This week, we were supposed to cast a mold to create a silicone bibenda actuator. This assignment was definitely challenging for me, as I am not the best fabricator. I’ve included some of my process photos below, along with some notes on what went wrong.
I’m hoping to do a second cast early tomorrow morning to see if I can produced a better second version, because this one was bit of a disaster.
I 3D-printed the inner mold, but foolishly forgot to take process photos.
For the outer mold, I actually found a piece of PVC pipe that was the correct size, but as I had never used a pipecutter before, I decided to cut another piece anyhow.
Proof!:
For a while, I unable to glue the out mold together because I could not open the PVC primer or cement. I had to enlist the help of a friend with a wrench(?).
This is how the outer mold came together:
Next, I cut some stretch fabric to fit it over the inner mold, as per the instructions. There are no words:
I then began to mix part A and B. I realized I was moving too slowly too late. The first degassing can be seen below:
This shows the second degassing. It’s a bit too difficult to see in the picture, but there were way too many air bubbles, and because of how think the mixture had gotten, a lot of it was spilling over the edges. That seemed to be my biggest error: I had allowed the mixture to get too thick by the time I was pouring it into the mold. This meant that 1) it was really difficult to poor into the small mold at all, and 2) I introduced many air bubbles trying to get the mixture inside.
Bit of a mess, but here is the setup at rest:
It did not come out very well. There are VERY large air bubbles near the gaps in the stretch fabric.
If there’s time I’d love to redo this one. I know my error: I took way too long to coat the inner mold, degas, and pour. I was also reading and rereading the instructions to make sure I was doing things exactly right (even though I read the instructions prior to starting, I was a bit paranoid about missing something). Ironically, that did me in.
