Mold and Cast of BJD Knee Joint Ball Part with Magic Sculpt

What am I trying to do here? I need to make a mold for this part (double balls for knee joints) - see the photo just below. I need a part, consisting of 2 balls, which are  connected, flattened on each side, with the vertical central hole. Why can't I just roll some clay in…

bjd — News — STAND

Mold and Cast of BJD Knee Joint Ball Part with Magic Sculpt

How to Make a Ball Jointed Doll (with Pictures) - wikiHow

bjd — News — STAND

Mold and Cast of BJD Knee Joint Ball Part with Magic Sculpt

Ball Jointed Dolls

I want to make my own BJD

I want to make my own BJD

Ball Jointed Doll Mold - Sweden

Cast Resin Simple BJD Parts or Doll - Sculpting Reference, makingfairies

Molding and Casting A Ball Jointed Doll