A large chicken egg was emptied, washed and covered with a thin layer of translucent clay. (would that i were able to purchase the expensive translucent clay… ha ha… this is Premo) with areas to be removed scored with a knife, and then cured. The early cures i don’t worry too much about time, just enough to make the clay hard enough to work with. (dont forget to poke a hole in the bottom of the clay covered egg to prevent the little “blister” from expanding hot air — this is a nemesis for me, i often forget and then end up patching the bottom).
After the first cure, the areas marked are excavated, but i leave the egg shell within just so that when i cure the egg again and again after rows of colored rope are added, that the original calcium carbonate structure helps support the egg while it cures, if the areas are thin, sometimes they slump. After the initial cure i sanded the holes and added the black rim and cured again. So i just added rows and rows, maybe two at a time until the egg was covered.
After the final cure i removed the egg shell with vinegar (takes several hours and a little scrubbing and sanding), and then used aquathane just on the interior. In this photo you can see just a little bit of the color showing through the translucent base. I bet one could do this without the translucent base, but in my hands, sometimes the pressure cracks the egg…. the larger eggs seem to have less dense calcium structure.