Hi, I have NEVER heard of making your own polymer clay, liquid or solid, I have a feeling that there are just too many chemicals, but I could be wrong!!!
If someone doesn't come by with a good answer soon, please go up to Poly's riendLEIGH Forums and click on Polymer Clay Central, then ask the same question over there, I'm pretty sure you'll get a very fast aswer!!!
Ah!! FOr that there actually is a Liquid Polymer Clay, that you can use for alot of things, which you can buy ready made. It can do many things, including helping to bond raw clay with baked clay, like holding the arms on a doll until its all baked together!!!