Good afternoon, I painted an iron lattice with water-polish, I gave the first hand a brush, but I didn't like the hardness of the paint. I decided to change it for one of sinteplast 3 in one, converter, antioxide and synthetic enamel when you wait for it to repaint. Most of the places I consulted say that the paint below will crack because it is water, that it cannot be painted with synthetic paint on top of a water paint. When in doubt, I came painting a part with a synthetic when you wait to see what happened, and nothing happened, it did not crack or lift. I have also tired of painting sockets with satinol that were previously painted with latex and nothing ever happened. My experience as a painter is only hobby, for my home, so I consult since I am not professional, and to listen to their opinions since apparently what they tell me does not happen, and iron lattices give enough work to paint them by brush and I don't want to have future problems. Thank you and I await your advice and opinions.