Painting Plastic Models

I am looking for a painting that can be hand painted in thin layers, but complete, or something that stains of plastic rather than creating a layer on it, such as acrylic.

Do not give up the acrylic craft ... you can dilute to apply thin layers, and you can also mix them with different mediums for different effects. If you really want to avoid acrylic, try coloring Dr. PH Martin ... do not know if they will adhere to a hard surface, smooth plastic.