Picked up some additional rust-protection from PM Industries, the guys who make Master Series coatings. I had already bought some MasterCoat Silver rust sealer/primer, but it’s silver, and I want the chassis to be painted black. So I ordered some of their MasterSeries AG111 (aka, TractorKote). They have a MasterCoat Black, but I believe it’s not UV-stable. The AG111 is. It’s a two-part moisture-cured urethane and I think it will be all the protection I need when painted over the MasterCoat Silver.
This can be sprayed, or brushed with good results. I’m not ready to hook up the paint spray guns yet, so brushing it will be.