Glue Making

Glue Making

Organic glues begin with washing animal hides, bones, and other tissues to remove dirt and debris. The animal tissues are then soaked in water to begin softening them and start the process of releasing collagen.

After soaking, they are treated with lime and acid to facilitate the breakdown of tissue and release more collagen. The acid is later removed, and the collagen-and-water mixture is cooked down to produce a thick, gelatin-like substance that can be further purified and treated with other chemicals and ingredients as necessary to create the type of glue desired.

Process of manufacturing Glue:
Factories collect animal parts from slaughterhouses, tanneries, and meat packing companies, including remains such as scraps of hide or skin, tendons, bones, feet, ears, tails, fish heads, scales and skins.

All those parts are washed, dirt is removed, and everything is soaked so that parts are softened. Then, all hides and material are put through series of water baths that have more and more lime in them.

This makes material swell and break down. Then everything is rinsed in large washing machines, and lime is completely eliminated with the use of weak acids.

Animal material is then cooked in a boiling water (both open and closed pressurized containers are common), until the moment when collagen protein is released from the structure of the meat, and it breaks down to its glue form.

After several heat treatments (all with increased temperature), glue material is collected. Cold glue material (“glue liquid”) resembles jelly, but it cannot be used just yet.

Impurities have to be extracted. This can be performed both by mechanical methods (passing of heated glue fluid through mechanical filters, paper filters, or ground bone) and by chemicals such as alum and acids.

Finally, the exact color of the glue is imprinted by adding additives to the mix. Most common glue colors are blown, clear and white (zinc oxide produces white color, while phosphoric acid, alum and sulfurous acid are used for other colors).

After coloring, glue is still in very weak liquid that needs to be hardened. Extraction of the water from the mix is done in several ways – Drying, chilling or dropped as beads into non-water bearing liquor that slowly extract water from the glue.

Entire process of glue manufacture has to be monitored very closely, with sensors controlling temperatures, timings, extraction of impurities, safety measures, decontamination, and more.

Bone glues have slightly different process of production. Bones are degreased in solvents, and then mixed with hydrochloric acid that removes large amount of minerals and calcium phosphate, leaving only collagen behind.

After removal of acid from collagen, resulting glue liquid is colored and dried. Packaging is done with specialized machines. Glues made from animal parts don’t have long shelf life, with some having as little as 1 year.

Wishing you all the best,