shot blasted aluminium finish?

[Robbo]

I'm wondering if i have an ali frame shot blasted would it leave an even finish? And could i just leave it naked?

[mrcharly-YHT]

I would have thought it was a bit soft for shot blasting.

Some sort of anodized finish would be better than raw aluminium. Raw stuff would corrode.

[gibbo]

I'm about to blast and anodise my ali framed bike. I've had a word with a company who will do the anodising for me and mentioned about pre-blasting for the even finish and they said they'd advise me since it gets dipped in an acid solution which removes the ali and creates an even finish (to a point). Whilst ali is considered soft, say compared to steel, it can be blasted. It depends on the media used and how long you hover over a particular point.
Gibbo.

[chrisbainbridge]

Raw stuff would corrode

You are quite right raw aluminium corrodes.  The time for corrosion to appear in the presence of Oxygen is in terms of milliseconds as Aluminium is incredibly reactive.  Fortunately the one atom thick layer of aluminium oxide that appears is incredibly inert and protects the rest of the aluminium.

[woollypigs]

I don't know how they sealed, to stop corrosion, the gun metal look on my aluminium Principia. But it looked well cool, felt great but now it is dirty. I have yet to find any cleaning chemical/product that can restore it to its former glory.

[jsabine]

Raw stuff would corrode

You are quite right raw aluminium corrodes.  The time for corrosion to appear in the presence of Oxygen is in terms of milliseconds as Aluminium is incredibly reactive.  Fortunately the one atom thick layer of aluminium oxide that appears is incredibly inert and protects the rest of the aluminium.

If that one atom thick layer protects the rest (as it ought to from what I remember of my school chemistry lessons), how does the white bloom of corrosion grow? It seems very ready to appear on items that are exposed to WEATHER.

[mrcharly-YHT]

It's not the weather that does it, it is the dirt.

Raw aluminium only forms the protective layer when clean and in the presence of abundant oxygen. Get it wet, dirty and it corrodes, producing the  well known white bloom.

[Riggers]

In the words of Eugene Levy in Best in Show, "I never knew that!"