I realize your not wanting to got really spendy, but what is your $ range?
Tom, I use a sandable grey primer that soaks into the wood and seals it. It takes three days with one coat every day until it stops soaking in and starts to form a layer on the blade surface. I got your blades done and they need two more coats of this oil-based primer yet:
I spray my blades with either DuPont Imron or PPG Shop Line acrylic urethane. Either one is about $150/quart in Olympic White (PPG part #924260), and takes specialized equipment for application. It is a two-part base coat/clear coat paint. The blades will be sealed when you get them (except for the bolt holes you have to drill and silicon sealant works good there). They can be painted with any good quality acrylic enamel or urethane, and I would use automotive paint, not hardware store paint. You're not going to find hardware store paint with hardener in it, nor is the paint you get out of spray cans designed to be flexible or stand up to abrasives like good quality automotive paint. Most canned spray paint is alkyde enamel and it's soft and chips or peels easily.
I've gone away from Imron, for the most part, because it's highly toxic and requires a contained air supply respirator during application to prevent breathing the vapor. The PPG Shop Line paints are a lot easier to work with and you can apply coats within an hour of one another, wet sand the base coat the next day with 1200 grit and apply the clear coat.