WEEK 14: COMPOSITES
<- back
After spending weeks debugging things, it was nice to get a break and return to the wonderful world of anything-but-electronics. Maybe someday I will stop hating electronics, but I'm pretty sure it won't happen before this final project is done. Oh well...

I decided to go for "simple but elegant" this week, so I designed a doubly-curved square that could function as a plate or very very shallow bowl to put apples on instead of just leaving them on my desk. I designed the surface in Rhino and then brought it into MasterCAM to set it up for milling.





I milled it out of blue foam, using a long flat endmill to do a rough pass and a giant ball endmill to smooth it out. Calvin and Chris helped me set up the job on the Onsrud (with some bonus advice from Justin), so it went quite well.





Once I got the blue foam prepared, I began the long process of building up layers. I covered it with gesso, let it dry, sanded it, covered it with gesso, let it dry, sanded it, covered it with gesso, let it dry, sanded it, covered it with gesso, let it dry, sanded it, and finally covered it with a few layers of wax, which I buffed with some scrap fabric.



With my mold prepped, it was time to suit up and start laying up. Thanks to Sam for taking this super attractive picture of me! At least who searches me on Google images will know that I care about safety...



I cut out three pieces of the fabric (Jen said two would definitely be too few and four would probably be too many, so I should go with three) and weighed them. I mixed double that weight in epoxy to make sure I would have enough, then mixed it aggressively with a popsicle stick. Jen and Justin had set up a nice plastic covered area to work in, so I put my first layer of fabric on the plastic, poured on some epoxy, and started smoothing it out. I then moved it to the mold and added the next two layers. After the fabric was saturated and smooth, I added a layer of peel ply, a layer of hole-y plastic, and a layer of quilt batting, and then moved it to the vacuum bag. We turned on the vacuum and let it hang out overnight (someone turned off the vacuum after a few hours though).



I came in the next morning expecting everything to stick and be terrible, so I was pleasantly surprised when it came right off the mold and the peel ply released with only a little bit of tugging. It also easily cut with some heavy-duty shears, so I got a nice clean edge. The final product was a bit bendy, but pretty smooth and held up well if weight was applied evenly, so I'm pretty happy with the result. Thanks to Jen, Justin, Calvin, and Chris for all their help!