Re: [Classicrendezvous] Re: Frame tubing & chrome


Example: Framebuilders:Brian Baylis

Date: Wed, 18 Oct 2000 17:51:12 +0100
Subject: Re: [Classicrendezvous] Re: Frame tubing & chrome
From: "Hilary Stone" <Hilary.Stone@Tesco.net>
To: Jerry Moos <moos@penn.com>
CC: classicrendezvous@bikelist.org


No chrome is normally only applied to the immediate area and a little of the surrounding area, the rest is masked. Chrome plating is not good for several reasons. Firstly the tubes have to be highly polished first and this removes metal. And secondly the frame is dumped in all sorts of pretty nasty acids and if these are not carefully washed out after the plating is finished can cause severe corrosion from inside. The whole frame is practically always dunked in the baths. And thirdly the plating causes a change in the steel alloy at the interface between it and the plating which leads to hydrogen enbrittlement. This makes far more likely tube failure. Reynolds forbid chroming on 753 and Columbus for many years recommended that is should not be used on their tubes. It's pretty but it won't increase the life of your frame. And no Colnago or any of the Italian builders who use chrome have not found any special ways just to chrome the lugs ­ they just take the risk and hope that frame has moved onto a new owner before it fails. I've not seen stainless steel lugs in the UK though several builders use stainless steel dropouts ­ Donohue and Argos for two. But stainless can have its own problems if the stainless is not chosen carefully. Some stainless alloys are very brittle and that is not a quality you want in a dropout. Hilary Stone.

----------
Jerry Moos wrote:

>


> Very educational, Hilary, I didn't realize that the current 753 is thicker
than the

> original stuff. Makes one feel a bit better about this tubeset, as most of
the

> horror stories surrond the early 753 frames. This suggests to me a related
subject

> - that of chrome. Is it safe to say that framebuilders have real concerns
about

> chroming tubes 0.5 or thinner? Even though most frames use chrome only on

> lugs/forks/stays, it is my understanding that one usually chromes the entire
frame,

> then polishes only the exposed chrome, while the unpolished parts are painted

> over. Are walls of forks and stays sufficiently thicker, at least at the
bottom,

> that chroming or half chroming forks and stays is safer (presuming this much
might

> be done without chroming the main tubes)? I presume that stainless steel lugs

> might give a similar appearance while avoiding the need to chrome the much
thinner

> tubes, but don't stainless lugs discolor during brazing, requiring polishing

> afterwards? I also note that several of the remaining Italian steel frames,

> including Colnago, feature chromed lugs despite using thin walled Columbus

> tubesets. Have they devised a way to chrome the lugs without chroming the
unbutted

> portion of the main tubes, or are they simply compromising durability for

> cosmetics? I realize these questions betray a general ignorance of chroming,
but

> the only cure for ignorance is to ask.