This article has colaboration of Pietro Domingues.
Silicone molds are excellent, because they can be used to make complex geometry objects
with a low cost.
In this section, we will see how to make a silicone mold.
Materials:
Liquid Silicone + catalyst
A container to mix up the silicone
A stick
Another container, if necessary, to retain the silicone with the original workpiece
Original workpiece (Any kind of object to reproduce, the workpiece can be some 3D printed part, or a sculpture, etc.)
There are two kinds of Silicone:
On the right side of the image we can see the white Silicone. It’s made to mold materials at
room temperature, while the brown silicone, on the left, is made for high melting temperature
materials.
There are two workpieces produced by melting them at high temperatures. The first one is
Paraffin wax and the other is Tin.
The rest of the workpieces are made of Plaster of Paris (the white one) and resin.
Silicone comes from factory in liquid state, and it is sold in small containers ( 1L or ¼ gallon).
Before putting into the small container, it is recommendable to stir with a stick to ensure the
homogeneity.
Now drop the catalyst at the right amount (usually indicated on the manual) on the small
container.
After stirring the mix a time (ensure if the catalyst mixed completely), drop the liquid inside
another container with the original workpiece (In this case the workpiece is the container
itself).
It takes about 30 minutes to some hours for the Silicone to cure (it depends on the amount of
silicon). Touch the silicone, if it glues on fingers, it is not good.
After it is ready, remove the Silicone carefully :
Now the mold is ready to use! Let us reproduce the workpiece!
See too:
http://fablearn.stanford.edu/fellows/blog/molds-civilization