Our primer of choice for this project was PPG's NCP 280. Although it's a mainly a filler primer, PPG's Jeff Griffin says that this product does have corrosion protection properties. It's also a two-component primer, as it gets mixed 2:1 with the NCX 285 hardener. Studio Auto Body likes it because it's thick, requiring only two coats, in this case. According to Studio's Jeremiah Becker, PPG primer is glossy rather than flat, which gives the impression that the car is painted, allowing you to look down the body and check for straightness. "It's better to see wavy primer than wavy paint," he concluded.