Hi Guys, thanks for the brainstorming. I tested the technics on plastic toys first. With enamel topcoat (Revell paints) it didnīt work, probably the enamel did not get through the water.
What worked: enamel base coat 1 day drying, hairspray coat 1 day drying, acrylic top coat 3 hours drying and washing with tap water. This works well, nice chips can be done with toothbrush, ear cleaning sticks or needle.