with Rallysman, and if you need to - ruff up the pvc surface with fine sand paper or a scotchbrite pad.
The laziness in me kept me from going that extra step. I had expected a better bond and am now dealing with some white spots in my black painted PVC. It does not peel or flake, but it scratches off easily. I used PVC cleaner on the bare pipe and let it dry (I had hoped to enhance the chemical bonding). It will be well worth it to hit it with fine sand paper.