Radiator Question (pic)

I just got my radiator re-cored and I noticed some rust which can been seen when the sunlight hits it. If I spray Eastwood rust encapsulater on it to stabilize the rust will it effect the cooling ability of the radiator?

I'm surprised that the radiator shop didn't give a skim coat of paint over the fins.

That's not rust, it's copper. stand the radiator on it's bottom and with gloss black aerosol paint apply just enough to the fins that they look black when the radiator is in the car. The area between the top and bottom tanks should be blackened using as little paint as possible. I'm surprised the radiator shop didn't do that.

Take it back and have them finish the job!