Step one

1. Wash the mussel shells and remove remaining waste.

2. Cook the shells for 15 minutes.

3. Heat the shells for 1 hour on 200 degrees in the oven. This will make the shells more brittle .

4. Grind the shells into a powder.

5. Sieve the grinded shells to obtain a powder with particle size of maximal 75 micron meter.

Step two

1. Measure the desired amount of sugar (50% of total weight).

2. Measure the desired amount of water (50% of total weight).

3. Add sugar to the water and stir until a gel has formed.

Step three

1. Measure the desired amount of mussel shell powder

2. Add binder to the powder until the right ratio is met. The powder:binder ratio is 1:0,4

3. Stir until the ingredients are well mixed into a smooth paste

Step four

To print the paste, a syringe that is actuated by compressed air can be attached to the positioning system of an Ultimaker (we used  Ultimaker 2+). A digitally controlled pressure regulator has to be connected to the controller board of the Ultimaker, which makes it possible to control the extrusion pressure using pronterface 

Print settings:

Diameter syringe 22.5mm

Nozzle size 0.84mm

Pressure 0.22–0.34 bar

Print speed 5 mm/s

Layer height 1mm

Layer width 1.5mm

Build plate temperature 30 °C