This was a fun challenge!
The writers for Silent Library wanted to hit the contestants with ostrich eggs… but since ostrich eggs are expensive and are so hard that they need to be opened with a hammer, I needed to create some fake ostrich eggs that would make a mess and not kill anyone.
I started by creating a two-part plaster mold from an actual ostrich egg (the egg might have cooked from the heat of the curing plaster, though I never found out since the egg stayed unopened in the refrigerator for the rest of the shoot.)
Porcelain was poured into the plaster mold and left for a few minutes to form a thin shell, and after the porcelain had dried melted parrafin wax was poured into the porcelain shell to make it waterproof. Each of the dozen fake eggs that I made contained the goo from eighteen chicken eggs (thanks to Craig Burghardt for teaching me how to open eggs with one hand, mess hall style.)
The fake eggs were sealed with more melted wax, primed, and then spraypainted. Courtland Premo made a catapult to launch these eggs, and they totally didn’t hurt anyone!