You may have noticed that on some bicycles, the edges of the lugs are attractively outlined in gold or in a contrasting colour. This treatment is called "pinstriping" and is done by hand after the bicycle's frame is painted. I like the look very much and decided to try it on my Raleigh Lady's Sport, in preparation for a more serious project. I was nervous, but it turned out to be easier than I expected. If you want to give it a try yourself, here is how:
To go the truly professional route, you will need enamel paint and a pinstriping brush in the smallest size available. Having said that, I do not think these tools are necessary unless you are an experienced professional and are pinstriping a $3,000 frame with super-intricate lugwork. The enamel method can be difficult and messy, plus enamel paint contains led. Instead, I recommend a paint pen. Even professionals use these for simple projects. Several manufacturers make quality paint pens that are suitable for pinstriping bicycle frames, including Sharpie and DecoColor. Make sure the paint pen is oil-based. The label should explicitly state that it will leave permanent marks on metal surfaces. The size should be "extra fine". The price is usually in the $2.00 - $4.00 USD range.
The paint pen needs to be started by pressing down on the nib and pumping it several times - something best done on a piece of paper. When the paint flows through the pen slowly and evenly, you can begin.
Before starting the process, it is a good idea to clean the edges around the lugs and wipe them dry. Otherwise, your paint pen may get clogged with dust and grime. Once the area is prepared, simply begin to trace around the lugs with the paint pen, at a slow and even pace.
If the pen skips over a spot, go back and carefully re-trace that spot. If your hand shakes and you make an uneven line, or if the paint smears, wipe it off quickly with your fingertip or fingernail before it dries.
Once the paint dries, the marks you have made will be water resistant. If you notice a mistake after that happens, you can still get rid of it by carefully scraping the paint marks off with an exacto knife or a razor blade.
One issue you might encounter with rougher lugwork, is jagged edges. The lugs on my Raleigh Lady's Sports are quite crudely finished, and as you can see above, it can be difficult to make smooth outlines when the edge itself is crooked. But don't worry about that too much; these little details aren't noticeable unless you really examine the lugs up close. And I can assure you that the pinstriping on standard production vintage bikes is just as messy: Whoever outlined the lugs on my Motobecane at the factory did a sloppier job than my DIY.
So really, don't be afraid to go for it. If you have an old bicycle you'd like to spruce up, pick up a paint pen and give it some nice lug accents.