"Hmmmm. bondo pots Now there's an idea, I imagine one would have to build some type of frame to build the bondo up onto to,...anyhow I will not be trying bondo pots,i'm pretty sure"
You're just going to continue trying to find a magic clay and/or fool around with trying to harden sculpey in your Amana range. Give me a break
Bondo has been used as a filler for old bonsai wood for years. I've used it myself to fill in the interiors of rotting trunks to give living wood some support. I've found it to be durable, workable, paintable, sandable, cheap and available.
Yeah, you have to build a frame to hold onto it, but you have to do the same for cimint fondu--or regular cement--to get any tensile strength. If you don't build a form for the polymers or any other slab/pot that's of any size, like over 8 inches, it will crack or break completely when you pick it up.