Travis Rich -- HTMAA

week 1 Proposal
week 2 Press Fit
week 3 FabISP
week 4 3D
week 5 PCB
week 6 Casting
week 7 ATtiny
week 8 Big
week 9 Input
week 10 Epoxy
week 11 Output
week 12 Interface
week 13 Network
week 14 Machine
week 15 Final

Week 10 -- Epoxy Composites

11/12/12

Introduction

This week we're playing with composites. Let's make something super light and super strong! I started from the idea of wanting to make a 'glove'. A composite that outlines the shape of a hand with spiraling fabric. Something like a boxer's wrap held in place, but without the hand actually being there.

Twine

I started trying to make this hand by wrapping twine. I filled a Nitrile glove with water, tied it off, and laid it flat. Unfortunately, the twine, because of the way it's packaged, had some natural curvature to it that made wrapping the glove quite difficult. After fussing with the twine for a while and realizing it was going to look terrible - I dropped the idea. I decided to move on to trying it with an easier material.

Second Try: Fabric

This attempt I cut lots of fabric strips about a half-inch wide and 8 inches long. I soaked these in West System 105/205 epoxy mix (5 pumps from each). When the strips were sufficiently soaked through, I began slowly wrapping each of the fingers with the thin fabric. This was made easier by the fact that the soaked resin helped the fabric to stick to itself as I wrapped. I kept pressure on the glove to keep water forced into the fingers, giving me a good amount of rigidity to work with. It was rather difficult to wrap some of the undersides of the fingers, as everything quickly descended to a tacky surface, but with a little stubbornness, it was finished. I sealed my bag and connected the vacuum.

On vacuuming, there was the unanticipated effect that the fingers became more squashed that the palm of the glove (I anticipated the vacuum to put pressure on the glove, keeping the fingers rigid - but I didn't anticipate the non-uniform pressure). THis resulted in some of the wrap becoming deformed and the fingers coming out flatter than desired. Also, I had initially intended to pop the glove and remove the excess material, leaving me with the shell of the hand only. Because of the deformation though, I decided that the glove would be a bit nicer looking with the water-glove filling. Not to mention, the hand had a nice feel to it with the glove and composite wrap.

The glove quickly took the role of a high-five buddy. Giving me a friendly outlet for each of my small daily successes.