MycoCode: Development of an Extrudable Paste for 3D Printing Mycelium-Bound Composites

Additive manufacturing of sustainable and biodegradable materials offers an alternative fabrication paradigm to current composites used in architecture, based on the growth of materials rather than on extraction. This research investigates the extrusion of a mycelial-hemp and clay mix without additional additives and thoroughly evaluates the steps leading to it. The analysis entails four major steps: manual material investigation to figure out the finest ratio between clay and hemp shives for smooth extrudability, understanding hardware and software determinants that impact the resultant printed form, preparation of the material for 3D printing under sterile conditions and printing the Mycelium-clay mix varying properties analyzing the emergent characteristics of the material. Therefore, the research explores the possible combination ratios of a clay substrate with the addition of hemp shives inoculated with Pleurotus Ostreatus, without using any additional additives to test the paste’s extrudability properties. The research successfully achieved a balanced ratio between mycelium, hemp, clay, and water when the relative percentage of clay and hemp shives were kept at 85–15%, respectively. The investigation also helped deduce that 3D extrusion printing with the Delta WASP 40,100 Clay Printer, with a nozzle diameter of 9 mm, is most optimal when the layer height is one-third of the nozzle diameter and the Extrusion (E) Value and Feed rate (F) is kept constant throughout the printing, in our case at 30 mm and 1500 mm/min, respectively.