Today I applied the final coat of paint to the front brake calipers. They should be ready to bolt onto the car once I install the crossover tubes and new cylinders.
I bought a gallon of a product called RustAway from Halon Marketing in Pennsylvania for $27.95. It is a chemical rust remover that is pretty safe to the environment. I figured I would try this out on the cast iron calipers as an alternative to sending them out for sandblasting. There was some surface rust on the calipers when I pulled them off the car.
I poured enough RustAway into a plastic bucket to cover one caliper and all of the cylinder mounting bolts and pad retainers. Then I allowed the caliper to soak for two full hours.
After switching out the first caliper for the second I allowed another two hours for soaking. When the calipers came out they had a black residue where the rust had been. I gave them a final wiping and washing by spraying on some Simple Green and then spraying the parts with the hose. I find it easiest to wire parts up to a nearby tree in order to get them clean, allow for good air circulation for drying, avoid touching them with greasy fingers once they are clean, and applying spraypaint all in one location.
I painted the calipers and pad retainer brackets using two thin coats, allowing for 20 minutes of drying time in between coats.
Here are the finished calipers–they came out very nice.