Here is my problem/question...after I apply decals...I add another coat of MM gloss varnish. I want to apply a wash using oil paints but the thinner/wash will attack the gloss and the paint. What would I have to apply to prevent this? Would I have to use an acrylic wash? or apply an acrylic finish? ANy thoughts would be helpful...

Sean

Yes, use an acrylic coat (future) before you do your wash.

I always try to use acrylic washes over enamel paints and vice versa. That way I know I won't have a problem with the wash eating the underlying coats. I also use Future prior to and after applying decals and before washing.

I had painted an enamel then coated it with Clear laquer when dry. Then i did an oil wash, and the enamel paint was wearinf off!! What gives?

I have used oils over enamels and acrylics, with and without a barrier without a problem.
If your going to slather a large amount of solvent over a model, you risk breaking the surface of the previously applied paint, even if it's reasonalbly wel;l cured. . Consider using your wash JUST where you want accents and shadows. DON"T scrub it on. DON'T put so much you have to wipe excess off. Take a small amount of wash and place it where you want it and let capillary action do its thing. Also, make sure, absolutely sure, the base colors are fully, completely cured before you do a wash. This may take a couple days or more for flats. Gloss enamels are going to take a lot longer. If you want to tone down/blend your colors, consider misting the whol;e vehicle with a thin, lightly applied coat of a base color with your airbrush.