Hand paint it. Use acrylic paints and put the lightest color on first as the base coat. Spray it on if you can. Hand paint the other colors working toward the darkest.
For spraying, you could use an exacto knife to cut out templates for all the colors.
It is important that you use cheaper artist's acrylic paints like the Jo Sanjo brand. These are basically tempera colors with a little acrylic emulsion added to provide better stickum. They thin easily and brush out evenly.
Working with the better grade artist's acrylic paints in tubes is a PITA. You have to stir, stir, stir, and stir some more to get a brushable even coat.
An alternative to this would be to buy better grade tempera paint that has finer ground pigments and add some Future to provide the stickum and smooth flowing.
If you're near an art supply store, buy one tube and try it out.
First of all, the paint I mentioned is Jo Sonja, not Sanjo.
After my post I got to thinking and I decided to do some tests. Despite all the experience I've had with all kinds of materials doing my own art work and in my 33 years teaching art, my hobby modeling has been with balsa. Maybe, I thought, I might be jumping the gun about plastic models.
I did the tests on at least a dozen kinds of plastic and found that for best results using the cheaper acrylic, it should be sprayed on and it is best to spray it over Future. Whether it provides a real economic advantage or not is up to you to decide because I don't know what you're paying for paints.
The good news is that when you play around testing materials, something good always comes out of it. I found out that Future make a good base coat for painting on hard smooth surfaces. This is an asset for me in my radio hobby.
Take a look at this radio cabinet. It is a 1937 Philco that was covered with the notorious "photofinish" which was a photo print that over the years rots and takes the lacquer finish with it. I have filled in these areas on one side prior to painting. I will cover these areas with Future, start the painting with acrylic paints and do the final colors and details with oil paint.
formatting link
I'm doing one side only and will get a scan of this and then a reverse scan. I'll butt them together and my radio will have a new photo print on it. Best of all, I'll make the image available free to all the radio groups.
Here are before and after photos of my work in this area . It is all hand painting and I am pretty good at this. That isn't bragging because I am like every one of you. I can take a couple minutes telling you what I'm good at and a couple hours telling you what I'm not good at.
PolyTech Forum website is not affiliated with any of the manufacturers or service providers discussed here.
All logos and trade names are the property of their respective owners.