My 83 Austro-Daimler has a few spots where the paint has been scraped off, showing rust on the underlying tubes. I totally stripped and painted my other bike, but I really like the color of the A-D, so I'd rather just touch this one up. This is a manganese alloy frame and I've never done any sort of touch up work before. So now for the questions:

1) What are the odds that the rust only exists at the scratched areas?
2) What are the odds that I can find a color even closely resembling the original metal-flecked greenish blue paint?
3) Is there any special prep needed to paint manganese alloy?
4) Any other tips for retouching a bike's paint?

Thanks.

I never worked with manganese alloy which I didn't even know that it could rust! But as far as getting touch up paint, all you have to do is take the bike down to a hobby store and try to find a bottle of Testors or some other brand of paint that closely matches. The only other thing you can do which is expensive, is to take the bike to a auto body paint shop and see if they can match it, but they will probably only sell you nothing less then a quart. I would try to match it as closely as I could with Testors or some othe brand of model paint.

Dupli-color, available at auto parts stores (see Kragen or AutoZone et. al.), has received some favorable reviews on the 'forums. I personally can't attest to their efficacy.

Nail polish. Cheap available-everywhere enamel nail polish. Get the closest glittery (or "metallic looking") greenish-blue you can, apply it carefully being sure not to overdo it, and feather the edges in slowly so it looks good. In short -- match the colour, and above all take your time. If you were seriously hardcore, you could cut some of an aluminum can to tiny tiny bits and mix it in the nail polish to achieve a similar effect.

I found a perfect red to match my winter beater's various nicks and scratches, but after a bit I got lazy and used purple and brown. Meh. :)

There are two kinds of color matching: "Absolutely perfect" and "It might as well be lime green." "Not quite perfect but close enough" does not exist. A less-than-perfect color match will draw your eye to the touched up chip much more so than if it was left bare.

I own some bikes that have fade and shadeshifter paint jobs that simply can't be color matched. I treat the nicks with clear nail polish and have been quite satisfied with the result.

A lot of auto paint stores will match the color by computer and then put it in an aerosol can for about 20 bucks.