How to Make a Silicone Polyhedron?

As a high-potential soft material, silicone is always used to explore the plasticity of materials and the space created by it. Here I would like to share my experience of making a dodecahedron by silicone.

The most important part of this work is the fabrication of mould. With a perfect mould, it is quite easy to styling a silicon object. Therefore, this process need a little capability to use a 3D modeling software and 3D printer. People can design a form as complicated as possible, not matter it is streamlined forms or geometry. 3D printer is a great method to fabricated create almost all types of mould.

There is 4 steps in total.

1 a digital file of mould.

2 3D printer, materials: ABS or PLA

3 Silicone Rubber (Ecoflex)

4 packaging tape, mold release agent, measuring cup

It is the most significant step.

There is several key points of the model file.

1 The mould is inverted to the form I want to create. So for the mould, the vacant part is what we need.

2 We need to consider how can we take silicone out of the mould. Thus it is encouraged to separate mould to several parts. I had 3 moulds in this work.

3 For the 3D printer I used, the smallest thickness part of model should be more than 3 mm, or it hard to succeed.

4 The setting of 3D printer is also important. Please follow the instruction book of 3D printer and make sure the surface of mould as smooth and tight as possible. Or silicon can leak from small holes. That what I tested several times.

After the moulds are ready, we begin to fill silicone in the mould.

The whole dodecahedron is divided to two parts, which make it easy to take out off the mould.

First, Fill the same volume of liquid from blue bottle and yellow bottle to two measuring cups. Estimate the volume according to the size of mould. (key point, the two liquids have to be 1:1)

Then, mix the two cups of liquid together well. Please carefully stir it and aviod bubble in the silicone. when the two liquids are mixed, it will gradually turn to solidification. After mixing them, shake the cup carefully to get bubbles out.

Third, spray mold release agent on the surface of mould, to make sure the silicon is easier to be taken off.

Forth, pour the mixed liquid on the surface of mould, it would gradually flow down.

fifth, wait until it solidification. It might need 2-3 hours.

When i get two piece of silicone, then it is the last step: to glue it together.

For silicone product, the silicone is the best glue. So smear residual mixed liquid before its solidification between the edges. Besides, smear on the surface of the junction part to make it sticky tightly.

By the way, all these process sounds simple. Actually, any error in any step may result in a failure. Too many bubbles are fatal. I tried several times to be successful.

Lastly, I added a video to show my assignment about inflation. That is the purpose to make silicon dodecahedra.