Tool generation...
The grinding tool was created by using hexagonal ceramic tiles. The
tile is not glazed on either side. The original mirror blank was
rough ground to approximately the correct focal length (give or take a
few inches). The slightly curved glass blank was coated with about
a 1/8th inch layer of Crisco. The tiles were pressed into the Crisco.
A barrier was then placed around the outside of the mirror blank approximately
1-2 inches above the top of the mirror. Plaster (Hydrocal) was mixed
and poured over the top and left to set. This took several days to
harden. Once hardened, this formed the grinding tool.
Those pathetic frozen pizzas have the perfect sized pans for making
sure that the slurry formed by the grit and water would stay contained.
While cleaning the turntable is not difficult, it could get messy if we
did not constantly make sure the slurry was contained. Additionally,
each time that we need to go to finer grit, we HAVE to get ALL of the old
coarser grit out of the system. A single piece of old grit could mess up
the mirror by causing deep scratches or pits that would have to be
ground out starting with the coarser grit and then moving back toward the
finer grit.
Next we had to clean up the grinding machine...