Eggstone

diy

materials

Student

María Eugenia González de Quevedo

Lecturer/s

Aart van Bezooijen

Course topic/s

Design and Materials: Do-It-Yourself Materials

Course/s

MA Practice Based Course

Year

2022

semester

WHAT IS EGGSTONE

This clay-like biomaterial is made of eggshells, water, gelatin, and glycerine. It works as an alternative to limestone while repurposing organic waste. It can be extruded, cast into a mold, or dried as a thin and organic-shaped stiff surface, as well as engraved.

Do we fully appreciate the value of calcium?

Calcium is the fifth most abundant element on Earth and the world’s building block. Most of us are familiar with the idea that our bodies need calcium “to make our bones strong”. In fact, many organisms use calcium to build the structures that house and support them – skeletons, eggshells, mollusk shells, coral reefs, and the exoskeletons of krill and other marine organisms. And calcium is also the key ingredient in man’s most important structural material – cement. Its main component, limestone, contains above 80% of calcium carbonate, a common form of calcium, which stability makes it a durable construction material.

When experimenting with my organic food waste, I realized that the hard, outer covering of an egg offers possibilities as a substitute for limestone and other building materials, due to its high content in calcium carbonate. The rest is made up of protein and other minerals. The food industry makes this material easily available, and its potential should be explored.

As a further development, it would be interesting to obtain an eggshell-based material that can be 3D printed. At the moment, this is not possible because the mixture takes too long to dry.

HOW TO MAKE IT

Ingredients

80 g water

12 g gelatin

30 ml eggshell

10 g glycerin

Tools

Blender or coffee grinder

Scale

Pot

Stove

Spoon (to stir)

Mould (silicone, non-stick material, no cardboard), oven paper or non-stick material

Process

1) blend fully dried shells until they become a thin powder

2) dissolve the gelatin in hot water, then add the rest of ingredients (glycerin and eggshell powder)

3) heat the mixture on low power in a pot while steady stirring, until the mixture becomes thicker

4) cast mixture into a silicone/coated paper mold or apply to a non-stick surface

5) let it dry at room temperature

Difficulty: 1

Duration: 30 minutes for preparing and up to 15 days to have a completely dry product.

Gallery

The two samples at the left are created with the same recipe: eggshell, water, gelatin, and glycerin. In turn, the sample at the right contains eggshell, potato starch, water, glycerin, and vinegar. This image shows the rigidity and strength that can be obtained with an eggshell-based biomaterial, as well as its white color and soft texture. It can be cast into a mold or dried into a thin surface.

This image shows how the eggshell powder precipitates to the bottom of the mold in which it is cast (it is upside down) and separates from the gelatin creating an interesting volume. This experimentation leads me to believe that the amount of gelatine could be reduced. However, this double feature (ductile/stiff, plastic/stone) could be useful for certain products.

Image of the process. The first step is to blend the eggshells to obtain a thin white powder. I used a Black and Decker coffee grinder.

It is important to ensure that the eggshells are well dried before starting the process to avoid the development of mold in the material. However, the fact that it takes so long to dry makes it easy to obtain mold anyway, as I did.

This sample contains 8 gr of eggshell, 3 drops of red food coloring red, 18 gr of water, and 9 gr of oil.

The final result breaks when dry. This failure led me to use glycerine and pectin as "glue" instead.

I tried many different combinations of ingredients, and I always obtained a strong and stiff result, even when dried into a thin layer.