I have been working on a new head, built on the principles Nick Hilligoss showed in his wonderful videos. It isn't for animation, but for the head of a staff for a class "Speaking Scepter" -- only the child who holds the scepter can speak. I used a balsa wood core, with eye sockets drilled out, also ear, eyebrow, mouth, nose and neck holes which were filled with epoxy putty so the balsa wouldn't break. Afterwards I covered the head, except for the eye sockets, in a thin layer of epoxy putty. Today I built up the urethane foam, using 1mm foam sheet, first covering the head and then the ears, lips and nose, with cheeks, jowls, brow ridge and zygomatic arches built up with more foam sheeting. He is ready for latex now. I will take some photos and post them as soon as I can pay the light bill and have electricity!
I still have to finish the small head, the photos of which I posted earlier. Have to finish covering it with epoxy putty and build up the foam, then latex. Should be a hoot.