Believe it or not, this was the toughest part. I recently figured out how to make latex molds so I figured this would be easy. I carved four spikes from 1" wooden dowels and made a latex mold. I then got some 2-part 8lbs polyurethane flexible foam, mixed and poured. This approach worked fine when I was making skulls with ridged foam. The problem I discovered is that flexible foam is really hard to get out a a mold. It sticks more than the ridged foam and, since it flexes, there is nothing to push against. After ripping apart two of them, I just cut the others out, thus destroying the mold. I also found that this stuff is almost impossible to sand, so get the shape right or plan on using scissors.
So, I went to plan B and decided to do a two-part plaster mold of the spikes. Making this mold is not as easy as it looks but it isn't over the top difficult either.
Fortunately, I had one skull already completed and, just for fun, I painted a couple of the spikes and pushed then through the eye-sockets. Oooooh! I couldn't walk away. So, I went back to the latex, but this time, I used a thin line of clay jutting out from the wooden dowl so that I could make a seam. This seam would let me peal off the mold without cutting it. I used some binder clips to keep the mold closed during casting. Not perfect but acceptable by my standards.
I used scissors to trim the seam and to cut them all to the same size. Several rounds of this, a litter copper spray paint and a Velcro pad sown on the end, and I have my 26 spikes.
