week 10: composites

This week we learned how to work with composite materials, or materials that are composed or two or more different materials in order to get a composite material that combines the best of the individual materials' properties. For example, concrete alone is strong under compression, but weak in tension. Likewise, rebar is strong in tension, but not in compression. Mixing rebar into concrete, however produces a material that is strong in both tension and compression.

Specifically, we learned how to work with epoxy-infused fabrics and how to vacuum-form them over objects to produce a light-weight, but strong shell. For my project, I decided to make an iPhone case. Not wanting to risk ruining my own phone, I 3D printed an iPhone4 using a model I found online.

I then molded and cast a second iPhone4 so that I could make two cases at a time.

I wanted my case to have a little pocket for my ID card, so I glued on a scrap card I found to the backs of the phones. I cut off a thumb-sized section at the top of each card so that the final case would allow the actual ID card to stick out a little bit.

To make the case prettier, instead of using the stock beige linens we were provided, I bought a cheap buttoned down shirt at the Garment District with a colorful pattern on it, and used that as my fabric base.

I then cut it up, mixed the fabric with some epoxy, spread it out over my phone models, then vacuumed-formed it!

Removing the phones was fairly straight forward, though despite my excessive use of mold release, the Drystone-cast phone got stuck to the fabric and ruined the case.

With a little bit of manual labor, I trimmed away the extra fabric and drilled holes for the camera and other buttons.

The problem with the case, however, was that it would not clip to my phone. Since I formed the fabric over the phone while it was completely flat against the table, the fabric wasn't able to get underneath the phone and create a lip to hook onto the phone. So I redid it, this time propping the phone up a little bit using scraps of acrylic.

This worked much better, and now I have a functional iPhone case!