For this project we needed to create a mold that in order to cast some 3D shape, my partner and I decided to create an icosahedron. Our first step was to find an STL file of an icosahedron. We then created a series of toolpaths that would cut out the design.

This is what our block of wood looked like after the first path with the CNC mill. As can bee seen the shape in the middle is very jagged and needs to be cleaned. Additionally there are squares cut out of the base on the right hand side and squares protruding from the wood on the left. These are ‘keys’ and I will explain their purpose later.

This is the final cut-out shape. The keys can be seen quite clearly here as well as the final shape coming from the top of the object.

Our next step was to create a mold of the shape with a material called oomoo. We first raised the walls with playdough in order to create a good base for the mold, then poured in the oomoo and allowed it to set for about 90 min. We created two of these molds.

These are our final molds. We next put them together, using the keys to ensure that they are put together smoothly with minimum shifting.

We held the molds together with rubber bands, then used the orange funnel seen in the picture to pour in a material called 300Q. The funnel was necessary because without it the material would pour in too quickly and air pockets would form within the mold. We also added dyes to the 300Q to create different color castings.

These were all of our attempts. The red and blue casts that are in separate pieces were the result of the air bubbles forming within the mold The yellow casting didn’t form completely due to a lack of material. The red, blue and black castings were our final casts. As can be seen they had a sort of ‘pedestal’ underneath which formed when excess material was poured into the ‘funnel’ on the top of the oomoo.

Finally I simply cut off the ‘pedestal’ and sanded down some of faces to create the final project that can be seen above.