week 4
Bio Plastic
Assignment | 17 oktober 2017
Explore (at least):
- 1 natural dye or bacterial dye
- 1 crafted or grown material
- Order, display, map & credit the process and results.
ref.: http://fabricademy.fabcloud.io/handbook/classes/03_biofabrics.html
Bootcamp
In the Bootcamp a week prior to the Fabricademy we did our first bio plastics experiment in preparation for the course.
Conclusion; We tried 4 different recipes, of which 2 were gelatin based. Which I experienced as a very disgusting intense smell which lingers for about a week or so. Hence I'm not to keen on trying that again. The result of the test was, yes confirmation, that the bio plastics sticks to wood and paper (regardless of the recipe) and can not be pried loose without doing damage to the cast. The second thing that stood out was the amount of shrinkage. We left the pieces drying for over a week. Most of the thinner bits were all curled up. The thicker bits like the squares, the bird shape and the plane shape were still recognizable but due to dehydration turned very flat. The leftover material that was poured into a plastic cup took a extra week to dry and lost it's shape completely.
Since that was my first time learning curve, the goal for this week is to focus on 1 recipe.
Research Bioplastic
What is Agar Agar?
FAQ
Project inspiration
Agar shrinkage experiment.
Based on how solid the dried experiments from the Bootcamp week were, I am wondering how this material will respond when carved with a milling machine like the Modela. Because the Agar we had available was only 250 gram (and locally expensive), we chose to go for a recipe example with a high percentage of water and a low usage of Agar. For this experiment I laser cut 3 boxes (makercase.com) with a measuring tape engraved on the side. When the casts turned solid enough to lift them out of their boxes I flipped them over every once in a while, to give both sides a chance to dry.
- Recipe 1: 4 gr Agar agar, 100 ml glycerol, 60 ml water.
- Recipe 2: 8 gr Agar agar, 100 ml glycerol, 60 ml water.
- Recipe 3: 12 gr Agar agar, 100 ml glycerol, 60 ml water.
After 4 day's - still not dry.
After 7 day's - only recipe 1 still not dry.
Conclusion; all 3 recipe's shrunk to about the same size, roughly to 1/4 of it's original size. Though hard to see on the photo, there is a slight color variation between the 3 pieces. Recipe 3 being the darkest. You can also notice the difference in how curly they turned out. Recipe 3 dried the 'quickest' and curled the least. They vary slightly in thickness, recipe 3 being the thickest. All 3 have started to mold, recipe 1 the most. But despite all that, the recipes turned into a solid material. And if it did not crull up so much it would be worth a try to put in the cnc mill.
To continue the experiment I would recommend to add more Agar to the recipe and try out different way's of drying and prevent the material from curling so much.
Agar re-hydration experiment
I was wondering how the Agar would respond by getting wet again. And if by soaking it shortly, I could bend it more flat. Making it a bit wet did not have a direct effect, so I let it sit in a small puddle for a few day's. The Agar responded like a sponge, soaking up all the water. The color receded back to white-ish transparent, where it was sitting in the water. And the molds that where already starting to form on the piece accelerated into bigger ones.
Agar & laser
I engraved a photo of the Agar plant on top of the dried Agar bioplastic (and I chose to not spend time on editing the image beforehand). Engraving works just fine, laser setting is 600 DPI / Speed 100 / Power 50. Though the image was too low in contrast to recognize what is on the engraved version. I repeated the job with 300 DPI & brightness filter a couple of times on the same spot to try and improve it, but that only helped slightly. Vector cutting was also fine. The laser setting is 600 DPI / Speed 30 / Power 80 / Feq. 500. The problem with my sample pieces is that there is not really a flat surface to cut on. So I broke down a piece into flatter bits. If I would try to cut it in its unbroken state, I would have to mount the other lens (longer focal point) first, otherwise there is a high chance that the auto focus pin will be bumping the (curly) bioplastic.
Agar mixed with stuff experiment
With recipe nr 1. we tried casting in a silicone mold. It was no problem getting them out of the mold, so the bio plastic does not merge with silicone. With these cast I tried what would happen if I add various items to the cast. We tried adding pieces of plywood, MDF, screws and LED's. When the bio plastic was setting I pushed stuff in. The bio plastic was solid enough within 15 minutes or so, and looked quite nice for about a day. After that the shrinkage started to deform the shape.
4 day's and counting - still shrinking.
After 7 day's.
shrunken, but still nice when LED is on.