10: Molding & Casting

In this class our assignment was to make a mold of a small object that was no bigger than 1”x1”x2”. I was previously going to make a mold of my AirPod case but when I found out that liquid was used to make the mold I promptly switched to a 20 sided die. It had alot of detail that I was not sure would come on the mold but everything turned out pretty well at the end.

Making the Mold

The first step in this was to find a container to put the object in. I chose a paper cup that I cut with a scissor to make it shorter and to stop the die from moving inside it. I superglued one side of the die to the bottom to keep it still so that the silicone mixture covers nearly every face apart from the bottom that had the superglue. We also needed that face to pour the cement mix into (talked about later). After the die was firmly in place, I started to make the silicone mixture. To do this, I poured the Oomoo slicone mixture into a cup in a 1:1 ratio (equal parts A and B) and mixed thoroughly until it reached a light blue color and was smooth with a thick consistency. I slowly poured this into the cup with the dice to avoid any air bubbles from forming and ruining the mold. I used a popsicle stick to make sure that the die was completely submerged in this mixture. This was then left to dry for a few hours. The picture below shows the inside of the mold with detailing after it dried and I had taken the die out.

The Cast

After the mold dried, I made a hole right under the face that was superglued. This was where the plaster/cement mix was poured into. I taped up the top so the mold does not fall out and ruin the cast. The plaster also had to be poured in with extreme caution to avoid air bubbles. We had to pour it in from one side first to allow the air an escape route before it filled with plaster. Some of the plaster overflowed so I had to wipe this off with a piece of paper. I left the cup with the plaster in to dry on my table and I would take it out the next day. I had to give it time to solidify.

The next day I got to class early so I could peel the cup off the mold and take my solidifed plaster out. I made slits on the sides of the blue silicone mold to easily take the plaster out. It came out pretty well with all the numbers coming out detailed and the edges were pretty smooth and fine too. The face that was superglued acts as a stand for the die because it has some plaster sticking out that keeps it in place.