BTW, have any of you tried the IOD Moulds? IOD=Iron Orchid Design (I think). Some of the molds can be expensive but they're very sturdy with great detail. I got most of mine thru Amazon. I've been playing with those using air dry clay, paper clay, and resin. Their Facebook page of followers has posted some super inspiration photos of their creations.
I placed the castings over clear plastic ball ornaments:
I have a few recycled plastic pots ready for a few clay castings. My main goal was to create castings from papercrete to add to my pots. This is so exciting for me!