I'm sorry that no one answered your question . This forum
doesn't seem to get any traffic any more.
do a search for cold porcelain.

here is one spot.. scroll down the page and see the video
demonstration. It's a micro wave recipe

Here is a link that might be useful: cold porcelain

I have used polymer clay to make small items. I haven,t heard about making your own, but there are many dough type recipes that might work for you. They usually contain flour. One that you might like has salt and flour and when your sculpture dries, the salt gives a sparkly effect. I have seen Christmas ornaments for sale that were made out of this. I don't know the recipe offhand, but you could easily find it on the internet or in craft books. Coating it with a couple layers of acrylic varnish should protect it. ( This is my first posting, since I just joined today.)