I've worked with PVC pipe a bunch in the past and there's one thing that stuck in my mind. That stuff generates static electricity like there's no tomorrow.
So today I tried coating boolits in a scrap piece of 4". Stuff works like a champ! I used it to coat the dirt boolits in my other thread I posted today. I'm going to have to pick up some more 4" and try it with some yellows since they don't tend to work so well.