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Material Recipe tests

I tested out various recpies to create biopaste that would be extrudable. The best potential results are

1 : Gelatin + Cellulose
2B : Agar + Cellulose
7C : Starch + Cellulose

Observations :

  • Gelatin: elastic, reheatable
  • Agar: snap-sets, friable
  • Starch: extrudes well, slow thickening
  • Cellulose: helps extrusion, holding form

Raw Materials and bulk preps

I prepared some of the ingredients in bulk since they were going to be used in multiple recipes

  • Gelatin, dry
  • Cornstarch
  • Cellulose (Tissue paper pulp, blended, drained)

Gelatin alt text alt text alt text

Cellulose Preparation :

1:10 :: 40 gm tissue : 400 ml water

  • measured 40 gms of dry tissue paper
  • added 400 ml of water

  • using a home mixie to blend as far as possible The material still clumps, and in the vessel it feels a little like cottage cheese with some water drained

  • used hand blender to blend further

  • the whole mass is cloudy. It still forms crumbs if I pinch it and roll it in my fingers, but otherwise is quite loose

  • 10 gms of dry cellulose was about 65 gms of moist blended and squeezed mixture

  • store in an airtigjht container in the fridge

  • Ball drop test was a success - It blooped a bit and got a flat surface but did not break apart or splatter. It is holding together a little like dough but it's also slightly crumbly, not entirely clay smooth.

Gelatin preparation

1:5 :: 62 gms gelatin : 300 ml water

  • sprinkle gelatin on water
  • let it "bloom", it forms a gelatinous mass by absorbing all the water
  • do not count this water in the recipe water qunatity
  • do use the 1:5 ratio to weigh the gelatin later, i.e if the recipe calls for 2 gms dry gelatin you need 10 gms bloomed gelatin from your preparation
  • i heated some water in a saucepan and placed a container of bloomed gelatin in it when it was time to liquify and use the gelatin properly
  • store in an airtight container in the fridge with clingwrap, etc touching the surface of the material to prevent it from drying out

Cornstarch preparation

1:3 :: 15.5 gm cornstach : 46 ml water

  • mix the two into a slurry
  • store in the fridge until needed
  • heat and cook later as needed

Recipe 1 - Gelatin + Cellulose Paste

Use: primary extrudable, elastic, reworkable paste

Ingredients

  • Gelatin: 20 g
  • Cellulose (dry basis): 15 g
  • Water : ~100 ml
  • Glycerine: 2 g (10% of gelatin)

Steps

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Gelatin bloomed, dissolving

  1. Bloom gelatin in cold water (5–10 min).
  2. Heat gently (45–50 °C) until fully dissolved - I placed the vessel in a saucepan of water on the stove. The double boiler method prevents too much heat.
  3. Prepare cellulose pulp separately; squeeze to damp.
  4. Combine warm gelatin with cellulose gradually.
  5. Add glycerine last.
  6. Mix until homogeneous.
  7. Rest 5–10 min.
  8. Extrude warm; reheat gently if it stiffens.

Results

  • Initially runny : I added 3.5 gm of glycerin by mistake !
  • Later : Too hard but holding shape
  • Immersed bottle in warm water to soften it up - works
  • Extrudes well

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Bottle immersed in warm water

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First Extrusion

Later extrusions after 24 hours
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Observations

  • Glatin based, so can be reheated and reused
  • stacks well, builds walls
  • initial set is in a few seconds as it cools, then longer drying period

Recipe 2A - Agar + Kaolin

Use: : fast-setting

Ingredients

  • Agar agar: 3 g
  • Water: 100 ml
  • Clay (kaolin): 15 g
  • Glycerine : 1 ml

Steps

  1. Disperse agar in cold water.
  2. Heat to near boil until solution is clear.
  3. Reduce heat; add clay gradually, stirring continuously.
  4. Add glycerine if using.
  5. Transfer immediately to bottle/syringe.
  6. Extrude within 5–10 minutes (sets on cooling).

Results

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  • I did not make a slurry of the Kaolin to add to the agar, so initially it was difficult to mix in

  • Then I made a slurry of the remaining half of the Kaolin and added but apparently I used too much water and the whole thing became very runny.

  • To counter this, I added further 3 g of Kaolin

  • And 0.5 g of Agar

  • Heat

  • It is a runny mix, that sets very fast.

  • It can't build height since it's very runny and spreads, and by the time it has set enough to hold a layer above it, the stock mixture sets as well.
  • Agar sets on a temperature gradient, not by curing. So it will all set very suddenly when the temperature is achieved.
  • It sweats a lot of water, so its almost permanently wet
  • Extremely friable - brittle, breaks off easily, no strength

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  • A while later, a lot of the thin sections had broken up, I am guessing the shrinkage was pulling them together but the surface friction of the base material on which they were extruded did not allow the shrinkage, so the strands fragmented.

Recipe 2B - Agar + Cellulose

Use: : fast-setting, extrudable

Ingredients

  • Agar agar: 3 g
  • Water: 100 ml
  • Cellulose: 5 g (dryweight equivalent) or 37 gm soaked and squeezed
  • Glycerine : 1 ml

Steps

  1. Disperse agar in cold water.
  2. Heat to near boil until solution is clear.
  3. Take the cellulose in a mixing bowl and break it up, disperse it.
  4. Reduce heat; add agar to cellulose in a bowl gradually, stirring continuously.
  5. Add glycerine if using.
  6. Transfer immediately to bottle/syringe.
  7. Extrude within 5–10 minutes (sets on cooling).

