Animal Glue - Wikipedia

Early uses

Animal glue has existed since ancient times, although its usage was not widespread. Glue deriving from horse tooth can be dated back nearly 6000 years, but no written records from these times can prove that they were fully or extensively used.[5]

The first known written procedures of making animal glue were written about 2000 BC. Between 1500 and 1000 BC, it was used for wood furnishings and mural paintings, found even on the caskets of Egyptian pharaohs.[6] Evidence is in the form of stone carvings depicting glue preparation and use, primarily used for the pharaoh's tomb furniture.[7] Egyptian records tell that animal glue would be made by melting it over a fire and then applied with a brush.[8]

Ancient Greeks and Romans later used animal and fish glue to develop veneering and marquetry, the bonding of thin sections or layers of wood.[6] Animal glue, known as taurokolla (ταυρόκολλα) in Greek and gluten taurinum in Latin, were made from the skins of bulls in antiquity.[9] Broken pottery might also be repaired with the use of animal glues, filling the cracks to hide imperfections.[10]

About 906–618 BC, fish, ox horns and stag horns were used to produce adhesives and binders for pigments in China.[11] Animal glues were employed as binders in paint media during the Tang dynasty. They were similarly used on the Terracotta Army figures.[12] Records indicate that one of the essential components of lampblack ink was proteinaceous glue. Ox glue and stag-horn glues bound particles of pigments together, acting as a preservative by forming a film over the surface as the ink dried.[9] The Chinese, such as Kao Gong Ji, also researched glue for medicinal purposes.[13]

Reemergence

The use of animal glue, as well as some other types of glues, largely vanished in Europe after the decline of the Western Roman Empire until the 16th to 18th centuries, when wooden furniture started to surge as a major craft.[6][dubious – discuss][unreliable source?] During the medieval ages, fish glue remained a source for painting and illuminating manuscripts.[14] Since the 16th century, hide glue has been used in the construction of violins.[7]

Native Americans used hoof glue primarily as a binder and as a water-resistant coating by boiling it down from leftover animal parts and applying it to exposed surfaces. They occasionally used hide glue as paint to achieve patterns after applying pigments and tanning to hides.[15] Hoof glue would be used for purposes aside from hides, such as a hair preservative. The Assiniboine preferred longer hair, so they would plaster the strands with a mixture of red earth and hoof glue.[16] It was also used to bind feathers and equipment together.[17]

Glue industries

The first commercial glue factory opened in Holland circa 1700, manufacturing animal glue from hides.[6] The United States' first glue factory opened in 1899, established by the Milwaukee Tanning Industry.[5] The L.D. Davis company thrived producing animal glue during the Great Depression after shifting its focus from stenciling, selling to local box makers and other users. L.D. Davis' animal glue formula for bookbinding remains in production.[18] During the 18th and 19th centuries, ranchers disposed of old animals – horses in particular – to glue factories. The advent of synthetic adhesives heralded the collapse of the animal glue industry.

Modern uses

Today, animal glues are sparsely industrialized, but still used for making and restoring violin family instruments, paintings, illuminated parchment manuscripts, and other artifacts.[9] Gelatin, a form of animal glue, is found in many contemporary products, such as gelatin desserts, marshmallows, pharmaceutical capsules,[19] and photographic film and is used to reinforce sinew wrappings, wood, leather, bark and paper. Hide glue is also preferred by many luthiers over synthetic glues for its reversibility, creep-resistance and tendency to pull joints closed as it cures.

This adhesive is mostly used as glue, sizing, or varnish, although it is not as frequently used as other adhesives because it is water-soluble. Other aspects, such as difficulty of storage in a wet state, requirement for fresh raw materials (the animal skin cannot be rotten or grease-burned), make this product more difficult to obtain and use. Factories now produce other forms of adhesives, as the process for animal glue is complex.[20] Animal glues will also darken with age and shrink as they dry, giving them the potential to harm wood, paper, or works of art. Too much handling and too many changes in temperature or humidity could cause further harm.[10] Some companies, such as those in Canada, still produce animal, hide and hoof glues from horses. Recently, animal glue has been replaced by other adhesives and plastics, but remains popular for restoration.