Mixing
Hi
There are 2 types of paints, acrylic and solvent based paints. Acrylic (water) based paints will not harm any of the paints. The solvent based paints, Spazstix for example will "eat thru" water based paints. To prevent that from happening you must spray the solvent paint in VERY thin coats. Use a hair dryer to "flash" (dry) the paint. The longer it stays wet the more time it has to react to the acrylic paint. You can apply the water bases paints over any type of paint and it will not harm it.
hope this helps
Caci623