Thanks for taking over Greg. Horrible day at work and I had no time to check in here. While some pros use wax only, I will caution against it. Wax provides slip on a mold (Making it slippery makes the parts come out easier), wax does not provide any chemical barrier. If there is ANY polyester of any sort (fiberglass resin, Bondo, etc) you will experience styrene migration where the mold will not release due to a chemical bond. PVA, when applied properly, will provide the chemical barrier needed to ensure release.
Note that I said use the laminating resin to finish the plug and use the same resin to construct your finished components? Now you know why. If you finish your plug with auto primer, your plug will not stick in your mold and your components will not stick in your mold.
Greg, how new is the purple PVA? Mine is still green. Is this a California thing, or did I just buy old PVA?