by Eldy Lazaro
Difficulty: Intermediate
Duration: Active Fabrication: 2-3 hours; Drying: 24 hours
Introduction
Bio-based materials enable more sustainable devices and wearables, and furthermore, their properties offer novel design possibilities beyond the current scope of conventional materials. This tutorial explores an affordable and accessible fabrication method to make soft biofoam strings with the aim to resemble yarn-like material. We speculate how to use this soft material to make "Dissolving Wearables", however, we believe their application could be expanded as a material for soft robotics.
Prerequisite & Background topics
Before starting the tutorial, you can familiarize yourself with prior research, material, and design exploration done with biofoam. Feel free to browse the resources linked under each item:
• Fabricademy - Bioplastic Cook Book (link)
• Loes Bogers - Biofoam Molding Tutorial (link)
• Miriam Ribul - Recipes for Material Activism (link)
Video preview
Equipment
• Silicon spatula (link)
• Electric hand whisk (link) or regular whisk
• Silicon mat (link) or another non-stick surface
• Piping Bags and Tips Set (link)
• Scale, measuring cups, spoon, scissors.
Pre-instructions Follow step-by-step instructions on how to make the biofoam base mixture described in Appendix A.1, steps 1-7, in the paper "Exploring Biofoam as a Material for Tangible Interaction".
Fig 1 visually shows the consistency or viscosity in which the base material mixture can be stored in the fridge for later use to make various biofoam iterations. We stored the mixture in a Glass Jar with Airtight Lid for up for up to a month without seeing sings of mold growing inside. |  |
Note: The cooking time can vary based on the amount of material you are making. From 20 minutes when using the amounts on the table (Fig 2) to 2 hours when making a batch of 1 liter. Expect the yield of the base mixture to reduce to a third of the starting amount. |  |
Preparation In this tutorial, we will use the base material mixture as the starting point to make various iterations of soft biofoam strings. 1. From a big batch of the base mixture, weigh 100g of it and place the chunks of material in the pot at 180F (80C) and constantly stir. |  |
2. Let the chunks of material melt until achieving a syrupy consistency. Note: A way to test the right consistency is to scrape the spatula across the bottom of the pot and it should leave a trace that takes 2-3 seconds to close. If the mixture in the pot ever reaches a boiling point, reduce the heat level. |  |
Optional: For color, add natural pigments or food coloring to the mixture. If using pigments (powder), start by adding small amounts of 2g at a time until achieving the color intensity you want (Fig 5). If using food coloring, start by adding 1 drop at a time. In both cases, stir until you get the color uniformly throughout the mixture. |  |
4. Then, add 3g of liquid dish soap (the foaming agent) and stir until you get it fully mixed (Fig 6). 5. Transfer the mixture to a smaller container to make it easy to whisk. |  |
6. Whisk the mixture for about 1 minute or until achieving a meringue density (Fig 7). |  |
7. Prepare the piping bag and pour the mixture on it (Fig 8). If you are not experience with piping, we suggest you to start filling up the bags with small amounts of material. For instance, half its full capacity. |  |
8. Set up a non-stick surface such an acrylic sheet. 9. Start piping biofoam strings! (Fig 9) 10. After 24hours, peel off the strings from the non-stick surface and store them as you prefer. We used cardboard yarn cones to store ours (see header image). |  |
Variations and things to try
Alternative piping tips for texture Play with texture and scales using various piping tips. The kit we bought had 55 different ones! Although, depending of the meringue density some forms can be achieved better than others. Different piping tip sizes will help you achieve different string thicknesses. |  |
Varying Color Experiment with color shades by testing out different amounts of pigments or food coloring drops. You can achieve multiple palette of colors! |  |
Make new biofoam from scraps For the hand-on session at DIS 2023, we will start using biofoam scraps! Add a stream of water to the pot, then add the chopped biofoam and stir until all the material is evenly melted. Then, start from step 6 of this tutorial. |  |
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Post-requisite topics & Going beyond
We just got our Design Exhibition paper accepted at the ISWC 2023 conference.
The paper explores the integration of this material in wearable pieces where dissolving is an intentionally design quality in the garments. A pre-print of our paper can be found here.
Other interesting resources to learn more about bio-based materials and their applications in and outside the HCI community:
• Fabricademy Lecture - Biofabricating Materials (link)
• Paper - Designing Interactions with Kombucha SCOBY (link)
• Paper - Myco-accessories: sustainable wearables with biodegradable materials (link)
• Paper - From Plastic to Biomaterials Prototyping DIY Electronics with Mycelium (link)
Acknowledgements
Thanks to Kerstin for helping with the biofoam base material preparation and piping; Lily for the biofoam plying; Shanel and Mika for being open to use the material and incorporate them into garment pieces; Sasha for the conversations and reflections about ways to use the material; Laura and Mirela for their advise and support to my research and work.