Electrostatic coating

In electrostatic painting you need to ground your componet to be painted and then charge your paint. In automotive application we charge the paint to about 80KV,DC.

DC is the only way to go based on the high voltage required to get a good charge.

The problem you will have is that glass normally is not conductive. So you will get a poor transfer. Assuming you are spraying the plastic.

You also need to think about the potential for fire in any electrostacic painting. For every 10KV you need to stay at least 1" away from your ground or you will draw an arc and ignite your paint. Trust me this will happen so you need some way to detect fire and shut down the air and paint.