6. BioFabricating Materials

Crafted materials

This week's assignment was really difficult to complete in an organized way. My work week was really busy and i only had one day where i could be at the lab. This meant i needed to get organized enough that i could just arrive at the lab and execute the recipes. But i didn't know which ingredients were available to me. So i decided to gather a lot of different recipes and to decide which one to make once i got to the lab and had a good visual on the ingredients.

Tools

• Class lecture
• Pot
• Stove
• spoon
• blender
• Scale or measuring Tool
• Molds, textiles, textures

Custom molds

I knew I wanted to try some kind of texture on my material so I started out by laser etching an acrylic plexiglass sheet with some artwork I had.

Here are the laser settings:

Trotec Speedy 300
Material: Cast acrylic plexiglass (etching)

Power: 100
Speed: 40
PPI/HZ: 1000
Passes: 1
Air assist: On
Z-offset: Manual

Download files here¹.

Here i prepped my molds by taping 4"x4" wood frames, which were already made by the lab, that will act as a border when i will pour my mixture. Annie from the lab had a good suggestion to spread some kind of filler into the laser etched cavities, she gave me some charcoal and i sprinkled it onto my mold. I think this will be interesting.

RICE STARCH RECIPE ATTEMPT

There was rice starch at the lab, but i didn't have a recipe for this. However, I did have a corn starch recipe so I decided to follow this one, and switch out the corn starch for rice starch.

As I was gathering the ingredients, I open the rice starch pouch and realised it was not starch, but rice. This meant i had to go through the additional steps of boiling the rice with water and making the starch. I was stressed and pressed for time and couldn't find a clear recipe for this process online. I decided to just keep going, try something and hopefully i will figure it out.

Here i am attempting to make rice starch by boiling an entire 1KG container of rice in a large pot, with an unknown amount of water. (I forgot to document the amount). Then i wrapped the rice in cheese cloth and tried to squeeze out the starch.

Then I tried to follow the corn starch recipe with the starch i harvested from the rice. As you can imagine, it was not a success. It did not solidify and became more like a sticky jelly. I think it might be because the starch recipe ir for powdered starch and i was using a hydrated starch mix.

ALGINATE RECIPE ATTEMPT

In parallel to this rice starch mess, I was also attempting an alginate recipe I found here.

Here's an overview of this recipe:

I slightly modified the recipe from the original and used vinegar instead of sodium chloride because i heard vinegar worked better.

Here i am measuring and combining my ingredients in a pot. The recipe didn't need any heating or boiling, it only called for mixing the ingredients with a hand mixer or blender, and letting the mixture sit for an hour or so to remove the air bubbles.

After letting it sit for an hour, I poured half of the mixture onto a baking tray, mixed with charcoal powder. And the other half, I poured onto my textured mold. I sprayed both all of the mixture with vinegar.

I let it dry over the weekend and came back to the lab monday morning to find the following results:

The aesthetic is really beautiful but it is really fragile, thin and sticky. I don't think it ever solidified. So I think I made a mistake somewhere along the way, probably using the vinegar, which was not part of the initial recipe. Thinking back, i should have also tried a sodium chloride mixture, so that i could compare results, but i din't think of it.

ALGINATE RECIPE RE-DO

I decided to take home some of the lab's equipment so that i could redo some recipes in my own kitchen, at my pace and with a better ability to focus. This time i decided to try Loes Bogers alginate bio foil recipe, changing the ratio but following the recipe word for word.

Here is the recipe:

Here are some process photos.

In this first image, i am gathering and measuring my ingredients before beginning.

Left image: I didn't want to dirty my blender because it's annoying to clean, so i started out by mixing the ingredients in a bowl, but it became super lumpy and difficult to mix. Right image: this is what it looks like once it has gone through the blender, smooth without lumps.

Once my recipe is mixed i poured i into my mold. I sprayed the surface of the mold with the calcium chloride solution before pouring and after. The reaction is different this time, it's instant, it starts to shrink and solidify.

