BIOFOAM (surface, solid)
Tactility & sound impression
Description
A thin, textured sheet, and half domes of foamy, flexible bioplastic. Gelatine-based.
Physical form
Surfaces, Solids
Fabrication time
Preparation time: 1 Hour
Processing time: 5 days
Need attention: after 3 days to demold, and keep pressed. After another 2 days to take them out of the press and air dry/store.
Final form achieved after: 1 week
Ingredients
-
Gelatine powder - 12 gr
- Functions as the polymeer (makes it hard)
-
Glycerine - 12 gr
- Functions as plasticizer that bonds with the gelatine (makes it flexible)
-
Water - 150 ml/gr
- To dissolve and mix the polymeer and plasticizer
-
Dishwashing soap (organic) - 1 tsp
- Is the expanding agent that makes the mixture foamy
Tools
- Cooker or stove (optional: temperature controlled)
- Pot
- Scale
- Spoons
- Whisk
- Lego sheet (or other textured surface)
- Egg holders (or other mold), these came with my fridge
Yield before processing/drying/curing
Approx. 150 ml
Method
-
Preparation
- Weigh your ingredients
- Prepare the molds you wish to use
-
Mixing and dissolving the ingredients
- bring the water to the boil
- optional: add natural dye if you wish to use color
- add the glycerine
- add the gelatine
- keep the temperature below 80 degrees celcius while stirring gently, until the gelatine is dissolved
-
Cooking the ingredients, creating foam
- Simmer and slowly stir the mixture between 60-80 degrees celcius for 20 minutes or until it's thick like a syrup or honey, then add in the soap
- Whisk vigorously to create foam bubbles and simmer for another 2-5 minutes until the mixture thickens
- Stir slowly to let the bigger bubbles pop until you have a foam with small bubbles
-
Casting the foam
- Cast onto the lego sheet (or other textured sheet) and spread out if necessary. Cast in the center of the sheet and allow the material to spread itself, keeping the pot still for even results. Or cast into the cups.
- The material will shrink a lot so make the layer thicker than you want the end result to be.
- Let it dry for 48-72 hours at least before releasing
Drying/curing/growth process
Peel it off the mold after 48-72 hours. The foam should not feel cold to the touch, then it's still drying. Pinch off the more fragile sides first to create some grip. Then pull it off carefully, pulling upwards.
- Mold depth: 3 mm
- Shrinkage thickness: 30-50 %
- Shrinkage width/length: 0-10 %
Shrinkage and deformation control
This recipe results in a somewhat flexible material so it's ok to cast onto a rigid mold, the flexibility will allow you to release it.
The lego texture keeps the foam in place and will help reduce shrinkage on width and length.
Waiting too long to release from the mold can result in tearing. The foam gets a bit more brittle and thin as it dries. Releasing it too early might leave finger prints and presses in the foam as its still too soft.
Curing agents and release agents
None.
Minimum wait time before releasing from mold
2 days
Post-processing
The sides will curl upwards upon further drying. I cut off the thinner edges (they curl more) to create an even sheet.
You can keep the sheet pressed at intervals of a day or so between kitchen paper and a stack of books to keep it flat if it curls up. Try to air it out too to prevent mold growth.
Store flat in a dry and ventilated room.
Further research needed on drying/curing/growth?
Yes. Casting solids or smooth surface might require a different process to prevent deformation.
Process
Mixing the ingredients at 80 degrees, Loes Bogers, 2020
The gelatin is dissolved and thick, ready for the soap to go in, Loes Bogers, 2020
Whisking the liquid vigourously to create small bubbles, Loes Bogers, 2020