[- seb]

I know that aluminium oxide forms a non-porous protective layer, as opposed to iron oxide 9rust) which is porous and as such spreads throughout the metal.

So in theory it should be no problem to have a bike frame that is bare aluminium. Unpolished, unanodised, unpainted, as raw and as dull as they come.

What's it like in practice? Any reason why I NEED to get it clearcoated/anodised etc.

- seb

 

[Serial Midget]

The sweat from your body will corrode the surface of your top tube rather quickly. So if you ride hard enough to drip... I see it on tri-bikes all the time.

 

[LostBoyScout]

I rode my old Zebdi as bare aluminum (sand blasted finish) for about 4 months with zero effect. I'm not sure about long term, but it would take a WHILE

 

[Tenchiro]

You can always put a matte clear coat on it for protection.

 

[EBasil]

It depends which alloy your frame is. If it's 6061 aluminum, you can polish it up and it will get dull over time but not really corrode or smut your legs if you brush up against it. It would still be better to have uncolored anodizing or clear coat over it, of course.

If your frame is 7000-series aluminum, it should be anodized or clearcoated, as it's far less resistant to corrosion and will noticeably react to acidity of your persperation or any water in the State of New Jersey. These alloys will grey-up quickly, leave black marks where you rub against it and can be structurally compromised if you leave it in the elements or sweat on it a lot.
Easton tubes are 7000 series, and are all either anodized or clear coated. If you leave these tubes bare and unrpotected, you should polish them regularly to combat corrosion.

 

[- seb]

It's 6061, so I guess that's something.

Here's a pic:

I might get some spray on clear coat, hassle

 

[Serial Midget]

Cool! What's the rest of the frame look like? I don't think there is much chance of body sweat doing any harm to this. DH bikes are meant for thrashing not looking good...

 

[- seb]

More info: http://www.ridemonkey.com/forums/showthread.php?s=&threadid=34907

 

[RunIsland Rider]

Seb,where do you buy your orange frame please ??? In europe ??And the price ?

 

[- seb]

I bought mine at Mountain Trax in england. G to www.orangebikes.co.uk for a full list of dealers, any will do. Mine was £1500, a non-floating-brake one is £1300.

Go to www.xe.com/ucc to convert that into your currency.

 

[RunIsland Rider]

Thanks.

 

[Spud]

My first thought is that Seb has it correct. Was reading up on aluminum culverts and oxidation last week. We specify and install aluminum culverts in pH environments ranging from 5 to 8. The oxidation is reportedly desireable because it forms a protective surface....

But, an aluminum pipe in the ground is more of a static environent than a bike frame flexing and rubbing... Plus Serial Midget's observations can't be discounted....

interesting.... hmmm...

 

[CreeP]

hey how'd you tkae the paint off? i'm thinking of repainting my alu bike.