Greetings. If you expect the parts to be painted to reach a high temperature, I would use one of the exhaust manifold primers and paints. Today, there are lots of colors in redi-mix spray cans. If you want a special color, look at the following note I posted to a forum in the MyLargeScale site. The procedure I followed to repaint a badly scratched Aster Jumbo boiler. For the special color, the cost was about $80 [50 Pounds]. You need either a respirator or a warm temperature for the automotive paints.
"Greetings. Painting a boiler jacket from scratch can be easy, but it is also a little expensive. At the suggestion of Bob Weltyk of Weltyk's Whistles, I took a new, but badly scratched boiler jacket for an Aster Jumbo to a local auto paint supply store. They did a spectrum analysis of the original jacket and mixed their minimum batch of 16 oz. and put it into spray cans with special nozzles. Of course you have to wet sand and properly clean the jacket before painting. On recommendation from the paint store, I used 600 grit wet sandpaper, then washed it with soap and water and finally washed it down with alcohol. Before painting, I used a hair blower to make sure the jacket was completely dry. Because of the makeup of the paint, you must have a very well ventilated area and the temp should be 70 degrees. I applied 4 thin coats at about 15 minute intervals and then baked the painted jacket. Instructions say to bake it in a preheated oven at 140 degrees for 40 minutes. Our oven will only go down to 180, so I gambled with the higher temperature and it worked well. Also, per Bob's recommendation I left the jacket in the oven after turning it off to let it cool gently. The paint supply guys said properly applied paint will withstand 600 degrees without difficulty. When the jacket cooled, I compared it to the factory painted steam dome cover. The color of the newly painted jacket was indistinguishable from the factory paint job, regardless of the light [direct sun, flourescent, haolgen, incandescent or just a bright room]! Because of the minimum order, I now have enough paint for 7 more boiler jackets, tender shells or even coaches. The cost for the spectrum analysis, paint and spray cans was $72 plus tax. Would I do it again? Absolutely, even though the paint is expensive, the value of a properly painted vs. badly scratched locomotive more than makes up for the cost. Good luck."
Regards,
Will
