In order to do this, I had to create a plug, or core, that would allow wax to come in and form the "metal" of the helmet, while at the same time maintaining the empty space within the helmet also-- thus creating a thin wax helmet which looks like the real thing.
I used an even layer of clay to form a stand-in for the helmet itself, and then poured wax into the empty space to create the core:
I removed the clay piece and set the core back in place--
After pouring wax down in between the cracks and letting it cool, out came the helmet form...
By the end of the day, I had a workable helmet form.