The cold galvanizing paints from the hardware store have the same zinc content as Pettit 1792. I have used several flavors including Rustoleum and call it "qualified success". The blades stay clean with some growth on the hub. I sand the prop with 220 nice and clean then wipe with acetone. Two coats seems to hold up all season.
Pettit 1792
http://www.pettitpaint.com/product.asp?id=262