For Surface Prep –
You can also just wipe the pieces down with PVC cleaner, the type you use before glueing it together. Smear it out wipe it off with a rag.
Even if you were to sand it, the finish still needs to be cleaned with thinner or cleaner to get rid of the contaminants that have come up out of the PVC.
Once cleaned it doesn't matter what you use. It could be acrylics or thinned down solvent based even rustoleum.
Another fabulous post from the U.S.Department of Wild Imaginings, now in spectaclar stereo, sponsored by the Adhesives and Sealants Council, suggesting ways to stick things together since the 1800s. Not fabulous in a gay way. Your results may vary. Illinois residents add 8% sales tax. These posts have been made by professional post makers, do not try this type of posting on your own without extensive training, lovely assistants and a trusty clown horn.