Results

  • works well - is smooth and creamy
  • extrudes decently, builds walls
  • cools solid quite quickly like all agar mixes

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Recipe 2C - Agar + Expired POP + Coffee Grounds

Use: : fast-setting

Ingredients

  • Agar agar: 3 g
  • Water: 100 ml
  • Coffee grounds : 5 g
  • PoP powder : 5 g
  • Glycerine : 1.5 ml

Steps

  1. Disperse agar in cold water.
  2. Heat to near boil until solution is clear.
  3. Reduce heat; add agar to coffee grounds in a bowl gradually, stirring continuously.
  4. Add PoP powder as well.
  5. Add glycerine if using.
  6. Transfer immediately to bottle/syringe.
  7. Extrude within 5–10 minutes (sets on cooling).

Results

  • sets fast like all agar based recipes
  • no height build up possible, too runny, flows
  • coffee grounds being uneven occasionally clog the nozzle

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Recipe 4 - Gelatin + Bagasse Composite

Use: coarse, fibrous extrusion (low detail)

Ingredients

  • Gelatin: 10–20 g
  • Bagasse fiber (processed): 5–15 g
  • Water: 200 ml
  • Glycerine: 5–10% of gelatin weight

Steps

  1. Chop bagasse finely.

  2. Boil with water + 0.5–1 tsp washing soda per liter (20–30 min).

  3. Rinse thoroughly; grind while damp.

  4. Bloom and dissolve gelatin separately.
  5. Add bagasse gradually into warm gelatin.
  6. Add glycerine.
  7. Rest 10 min.
  8. Extrude with large nozzle.

Bagasse prep :

  • chopped the bagasse to 10 mm pieces
  • soaked them in water
  • boiled for 30 mins with a pinch of washing soda

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The bagasse needs grinding, since it's fairly stiff and hasn't softened up too much. I am not sure if the final paste will be useful, given it's coarse texture.
Currently pausing here.

Recipe 5 - Sodium Alginate + Cellulose

Use: controlled extrusion with post-setting

Ingredients

  • Sodium alginate: 2–3 g
  • Water (RO/distilled): 100 ml
  • Cellulose (dry basis): 5–10 g

Steps

  1. Sprinkle alginate slowly into water while stirring.
  2. Rest 10–15 min until viscous.
  3. Add cellulose pulp.
  4. Mix gently; rest 5 min.
  5. Extrude.
  6. Set later with calcium chloride if needed.

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The Alginate I have did not initially thicken up the water when added to it. I added more, and it eventually set into the usual alginate gel form.

There are multiple things happenning here that I need to untangle before I can proceed :

  • I am using molding alginate used for body casts, etc which may have a calcium component mixed in that makes the alginate set
  • The alginate is old so may have aged somewhat
  • The water has a calcium component that makes the alginate set

I need to try

  • fresh alginate, ideally the molecular gastronomy grade so there's no Ca component
  • RO or Distilled water, so no Ca in water either

Pausing for now until I get either or both of these.

Recipe 7A - Paper Lace (Starch + Cellulose, Flowing)

Use: paper lace, sheets, surface drawing

Ingredients

  • Cellulose (dry basis): 10 g (67 gm wet squeezed)
  • Cornstarch : 3 g
  • Water : 90 ml
  • PVA glue: 8 ml
  • Glycerine: 2 ml

Steps

  1. Slurry starch in 20 ml cold water.
  2. Heat until translucent.
  3. Mix starch gel into cellulose pulp.
  4. Add remaining water gradually.
  5. Add PVA.
  6. Add glycerine.
  7. Rest 5 min.
  8. Extrude warm (will spread).

Results

  • I added all the water to the starch and cooked it, but seems fine
  • It doesn't build up height but that is expected as well

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Recipe 7C - Extrudable Paper Paste

Use: paper clay, height, structure

Ingredients (10 g dry cellulose basis)

  • Cellulose (dry basis): 10 g
  • Cornstarch : 12 g
  • Water : 45–55 ml
  • Glycerine: 4 ml

Steps

  1. Slurry starch in 15–20 ml cold water.
  2. Heat until very thick custard.
  3. Fold hot starch into cellulose pulp.
  4. Add remaining water slowly while mixing.
  5. Add glycerine.
  6. Knead until cohesive.
  7. Rest 10 min.
  8. Extrude warm.

Results :

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References

Tutorials - Fabricademy Class Archive
Fabricademy 24-25 BIOPRINTING Tutorial on Vimeo

Biomaterial+Cookbook_compressed.pdf
Bioplastic Cook Book by Anastasia Pistofidou - Issuu
BIOPLASTIC-RECIPE.pdf
Tapioca_&FruitLeather_recipes_2022-23 - Tapioca&_FruitLeather_recipes_2022-23.pdf
The secrets of bioplastic by Anastasia Pistofidou - Issuu

Discover the Learning Paths - Shemakes Open Toolkit
3D Bioprinting - Shemakes Open Toolkit