Silicone-Nitinol Mashup

John Kestner - Techniques for Design and Fabrication, Fall 2008

For my composite material assignment, I decided to play with silicone and nitinol since I hadn't handled them before and wanted to get a feel for the properties. (Click on a picture to see more detail.)

  1. I mixed up some Dragon Skin silicone and poured it into a small plastic cup and spread on wax paper.
  2. I embedded some pre-shaped nitinol wire into the cup and coiled it several times. I didn't know exactly what would happen - I was hoping that the nitinol would be strong enough in several windings to do something (I was wrong).
  3. I also spread a nitinol wire into the silicone on the wax paper, hoping to drape a skin over the wire as the silicone dried.
  4. After the silicone dried, I applied voltage to the nitinol in an attempt to get it to move. I was hoping that it would pucker as it tried to straighten out, but it didn't do anything except get hot. Way too thick.
  5. I had more success with the thin layer of silicone. After seeing that it didn't dry around the wire like I wanted it to, I just used some extra silicone that had dried in a sheet on the wax paper. Draped over the nitinol on both sides in a thin layer, it was flexible enough to allow the nitinol to move when current was applied.
  6. The gauge of wire I used was just way too thin to create enough force to do much, but I could crumple this messy structure into a ball, and with current the nitinol would gradually unfold it into a flatter structure.

    If I had had more forethought and time, I would've gotten thicker nitinol that I knew which shape it would take, perhaps thinner silicone, and laid it out in a prettier pattern. I did get familiar with silicone and intend to use it to give future projects that creepy human touch.