Re: [CR] black rims...

(Example: Framebuilders:Tony Beek)

Date: Thu, 3 Sep 2009 10:50:44 -0700
From: "verktyg" <verktyg@aol.com>
To: <hsachs@alumni.rice.edu>, <Classicrendezvous@bikelist.org>
References: <4A9F9DEF.5070204@verizon.net>
In-Reply-To: <4A9F9DEF.5070204@verizon.net>
Subject: Re: [CR] black rims...


Harvey,

The first question would be, when where anodized aluminum rims first commercially available. I think that the first colored rims were "gold anodized".

The black and all other colors are dyes applied to the porous anodized aluminum surface which is then sealed to protect the dyes from deteriorating.

Aluminum anodizing is a layer of aluminum oxide that is electrochemically created on the metal surface. So called clear anodizing is a very thin layer of aluminum oxide which provides a hard protective surface on the soft aluminum. Hard anodizing provides a much thicker layer that can be up to .005" (0.13mm)in thickness. It's usually a dark gray or brown color.

The instant a pure clean aluminum surface is exposed to the atmosphere it starts to corrode forming a layer of relatively inert aluminum oxide. This is what gives aluminum it's corrosion resistance.

Pure aluminum is a soft relatively weak metal. For most commercial uses aluminum is alloyed with small amounts of other metals such as copper, zinc, magnesium, manganese and so on. The alloys increase the strength and hardness.

Aluminum alloys are not as corrosion resistant as pure aluminum so they are frequently anodized for both practical and cosmetic reasons.

I have a pair of black anodized Super Champion Arc-en-Ciel rims so they were available before the Wolber acquisition, when ever that took place.

Chas. Colerich Oakland, CA USA

Harvey Sachs wrote:
> I'm struck that the Austro-Daimler Vent Noir, with its all-black DuraAce
> group, did not come with black-anodized rims. I infer that they were not
> widely available then. When did that fad (if I might use the term)
> begin and when did it get pretty commonly seen? My only clue is after
> the Vent Noir, so after maybe 1980, but by the time of the (off-topic)
> DuraAce ultra-glide, which is sometime mid-80s. I have an orphan sew-up
> of that era with a black D/A hub.
>
> Data, insights, and vague memories of the type I no longer have are all
> welcome - if it was still in Our Era.

>

> harvey sachs

> mcLean va