Thanks for the info about the clay.... What intrigued me is that it SAYS it
can be used on a wheel, which makes me think it COULD be gotten wet. Dunno,
still thinking about it. (I THINK there's a wheel in one of the storage
rooms.... An art teacher many, many years before I got there did a lot with
pottery and ceramics, but since then the kiln has been moved, isn't vented,
and all the ceramics supplies have been put away.)
Basically, the kids just used crumbled newspaper underneath the mask (or
hand) and then applied the plaster strips over the edges of the hand and
onto the board. When the plaster gauze dried, the "folds" were permanent so
that it looked like someone was trying to push through.
One of my seniors thought of doing it this way, and then, of course, other
students followed suit.