For my final project, I wanted to use composites week to create a sturdy base for the projector in the shape of a morningstar. I used Fusion to design a base that would be beautiful, reference geometric forms within the shape, be easy to use with a 2D mold, and have a flat, higher surface for attaching hardware.
I knew that there would be some loss of detail from the original design from both the shopbot milling process (in which I used a 0.5" rounded botttom mill) as well as the layering of the thick burlap (I used three layers to increase stability).
The milling process went well. With Tom's help, I was able to create accurate tool paths for the roughing and finishing paths. I glued the 2" foam insulation together in layers to ensure a deep enough material for cutting.
I decided to keep the foam in one piece so that I can use it later for other molding processes, so I did not trim it down. I began folling the process TA Grace laid out. I mixed the epoxy and hardener in a 100 to 43 mixure, and after putting a plastic wrap underlayment to ensure mold release, poured it on the mold. I had cut out three morningstar shapes roughly in the shape where they would be placed on the mold. I had played around with using the Exactflat soltware and mulled using the lasercutter to cut darts in order to make the detail more visible.
In the end I decided to see what happened just using the basic process. This week's lesson is one of those that, as an artist, I will definitely use in the future. This being my first time using this method, I wanted to start off at the basic level, so I can troubleshoot and learn which methods will work best for me and my process.
I layered the epoxy in between the burlap and squeezed out excess expoxy. This was difficult because it was welling up in the mold. Then I placed the red breathing layer film and wrapped the whole thing in the cotton batting. I placed it into the vacuum bag and used the air compressor to suck out the air.
The exothermic reaction caused the epoxy in the mold to become quite hot, and I worried that it would actually melt the plastic. Thank goodness it didn't. After waiting 24 hours, I opened up the mold to see what had transpired within.
The post processing phase was actually quite difficult. I received several small cuts on my hands when I removed the star from the mold and the plastic underlayment from the mold. I wore gloves after that. I think there was excess epoxy that caused the surface to be uneven. The next step was trimming down the star edges, which I did with a hand saw and then, i applied a layer of gesso as a primer for painting. Grace suggested I experiment with sparkles in the surface treatment, so I will paint the surface to coordinate with the projector and add sparkles to the final piece.