# 14 - Composites

This week’s assignment was to make a small composite object using resin and fibers. Knowing that I wanted to devote the majority of my time this week to working on my final project, I chose to make something very simple. I made a bowl.

## Design

My initial broad idea was to make a simple polygonal structure. I started drawing in Fusion and decided to play around with heptagons. I quickly opted to make a lofted structure out of two hepatgons at different heights, which started to look like a bowl. I rotated the upper heptagon to offset the faces on the sides.

At this point, I realized that by rotating the upper heptagon the faces on the sides of the bowl were not actually planes and so I would need to triangulate the sides in order to keep the shapes simple and not curved.

I also realized at this point that Fusion wasn’t going to be a great tool for creating a reasonable mesh, so I decided to just draw the few relevant shapes in Fusion, then piece them together in Illustrator. Playing around with the plane construction tools, I was able to create a set of triangular faces to connect one side of the upper heptagon to the lower heptagon.

I had a few false starts getting the right vectors generated, but finally got the sides and bottom vectors into Illustrator with the right dimensions. From there, I was able to match up edges and construct a flat representation on one side of the bowl.

I replicated these vectors around the bottom heptagon to create the rest of the bowl.

## Mold

Part of making the flat representation was that I could make a cardboard mold on the laser cutter rather than going through the process of machining foam. This went off without a hitch and I was able to get a cardboard model put together quickly.

The only problem was that there was very little fabric left by the time I went to do my layup, so this mold wasn’t going to work. I went into Illustrator and resized the vectors, as well as made a version with the faces attached in the other orientation (so that I could cut overlapping fabric on the laser cutter later).

IMAGE: Updated Vectors

I went ahead and cut a smaller bowl.

Then, using both the original and updated orientations, I laser cut the fabric to fit over the bowl.

## Layup

From there, the layup was straightforward. Using the cardboard mold and fabric, I put together a simple 2-ply composite. Unfortunately, it was hard to really get the fabric to stretch well over the mold and none of the sharp edges came through. At this point, I was going to be surprised if the bowl came out looking like much of a design at all.

Nonetheless, I put my composite into a vacuum bag and pulled a fairly strong vacuum through it. I was actually a little concerned that the cardboard may not have withstood the vacuum pulling very well, so I was curious to see what would happen when I pulled the piece out.

## Finished Composite

The next morning I opened the bag to find…

Well, this is undoubtedly the ugliest thing I made this semester, but it did come out pretty strong! Agnes suggested that it looked more like a horseshoe crab than anything else.