Aluminium Frame Damage

limitandbeyond

Good Morning Learned Ones,
I have a Dawes Galaxy Twin (A Tandem), Quite early in its life I fluffed a gear change and unshipped the chain which became jammed against the frame, when I unpicked it, I noticed that I had stripped the paint back down to bare metal. I kept an eye on this, watching for signs of rust, and was beginning to congratulate myself on bike husbandry cos 18 months later, I have no signs of rust. However, after this weekends ride, I was cleaning the bike, when I noticed that the paint around the f'rd bottom bracked was peeling, I rubbed it off to find nice shiny metal, expecting nasty brown rust. Hence the penny dropped and I now know that the frame is aluminium.
My Question: What do I apply to the bare metal, in order to preserve it, can I buy it from my LBS, how do I best maintain the aluminium frame, to prevent more corrosion.
Thanks for any advice.

Steve H

redddraggon

Aluminium will look after itself. It forms it's own impermeable protective oxide coating, preventing only a few microns of oxide forming on the surface.

limitandbeyond

Hi Red Dragon,

Thank you very much for that. It gives me peace of mind. I will keep an eye on it though.

Steve

alfablue

You could fit a Dog Fang which should prevent this happening again.

redvee

A coat of clear laqueur or borrow your stokers clear nail varnish when she ain't looking to cover the bare aluminium and to stop the paint lifting.

vbc

Aluminium will look after itself. It forms it's own impermeable protective oxide coating, preventing only a few microns of oxide forming on the surface.


That's true if the frame is made of pure aluminium but using modern alloys you will need to use some form of pre painting treatment. Unless you can get hold of someone with a machine which will locally restore the anodise, your best bet is to treat the bare metal with Alocrom before repainting.

limitandbeyond

Thank you very much. Its warming to know that people are out there giving their time and knowledge so willingly. I will now be able to fettle my bike and have confidence that it will not deteriorate.

You're all 2 wheeled knights of the road.

Steve

redddraggon

vbc wrote:

That's true if the frame is made of pure aluminium but using modern alloys you will need to use some form of pre painting treatment. Unless you can get hold of someone with a machine which will locally restore the anodise, your best bet is to treat the bare metal with Alocrom before repainting.

I've had large bare bits of 7005 Al alloy on my commuting bike for ages, and it's still shiny, so no treatment is really necessary.