Sam Spaulding

Week 9: Composites - A Lightweight Bowl and Spoon

Composite

Our assignment this week was to design an object, mill a foam mold of it, and use that mold to make a composite object out of burlap fiber and epoxy. I decided to make a spoon and bowl, with the idea that I could maybe use it for camping or hiking.

Designing the Bowl and Spoon I found this to be fairly straightforward, the bowl was made using a simple rotation and the spoon was a linear extrusion with filleted edges, shelled out in the center.



Milling the Mold
Milling took a fairly long time, even though I already knew how to use the Shopbot, because I had a lot of empty space in my mold surface that got cut away and the bowl required a lot of Z motion, which is slow on the shopbot. But at the end it came out pretty nicely, although I ended up making some modifications on the fly to the design, such as adding thicker walls to the bowl.


Fiber, Epoxy, and Vacuum Bagging
I got started on this part of the project early in the morning. After laying strips of fiber down over my mold, smoothing epoxy over them, and repeating for each layer, I popped it in the vacuum bag to cure and harden. Unfortunately, when I cam back, it was stuck! Yes, too much epoxy had been sucked out of my composite and had cured to the bag itself causing the whole object the remain stuck to the vacuum bag! I eventually had to chisel it off, but the top cotton layer remained on the bag. Still, it looked pretty good!