Can Rust Bullet be applied over existing paint?

When you have an existing coating that exhibits poor adhesion and is flaking off any coating applied over that coating is subject to the same behavior. As this coating continues to lose its bond with the substrate, the Rust Bullet or any coating on top would pull up with it or bubble. You can scuff up the surface and apply several coats of Rust Bullet, and extend the life. Although it will provide protection and longevity, it will not have the optimum performance of an application over a surface that does not have an existing coating failure. To achieve maximum adhesion and performance, it is always recommended to remove any old paint or coating before applying Rust Bullet.