polishing aluminium Components

[dvines]

cananyone recommend the best way to polish tarnished or scratched ally components.....

Whenever I've tried it I never seem to get the mirror finish I sometimes see on other preoples stuff....

Is there a special technique/abrasive/polish to use ??

Does the technique differ if the component is anodised /

I have a campag victory chainset which has lots of scratches down the cranks - how do I get them out ?? Brasso doesn't seem to touch it... I am assuming that is anodised ?

[reohn2]

Solvol Autosol from car parts shops,when I was motorcycling it was the polish for a mirrorlike finish on crome and alloy,I still use it on cranks occasionally

[Mick F]

I am assuming that is anodised ?

Generally, yes it is.

Chainsets tend to be, though other Campag components like seatpins probably aren't.

[dvines]

OK

so I how do I restore the finish on the cranks if they are anodised.......

polish the anodinsing off - or is that impossible or a no-no ??

or is there some other way to do this ?

[Mick F]

Paint stripper would get the old coating off, but the result may be quite dull. You'll have to use Brasso or Solvol Autosol to polish them. The polishing will have to be done regularly to keep up the shine.

Maybe some spray lacquer could be used after polishing.

I'm just grasping at straws here, not speaking from experience.

[mw3230]

I watch the Antiques Roadshow and see the experts drooling over antiques displaying the bumps, marks and scratches that indicate much use - indeed reproduction furniture has artificial wear 'applied' to it. Perhaps your components should be viewed in the same way - more valuable because of the very good service provided with much more yet to come!

The mirror finish you see on other bikes may well indicate a fair weather cyclist who is happier sitting on the garage floor polishing and cleaning, than being out on the road getting the miles in.

You may guess I'm not the greatest fan of obsessive polishing!

[steady eddy]

To get a really good finish you will have to use a polishing wheel - you will struggle to get rid of scratches by hand and then to keep the shine you will have to lacquer the component or at least wax polish it regularly. Un-treated Aluminium oxidises immediately on contact with air and goes dull quite quickly.

[gilesjuk]

Un-treated Aluminium oxidises immediately on contact with air and goes dull quite quickly.

I think that depends on the alloy.

I have some truvativ cranks that were painted and that rubbed off in places in use, so I removed all the other paint with some fine sandpaper. I've not polished or lacquered them and they're not what I would call dull.

[gbnz]

The mirror finish you see on other bikes may well indicate a fair weather cyclist who is happier sitting on the garage floor polishing and cleaning, than being out on the road getting the miles in.
!

I made this point to the neighbour, on his commenting on my bikes in their "unmaintained state" being grimy, whilst his was in shining new condition.

His road bike has apparently done nearly 230 miles, though he has to drive it to the leisure centre to ride it, as the leisure centre is nearly 2.5 miles away from home. On a road. And thus not accessible by bike, though he has considered doing this journey

Given my new bike of the same age has done in excess of 20000 miles and the three combined somewhere in the region of 50000-65000 in the last eight years, I struggle to understand his incomprehension of the effect of mileage on wear rates. I don't maintain my bikes weekly for fun, but simply due to a high mileage (Including polishing with autosol)

[simonineaston]

back in the days when I aspired to various motorbikes, in various states of "customisation" (i.e. depending on how far we had got around to ruining the carefully carried out efforts of the original manufacturer...), one of the less destructive things we did was polish the alloy components, It's a very tedious and long process, and at the end of the day, depends entirely on the quality of the alloy for it's success - some alloys, mainly originating from Japan (I'm talking about the 70s) just weren't worth bothering with, which is why they were coated with a heavy, plastic-based, laquer in the first place. Aluminium alloys oxidise quickly, hence coatings like anodising and using laquers, but if you must...
Here's what we used to do: the process is simple really. Start with the lightest cut necessary to remove the heaviest scratches - this may be a light file, or a medium grit emery cloth, depending on the state of the component. After removing the heaviest marks, move to the next lightest grit; repeat. Move to the next lightest grit; repeat. Move to the next lightest grit; repeat... you get the picture. Finish with cloth and Solvol Autosol. The above used to get done, hour after hour, while watching telly. The above is much faster if you have a polishing wheel, in fact now I'm older & wiser, I'd go so far as to say, the above is only sensible if you have a polishing wheel!

[reohn2]

Paint stripper would get the old coating off, but the result may be quite dull. You'll have to use Brasso or Solvol Autosol to polish them. The polishing will have to be done regularly to keep up the shine.

Maybe some spray lacquer could be used after polishing.

I'm just grasping at straws here, not speaking from experience.

I think you're spot on there Mick that would do the job,I have some 105 cranks that I did exactly that with when they had a salt attack some years ago they now look like this:-

[Russell160]

I asked a similar question on the retro bike forum and got this link which I found really helpful. The chap obviously knows what he's doing. It also links to another link (Caswell Guide to Polishing) which is also very helpful and expert.

Basically, you need a wheel. But my local hardware shop also suggested using a normal hand drill fixed in a vice or Workmate or similar and start off using mini wheels in the drill bit, just to get started. But he recommended a drill that's at least 750 w. Worth a try before lobbing out £70 odd on a polishing wheel.

http://www.raydobbins.com/polishing/

[steady eddy]

Badly corroded components can be resurected with bead blasting which is not destructive in the same way as grit. For polishing smaller components a cheap flexidrive with smaller polishing mops operated from a drill which is securely clamped in a stand or a vice will get good results. Autosol is excellent but quite abrasive. You will find various polishing aids in the excellent Axminster catalogue or on their web site.

[CJ]

If they are anodised, abrasion (i.e. emery cloth or whatever) is the only way to go, since anodising is not paint and will not yield to any solvent. You'll have to abrade the anodised surface layer entirely away in order to reach the same level as the scratches and obtain a uniform appearance. That will be a lot of work.

And once you've polished the cranks, you'll have to keep on polishing, very often, especially in winter, or else they will soon revert to an even worse appearance than they have now.

Although they may look a bit bad in their present state, I'd leave them alone, since the paint or anodising provides protection from salt corrosion to most of the surface at least.

[kevincairns2008]

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