Older than the industry. Casein glue and casein paint are ancient; the idea that the same protein could be a solid material in its own right is late nineteenth century. In 1893 the French chemist Auguste Trillat found that soaking casein in formaldehyde made it insoluble. In 1897 in Germany, Adolf Spitteler and Wilhelm Krische patented a casein material — the origin story attached to it is that the work began with a commission for a washable white schoolboard rather than for a plastic at all.

Galalith. The product was named from the Greek for milk and stone. It was hard, took brilliant colours, could be polished to a deep shine, and did not burn easily — a serious advantage over celluloid, which did. It became the button material of the first half of the twentieth century, and also went into buckles, combs, knitting needles, fountain pens and costume jewellery.

Why it is machined, not moulded. Hardened casein cannot be melted and injected like a thermoplastic. It was made as sheet, rod, tube and button blanks, hardened, then cut, turned and polished to shape. The hardening is slow because the formaldehyde has to diffuse right through the piece: thin sheet takes days, and a block around 25 mm thick can take up to a year of immersion.

What replaced it. Petrochemical plastics after the Second World War were cheaper, faster to mould and genuinely waterproof, and casein plastic collapsed into a niche. It has never entirely gone: it is made from a renewable feedstock and is biodegradable, which is why casein materials keep reappearing in bioplastics research.

What you actually made. The same protein, coagulated the same way, kneaded and dried the same way. What you skipped is the formaldehyde bath — the step that turns a water-sensitive protein solid into a material you could sew onto a shirt and wash. It is documented in the companion blueprint for adults working with proper extraction; it does not belong in a kitchen.

Plastic Making

Blueprints (2)

Galalith

Milk Plastic