A: There are a host of Rust-Oleum products suitable for exterior work, including Stops Rust, Porch and Floor coating, Professional, and my favorite, Universal, which comes in both regular and metallic colors and does not require a primer. As for using craft paint, you would be wise to build the entire finish using only exterior coatings, as the finish will only be as strong as the weakest link, not the last coat. Thus, you can not create a durable exterior finish with a combination of interior paint, which most craft paint is, topped with exterior polyurethane. On the other hand, if you find exterior craft paint, you can indeed top it with clear exterior spar urethane. Bear in mind that will mean starting with primer, then paint, then clear polyurethane. Personally, I would prefer using just Universal instead of having to buy and use three different materials to get the same results, but it’s your call.