Try spraying a thin layer of clear paint. O_O Clear coats are awesome. It holds everything from acrylic paint on t-shirts to the paint on disc brakes and engine blocks. Heat resistant, water resistant, and it doesn't even fall off from shockabsorbers regardless of the constant stretching and compressing. I'm going overboard, but you get the point.
There was this one time I got bored and took the car's wheels apart and sprayed the rims. That's when I realised how awesome clear coats are. Goodbye to the days of paint chipping. It takes a while practising on dummy faces with cans though, but once you get the hang of it, it's awesome. I was sad when I was told dummy face does not mean my brother's face.