These photos are taken after 3 days of letting my material dry on my molds. The mold textures are very subtle, but they are present. If i had to redo it, i would etch the textures even deeper

GELATIN RECIPE

Now, I'm happy my alginate bioplastic worked out, but i would like to try a bioplastic using a different polymer base. There was gelatin at the lab and i found a gelatin based recipe from Loes Bogers again. You gotta love Loes, she does a great job of documenting, it's very clear and organized.

Here is the recipe i followed, the instructions are recopied from Loes Bogers:

I simply brought the water to a boil and added my glycerin and gelatin.

Right image: I've gathered my ingredients. Left image: I've combined them with water into a pot on low heat.

Once the ingredients are all mixed in i gently stirred on low heat, letting it simmer until it gets to a syrup like consistency. When it feels like a syrup, i took it off the heat, let it cool down for 5 minutes and poured i into my molds.

Here I've poured the mixture into my molds.

This recipe never solidified and I think it's because of the gelatin was sweetened. I did some research into this and found a video that confirms this result. In the video, they try out 3 gelatin recipes. The ratios are all the same, the only difference is the type of gelatin used: neutral sheet gelatin, neutral gelatin powder and a sweet gelatin powder. As you can see at 3:15, the sweet gelatin recipe doesn't produce a manageable plastic.

Grown materials

For the grown materials i was very inspired by the textiles created by root systems which were shown during the weekly lecture. I want to figure out how to direct the growth of the roots into a pattern.

Two bottom images are from Atelier Dasha Tsapenko. Top right is from Bea Fremderman. Top left is from artist Diana Scherer

Tools

• Grow lights
• Black chia seeds
• flat tray, preferrably made of clay
• Mesh or other textile
• Laser cut acrylic mold

Process

I wasn't exatly sure how to go about this as i couldn't find any instrucitons online for how to do this. So my instructor Annie recommended i do a rough trial where i place different things at the bottom of a tray, and try to grow something onto it. I thought that was a good place to start. I also decided to use chia seeds, since i could easily buy it at the local grocery store.

Left image: I've gathered a few things from around my house to place in the bottom of a tray. There's textiles with different structures: A knit with laser cut holes, a very open gauze, a felt, a piece of gourd sponge, an empty pack of gum because it has recessed shapes I am curious about, and magnets (i don't know why, just curiosity i guess). Right image: I've sprinkled some chia seeds all over the plate, misted with water.

I found some an instructables post on how to sprout chia seeds and loosely followed this. They recommend covering the seeds, so i covered my plate with something that would let the light through, clear cling wrap. I got some grow lights from the local hardware store and set up a spot on a shelf where i could let it do it's thing.

Here I check up on them every now and then:

After 3 days, the sprouts aren't coming in yet, but i can see some roots starting to form.

After 5 days, the sprouts coming in, but i notice that the roots are starting to rot and some mold spores are starting to form in various spots so i decided to abort it at this point.

Results

Material pic	Material	Observation
	Woven wool	The chia seeds did not sprout
	Gauze + plastic with recessed shapes	Some seeds have sprouted (not all), the roots penetrated through the gauze and the roots arranged themselved in the pattern of the plastic container. Promising! But the roots are a rotting
	Gourd sponge	Some seeds have sprouted (not all), the roots penetrated through the grouds structure. A lot of mold growing on this sample
	Cotton fleece	Half of the seeds have sprouted. The roots have penetrated the material through the laser cut holes only.
	Felt	Most of the seeds have sprouted on this one. The roots have not penetrated the material.

New trial

Based on the rough trials, I decided to redo another round and use a plexiglass mold (i created during the soft robotics week: download file here ²) in the same way i used the plastic gum package. That first trial was not perfect because the roots were rotting, but I'm not sure how to fix that yet, so one thing at a time.

I'm placing a 3mm thick plexiglass mold with an intricate design at the bottom of a glass tray. I layed a mesh fabric on top of the mold and apply a mixture of chia seeds and water. I placed in under the grow lights, but soon i noticed that the fabric started to curl up as the chia seed mixture dried. To fix that, i tensioned the bafric and secured it with bull clips.

Results

Coming soon

Fabrication files

---

1. Texture on acrylic ↩

2. Voronoi Mold ↩