Acrylic over oil based paints -

One of the first things I learned in art class was - Don't.   However, When I was building models of WWI aircraft, which I usually painted in acrylics, I broke that rule occasionally. The popular varnish among modellers was Johnsons' Kleer. Never gave it a thought even put it over some wood grain effect that had been done with oils. Nothing bad happened and some of those models are now quite old. I think part of it is that the enamels were often applied with an airbrush, so the coat was very thin and dried quickly, or maybe I was very lucky. Being at the stage of bow finishing a model of a modern jet, an not really wanting to spray solvents more than I have to, I wondered. So...I made up a few test pieces. The spare drop tank was airbrushed and the two other bits were brush painted. They all received a brushed on coat of either Winsor Newton Galleria Gloss or Matt. The Matt is pretty flat, the gloss more satin, though another coat would probably go glossy.

This is my experience, and I'm not trying to start the argument all over, just thought I'd share the experiment. I think the results may have something to do with the formulation of Galeria varnish, dunno