Courtesy of j.r.hawkins from this thread
The following are general tips you might find helpful for DIY spraypainting bicycle frames.
To get a good clean coverage without the paint spattering or going on three coats at a time you want the paint reasonably thin.
Warming the can in really hot water always worked brilliantly for me with the aerosols. You may need to use oven mits to hold the can. If so, you've got thje temperature about right. (Warning - This is dangerous - please exercise care and take appropriate safety measures.)
â€¢ Do the light colours first.
â€¢ Use the best quality masking tape you can afford, and press down all the edges with your thumbnail immediately prior to spraying.
â€¢ Avoid tight compound curves with the tape
â€¢ On the front where you've got the white on the headtube, it would have been OK to cut thru the tape to get the shape with a semi-sharp hobby knife while on the frame so long as you don't press too hard. The paint would fill any cuts through the primer.
â€¢ I would not do this under any curcumstances on an alloy or CF frame, or elsewhere on the bike. In these cases, run a biro over the tape around the lug line, pull it off gently and put on an artists cutting board, cut it and reapply to the frame.
â€¢ Remove masking tape by peeling back on itself 180 degrees. Lifting at 90 degrees will usually take paint off with it. Mad
â€¢ Minor oversprays can be rubbed away with a typewriter eraser pencil or gently scraped with the edge of a sharp curve-blade hobby knife held at 90deg to the paint.
â€¢ Multiple light coats allwoed to dry in between gives a much better result than a few heavy coats.
â€¢ Finish off with clear.