jetrock: I used to use an automotive primer made by Plasti-kote called Car Color #632 gray. I did some of my own testing and found that it was unnecessary. The Pollyscale adheres well to brass. The best paint for adhesion is Scale Coat, but it is solvent based which makes it a pain to clean up and the stuff takes about a week to dry even if you put it in the oven.
sumpter250: Thanks Pete, wait 'till you see my next article in RMC. It will be all about painting.
engineshop: I mix the 50/50 solution of alcohol and water and keep it in a bottle. This is the only thing I use for thinner. Just make sure you shake it up prior to using it. Yes, the 50/50 mix of gloss and paint is thinned with it. By mixing the gloss into the paint you get a much better finish. Putting a coat of gloss over flat works, but it is another thickness of material added to the process. I do completely disassemble the drives on steam locos. Mark the inside of each driver with a scribe. I mark them 1, 2, 3 and so on for the insulated wheel. I then mark the frame with a small "I" on the insulated side. I do the same on the tender. This eliminates the guess work when reassembling. You can also mark the inside of each rod. I mark them 1e, 2e, 3e...ect. for the engineer's side and 1f, 2f, 3f...ect. for the fireman's side. The valve gear can be painted all at once and when the paint is dry just move the rods around to loosen them back up. If you run into any problems just give me a shout. I'm sure you will do fine.