At 12:05 PM -0800 11/13/09, neithernors wrote:
>On the other end of experience, I have seen restored, re-painted,
>shiny frames, stored indoors and always kept dry, begin to rust
>again under the paint.
That is a paint prep problem. Obviously, even the paint didn't stop
the rust. I have seen this on brand-new frames, usually partially
chrome-plated ones, where the acids from the chroming weren't
completely removed before painting.
>Wax may help to slow rust but I doubt that it will stop it
>completely. There is no such thing as a perfect seal. From my
>experience with cars, motorcycles and bicycles, the only way to
>eradicate rust is to be sure it is completely removed before
>re-painting.
Nothing stops rust - otherwise, you could paint your bike, and then leave it outside for 50 years in Seattle rain, and it would not be rusty.
How quickly the rust advances depends on how the bikes are stored. If they are indoors, in a relatively dry spot, rust does not form quickly. I had a bare frame, sandblasted, but not coated, in my basement for 4 or 5 years, and no visible rust formed. I don't recommend this, but it's not that big a deal.
You often find NOS tubesets that are 50 years old, and covered only in a bit of protective oil, and they haven't rusted away.
If rust were such a problem, bicycles all would rust from the inside, as the metal is completely unprotected there. Yes, frames can rust through, but the fact that 100+ year old frames survive in good condition shows that rust on bicycles needn't be a huge problem. (Peter Weigle's framesaver will add peace of mind, and I put it in all my bikes, but few of them were treated when new.)
Basically, from my experience, removing loose surface rust and then waxing (and storing the bike dry) will slow the rust to a rate that is close to 0. Maybe the bike will last only 500 years that way... Note that rust doesn't vaporize metal - if there is significant rust, you'll see it as loose flakes forming. (Rust on the inside is more insiduous, as it flakes on the inside, where you don't see it.)
Cars are different - there are lots of cavities, contact points where capillary action will introduce water, etc. The insides used to be bare metal, and so cars rust from the inside, and by the time you see it on the surface, lifting paint, all the metal underneath is gone. Compared to that, a stone chip with surface rust forming is pretty harmless... Also, drying off the insides of a car body is close to impossible, but wiping a bike dry doesn't take long.
Jan Heine
Editor
Bicycle Quarterly
2116 Western Ave.
Seattle WA 98121
http://www.vintagebicyclepress.com