Hi there-newbie to model cars. I bought a 1970 Ford Mustang. It shows yellow with a black interior. When I painted the headliner black, I could see it through the exterior roof yellow. I removed the black. I primed the headliner with yellow. I tried a brush of black last night, and had to remove it-I can still see it. How to solve this? I was using black enamel for the headliner.