Bicycle Mechanics - Scratch treatment on fine, alloy C&V components

Scratches on nice C&V components. Sigh.

I pretty much hang out in the C&V section. When something comes up that’s a bit too ... well, specific, then I come here.

I have a vintage piece that, if perfect, would be worth gold. But, it isn’t and it ain’t.

Besides just cleaning, bit of rubbing and declaring them battle scars, are there specific home-brew options for making this 1st generation C-Record RD look better?

http://i120.photobucket.com/albums/o191/LeicaLad/IMG_0007s.jpg

If these were MY battle scars, I’d wear them proudly. Unfortunately, this came off a 1985 (531 anniversary decals) Mercian. I am the second owner. It was originally purchased fully dressed in 1st Gen C-Record (not Delta brakes, tho).

But the first owner abused it, caring little for its condition. It was a long-distance CL buy, and I was/am a bit too trusting. Some real issues were hidden, and the seller proved a right jerk. A bonafide lounge lizard. There’s a kink in the drive chain stay. The axle lines up fine, but the derailleur angle is off.

I can comment that this classic RD shifts like an utter POS. I don’t think I’ve ever had such poor performance. BUT, it is most likely a problem from the kink, which is quite nearby, rather than the fault of this RD. I’ve disassembled the RD, and it doesn’t appear to be bent. I actually do have another of these derailleurs in the treasure trove, but my eye-ball comparison is inconclusive.

Anyway, pretty much every component on this bike, including the saddle, is scratched up.

I leave aside, for now, the question about the kink in the drive side chain stay.

SO, the question here is what, at best, can I do about these scratches – besides ignore and use? A little Mothers Mag & Alum polish, Scratch-X, what else?

Thanks.

My restoration experience is with automobiles but I think the same techniques will work for you. I would glue 600 wet or dry sandpaper on a tongue depressor and wet sand the surface. Using the tongue depressor as backing will keep you from rounding the edges, particularly the logo. It does not look to me like you will be able to remove the deep scratches without loosing some of the logo; you'll have to decide just how deep you want to sand. Then I would graduate to 1200 grit wet or dry glued to a tongue depressor. It looks like the piece had a satin finish and the 1200 will give a similar appearance. If you want a chrome plated look, graduate to 1500 grit, then rubbing compound and finally a polish like Mequiar's #7. Go slowly, be patient.

The problem with scratch removal on almost all aluminum components is that they're anodized. Any effort to polish down to the level of the scratch means samding or polishing off the anodized layer.

There are three problems with doing that.

1- the base metal is usually a bit darker, more the color of steel, than the silvery color of the anodizing.
2- bare aluminum is vulnerable to corrosion. Over time, it forms a self protective oxide layer, which is a bit whiter than the base metal (like when it's anodized), but the presence of salt, water, or any corrosive agent can disrupt this process causing pitting and attacking the structure of the component.
3- It's almost impossible to maintain a decent finish on non-anodized aluminum, so removing the anodizing is a poor choice for collectors.

I suggest you leave it alone, clean it as well as possible. Use a wax and see if it camouflages the scratches at all. If the scratches are darker there is a chemical process that lightens them and you can try before sealing it with wax.

Thanks, guys. I'll take the less aggressive route. A bit more cleaning, light hand polish, then wax. Guess it'll become a "conversation piece" on a rider. . . presuming it isn't actually bent.

I'll need to put in onto another bike to test her out.

:D
Cheers.

Isn't it possible to fully disassemble Campy derailleurs?

If so, then you could have the parts re-anodised... or try it yourself for some mad home-brew props.

IIRC, caustic soda is the go for removing the old anodising before polishing.