RE: Making a glass cowl from the inside of a plastic one ?
PVA stands for polyvinyl alcohol. It's primary job is to create a barrier that prevents any chemical reactivity between the release surface and the layup resin.
I like to use Part-all Paste #2 release wax and Part-all Film #10 (PVA). I've never tried to release off of ABS so I'm giving you the safest release combination. Wax alone may work but I think you might run into problems depending on your chosen resin. You should test your chosen combination on a scrap first.