PVC pipe works just fine for a spray bar, and as posted above is cheap enough to get some practice in before making the final piece. Also, the sizes and widely available fittings and adapters makes it a pretty good choice for aquarium plumbing.
I have used Krylon Fusion, and I go along with mOOse: Overnight was fine to dry the paint. Maybe it does fuse with the plastic if you wait longer, but I did not wait, and it is holding up just fine.
I did 3 thin coats with a short wait between coats (the instructions are on the can).