I also have had good luck with red oxide primer in dry climates. Regular grey primers will rust in a few months requiring sanding (once again) down to bare metal. You can however get an etching primer that will not rust. They are fairly expensive costing wholesale around $90.00 per gallon. They also require a catalyst to kick off. There are some aerosol versions of etching primers available, Eastwoods has one, but they are extremely expensive at $20.00 a pop! The flat black primers look good but I have had no experiance with them. Doe's anyone know if the black primers hold up to the humidity without rusting?