People often wonder how tactile pictures are made. There are lots of different ways to make a mold for thermoform reproduction but the technique I use most frequently is to sculpt clay and then cast it in a heat resistant, flexible plastic.
Photo One:
This is a photo of the finished clay model of a bat. It is very low relief. It shows the belly of the bat. I chose this view of the bat because it makes the relationship between his mouth, eyes and ears visible. It also clearly illustrates his legs and wing structures. My favorite tools are shown. The micro spatula, which is a small stainless steel tool shaped like a round-cornered rectangle with a handle on it is to the left. The small clay loop is a wire loop attached to a handle, also on the left. On the right side of the picture is a small wooden clay tool with a diagonal cut on one end and a rounded form on the other.
Photo Two:
After the clay sculpture is finished I pour plaster over it to create a negative plaster mold. Once it is dry I can lift it up and pull the clay sculpture out of the plaster. This leaves a perfect negative impression of the sculpture behind. I can then turn the plaster so that the cavity is on the top side of the plaster, mix a two part plastic casting material together and slowly pour the plastic mixture into the mold before it starts to harden. I use Smooth-cast 60D made by Smooth-On http://smooth-on.com
Photo Three:
Once the mold is filled I level it off with the straight edge of a ruler. This is the messy part! Then it must sit for about 20 minutes while the plastic hardens. This plastic is thin and transparent enough to somewhat make out the body and the out stretched wings of the bat.
Photo Four:
After the plastic has set I can pull the plastic mold out of the plaster and trim all the excess plastic from the edges of the casting. This bat is now all ready be to shipped to National Braille Press to be used as the mold for the thermoform tactile graphic inserts in the book titled, Bat Loves the Night by Nicola Davies http://www.nbp.org/ic/nbp/BC1409-BAT.html
