I paint mine with Fusion paint for plastics, or I use a plastic primer first and then a spray paint of my choice. I let the ball cure for 2 weeks per the can instructions, then I spray 3-4 layers of an outdoor clear poly on it and let that cure for another day or two, then it can go outside. I also spray it with clear poly every spring and bring them inside for the winter as they could crack depending on what the ball was made of. Make sure you get the waxy coating off the ball first by washing it with a 50/50 vinegar/water solution or rubbing alcohol.

Here is a link that might be useful: My Bowling Balls

Oh heck...I just use any kind of spray paint. I've never had any problem with the paint coming off. Just wash the ball well before hand. I've used dish soap and one of those green scrub pads.

Or better yet, buy pretty swirly colored balls!

One other tip for you. If you go to a bowling alley, they will probably give you the BB for free. I wanted to do a project with the cub scouts, and they were more than happy to give the BB away. Aparentlymany people leave their old ones behind when they get a new one.