[Doh! 'Phone rang, I got distracted, and posted this to the wrong thread. Apologies if you get multiple announcements of a new post with the same title...it should have been here from the start]
Hi Jawine!
One of the best resources for bicycle touch-up paint I've found is nail polish (varnish). Now that a wider range of colors is available, I even found a sparkly metallic blue that is a dead-on match for the "Ice-Blue Metallic" color of my 1983/84 Centurion ProTour. Shisedo of Japan (spendy at USD$9/bottle!) came through for me in a match for the "Pearlized Maroon" with micronized gold-flake inclusions of my 1980 Centurion Pro Tour and Urban Decay came up with a superb match for my 1989 Mitaya 1000LT's "Light Metallic Smoke". The nice thing is (in Danneauxville, anyway) you can buy the bottle, take it to the door, shake it well, and hold the clear-glass container against your bike paint and see if it's a match in outdoors lighting. If not, the stores I've found were very willing to do an exchange so long as the bottle remained unopened.
If you go this route, don't forget...many commercial paints are sprayed over an undercoat, and this undercoat can alter the appearance of the final finish. You may need to dab on a spot of light grey or even rust-red (known here as "hot rod primer red") undercoat before touching-up if you are to get a perfect match. You might also wish to coat the final job with a dab of clear nail polish to duplicate the clear coats so often used on commercial wet-paint frames or to match the high gloss of the more recent powdercoats. My blue Cent was a real challenge, because the frame was fully chromed, then painted in five successive stages; it is hard to match that "depth" with a simple dab of color, but I got very, very close using a lot of care.
In 1989 when my Miyata was produced, the US market was in the grip of
Miami Vice, a popular television show about drug interdiction, set in Florida. "Sonny" and "Crockett" suddenly became popular baby names, and we were plagued with pastel palettes of juxtaposed turquoise, teal, and aqua along with orange, pink, and sea-blue. Guys wore unlined white suits over scoop-neck pastel Tees and forgot to wear socks with their loafers. And...bicycles -- including my poor Miyata 1000LT -- were factory-painted to match. The base coat was a lovely metallic "smoke", but the transfers...oh, my. They were white, but interspersed were pink and orange and blue triangles, dashes, and color blocks; the most glaring were large pink triangles in place of the "Y" in Miyata. I used a 5 "0" brush and xylene as a thinner (xylene is the universal solvent for nail varnish) to re-create the lettering I substituted more subdued colors using metallic nail varnish in jewel tones. You can see for yourself in the photo below. I used to scratch-build model cars (even made molds and cast the tires from various forms of synthetic rubber) and hand-lettered them after painting, so the practice came in handy. Sadly, adventure touring on rough roads and too much shop work have made a mess of my fine motor control ("That's handwriting? You're a doctor, right?" is what I often hear now, but won calligraphy awards in high school), but I can still do a decent job on repairing chips and the odd scratch or scuff.
Don't forget, Jawine, clear-coat rubbing compound is your friend. Much of what makes a bicycle paint job look ratty magically disappears once the old wet-paint is cut and leveled, then repolished and waxed properly.
Retouching an old bike is also a golden opportunity to create a head badge if the original was only a transfer. The one you see below is a wood nymph, a play on my family surname. Jawine, you have such great artistic talent, this would be a cinch for you and the results would be spectacular, I know. I made this one from hammered heavy foil over a pre-cast pewter buck. Since I didn't make the original pewter buck, I can't claim full credit, but the foil version worked nicely for my headbadge. The backing is a piece of shaped polycarbonate, which is soft and easily shaped/worked/formed, mounted on industrial-strength 5mil adhensive foam-tape. I put it together one rainy afternoon when I was bored. Years later, I saw a nearly identical piece (the nymph) in stamped and plated steel when I took my sister to a bead-shop...ready to go for the princely sum of USD59¢. I bought several in case mine needed replacement! They must have used the same pewter master to stamp it.
As for rust-stopper, I completely agree with Andy; all can do a decent job, allowing for the individual formula/form ("Follow The Direction" is a good idea). My favorite is Ospho, available here:
http://www.ospho.com/ There's a number of essentially similar products available in the UK and EU that will do the job.
All the best,
Dan. (who knows more about nail varnish than he ever imagined he might...)