Not sure I agree that corrosion is always progressive. Any such assertion is by no means "too well known to require proof". It is well known by metallurgists and engineers that some metals do form oxides that deposit as hard and realatively uniform coats on the surface of the metal and prevent oxygen from contacting the underlying elemental metal, thus preventing further corrosion. Normally corrosion of metal is due to a combination of oxygen and moisture. So if a bicycle from has rusted from being left outside or in a damp building, but has since been stored in dry conditions, it is not at all certain that failure to remove existing rust actually leads to futher corrosion. That might be the case if the existing oxide acts as a catalyst to further corrosion or if it traps moisture, but I've not seen a study that proves that. I do suspect that iron rust not forming uniform coats as with aluminum and copper oxides, for example, may mean that the iron oxide does little or nothing to protect the underlying metal from oxygen. Certainly, removing rust AND painting or otherwise coating the surface will probably reduce further corrosion, but I'm not at all sure that simply removing rust, without applying paint, will help at all - it might even hurt. Just as an example, I've decided on my currect Schwinn Sports Tourer project, that having touched up all the large scratches, that I won't touch up all the tiny ones, as the inevitably imperfect touchups may detract from the appearance more than leaving a tiny scratch here and there. I did thoroughly wash the frame and got most of the rust out of the scratches. And when rebuilding bikes, I always apply very many coats of premium quality automotve paste wax. In this case, I'm counting on the wax protecting the tiny scratches, but if it doesn't, I might have been better off leaviing the surface rust in the tiny scratches rather than cleaning it off and exposing the metal beneath to air.
Regards,
Jerry Moos Big Spring, Texas, USA
gholl@optonline.net wrote:
Alex:
I'm replying to you again only since you are a prominent dealer and yo
ur statements may influence some collectors. I myself hold you in este
em and, as you know, in the past, have even tried to buy a cycle
from you.
That having been said, no dealers' or collectors' statements can b
e spared criticism no matter whether they or their bikes are admired.
Rust and corrosion are damage and sooner or later will destroy a cycle.
An honest dealer (a dealer must be held to a higher standard than a col
lector) must never represent them as "patina". I would never buy a
bike from a dealer who made such representations.
Rust and corrosion are never "passive" but are always progressive.
Their progression varies depending on certain conditions. This is to
o well known to require proof.
The patina present on museum sculpture is protective and, when damage
d, is repaired.
As far as repairs to a vintage cycle, they must be done correctly with
respect for the original finish and design. That is the key issue con
fronting the vintage bicycle hobby.
Since so few older vintage bikes are now available, let alone in good
condition, I do not think you are correct in assuming that more bikes
have been destroyed by attempts at repair than by neglect. Of course,
no one would condone poorly done repairs.
Regards,
George
George Hollenberg MD
CT, USA
Date: Thursday, July 17, 2008 10:18 am
Subject: [CR]Conservation/restoration etc
To: Classicrendezvous@bikelist.org
> Obviously you shouldn't leave any "patina" on a bike that is
> actively damag
> ing to it's condition.
>
> Of the four bikes I sent photos of the Bastide was the "limit"
> case and the
> one I was expecting this sort of criticism about.
>
> It appears to me that the corrosion on the Bastide is passive,
> not active,
> and that it will stabilise in this condition if the bike is
> conserved in a
> dry atmosphere. But if someone can prove this is scientifically
> incorrect,
> then I will agree the bike should be cleaned polished and waxed.
> NOT restor
> ed under any circumstance. On the other hand, the bike has been
> here a numb
> er of years, and the condition hasn't changed one bit.
>
> In museums, I haven't noticed that bronze Greek statues are
> polished up to
> a high finish, and the green surface oxydation removed to get
> back to the o
> riginal colour? I understand that the patina is actually a
> surface protect
> ion against the ravages of time.
>
> But of course all of these museum curators might just be idiots,
> or not hav
> e enough skill, money, or talent to restore/have their works of
> art restore
> d properly?
>
> Anyway my point was : far more damage has been done to bicycles
> by the "il
> faut que ça brille" ("let's get this nice and shiny") brig
ade
> than by the
> conservationists.
>
> In actual fact I think that at the next Cirque there should be
> an "over-res
> tored" category. Winners should be made to hand over any bike
> they have not
> already destroyed, and banned from buying any more bikes until
> they have a
> mended their ways.
>
> Alexander March
> Bordeaux
> France
>
> =0A=0A=0A
> _______________________
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>
George Hollenberg MD
CT, USA