Winged dog cast

I finished the mold for the seated winged dog, it took 3 gallons of Rebound 25 rubber and 125# or so of pottery plaster for the shell. I cast the first plaster cast from it tonight, it took almost two 5 gallon pails to fill, and exactly 100# of the Densite plaster.
After hollowing it out as much as I could while it was setting, the wet out of the mold weight is 100#
So if I figure 19 quarts of water used is about 40#, less what was in the waste from hollowing him out, I’ve noticed about half the weight of water used in plaster casts evaporates, the other half stays chemically bound, so the cast pictured should wind up around 85# which means even crated it can ship FedEx ground.