Best way to protect water soluble clay dolls?

You could always use the air dry clays for the inner core, and then the apoxie sculpt for the outer layer. But really, as long as you don't let your doll soak in water, it should be fine once painted, as long as the paint is not also water soluble. Even if your doll was, say, sitting on your desk and you knocked over a glass of water onto it, as long as you moved the doll out of the puddle immediately and dried it off, there'd be no lasting damage done. It's not like it immediately turns to mush with contact with water - you can always dry a little lump of clay and put it in water to see how it behaves, but I don't think you have much to worry about unless you want to do photoshoots for your doll in a pond or bathtub or something.

 

Seconding hystericalparoxysm with paperclay core and apoxie skin-- that's exactly what I do. If you're really worried though you might want to try a hydrophobic spray, though as far as I know it's never been done. Might be an interesting experiment.

 

Yep. It works best if you just use the paperclay-type clay to rough out your sculpt and add details in apoxie on top--the skin can add too much bulk to your sculpt otherwise.

Would be neat to see hydrophobic dolls!