosion first and for appearance second. Not all aluminium alloys are equally corrosion resistant. In particular, 6061 is quite good and is the default selection for high quality parts because it is the best balance of mechanical, corrosion and producibility properties. 7075 (ergal more or less) and 2024 alloys, which have higher mechanical strength are more subject to corrosion (and distort more when machined). A
t least the Campagnolo chainrings and probably the cranks are ergal (7075 like) so it is natural to anodize them. So that gets us that far. Does anyone know the alloys for the various parts on Chuck's list?
Joe Bender-Zanoni 2 feet of snow at the topof First Watchung mountain, Great Notch, NJ
> There seems to be lots of confusion on just which aluminum parts in a
> Nuovo or Super Record are anodized. This comes up when questions about
> how best to clean the parts when finding an old bike.
>
> First, some anodizing info...
>
> Definition:
> Anodizing is the successful development and control of a natural
> oxidation process that occurs when aluminum is exposed to the
> atmosphere. Electricity and chemicals are used jointly to produce a
> hard, transparent surface that is integral with base aluminum.
>
> Anodizing Basics:
> Aluminum is anodized for corrosion resistance, abrasion resistance,
> insulation from electricity, adhesion, or aesthetic enhancement.
>
> Characteristics:
> . Hard, comparable to a sapphire
> . Transparent, similar to glass
> . Insulative and static-resistant
> . Wide variety of colors and finishes
> . Integral with aluminum surfaces, non-flaking
>
> Now, which aluminum parts are anodized and which aren't:
>
> Hubs - no
> Pedal bodies - no
> Pedal cages - yes
> Headset - yes
> Rear derailleur - yes
> Front derailleur - no
> Cranks - yes
> Chainrings - yes
> Brake levers - yes
> Brake calipers - yes
> Shift levers - no
> Seat post - no
>
> Incidentally, when the Super Record group first made the rounds of the
> trade shows circuit, the head set, chainrings, and bottom bracket cups
> were black anodized. The production versions were clear anodized.
>
> The non anodized parts can be cleaned and polished (and protected) with
> Semichrome, Wenol, Mothers, etc.
>
> The anodized parts can be cleaned with degreaser, solvent, WD-40, soap
> and hot water, etc.
>
> A simple test to see if an aluminum part is anodized or not. Put a
> little dab of Semichrome (my personal favorite) on a white cloth and rub
> the part a little. If there is a black deposit on the cloth that means
> that there has been a chemical reaction with the aluminum. If the part
> is anodized, there will be no change in the polish on the cloth because
> there has been no reaction (and absolutely no damage to the anodizing).
>
> Now the QUESTION: Why are some of the parts anodized and some are not?
> Class? Anyone?
>
> Chuck Schmidt
> South Pasadena, Southern California
> http://www.velo-retro.com (Campagnolo Timeline, reprints & t-shirts)
>
> .