One aspect of the present invention is a coating system for use in a wet on wet coating application process. The coating system includes a first coating composition, a second coating composition, and a boundary layer. The first coating composition includes a first bulk polymer resin and a first reactive component selected from the group consisting of a part A and a part B reactive component. The second coating composition includes a second bulk polymer resin and a second reactive component comprised of the other reactive component of the part A and the part B reactive component group. The boundary is formed upon applying a first layer of the first coating composition to a second layer of the second coating composition. The boundary layer includes the reaction product of the part A and the part B reactive component and is situated between the first layer and the second layer.