Sinew

Information provided from The Traditional Bowyer's Bible, Bois d'arc press:

Made from leg or backstrap sinews, or from sinew scraps.

• Place sinew stock in a large pot, with lid and cover with water.
• Simmer at approx. 170 degrees for about 24 hours or more, stirring occasionally.
• Towards the end remove lid and let the mix evaporate down to a light syrup - just barely thicker than water.

During the last hour of simmering occasionally scoop off any fat, foam and impurities. Bring the mix to a light rolling boil for the last ten minutes or so. This will help bring the impurities up to the surface. So keep the temperature high enough to prevent a skin forming on the surface. The strongest part of the glue skins up first so you'll end up wasting the best part of the glue if you allow a skin to form.

The longer glue cooks, the darker and weaker it becomes so the first pouring, after ten hours or so of simmering, is the strongest glue. Continued simmering of the remains for a further 24hours, or until the stock mass no longer reduces, results in a slightly less strong glue, but still excellent. If you're in a hurry don't bother simmering.

• Bring the sinew to full boil right away and hold it there for two to three hours.
• Strain off impurities as above.
• Let the mix boil down to a light syrup and that's it.
• The quick glue will be virtually as strong as slow glue.
• Pour the light syrup through a fine-weave cloth to filter (optional). Then pour into wide trays or plates to allow them to jell. Pour 1/2" deep or less.

At this stage bacteria can convert the glue to a smelly gruel before it has time to dry. To speed up drying cut the jell into 1/2" to 1/4" cubes, sprinkle onto a clean surface to dry. Wind speeds up the process, but keep cool and out of direct sunlight to prevent melting. When hard and dry, store out of reach of insects and rodents. If kept dry its shelf life is unlimited. If the mix is watery it may not jell rigidly enough to hold its shape for cutting. Only freezing will allow this mix to set.

To Use

• Soak the shrunken granules in sufficient cold water to cover.
• Wait a few hours, until that are plump and jelly-like throughout.
• Heat to 160 degrees and stir until uniform, then let cool to a working temperature of 110 to 140 degrees, depending on the materials to be glued. If necessary thin to a medium-light syrup. The glue pot should be kept below 140 degrees. At 175 degrees animal glues loose over 2% of its strength per hour. Successive re-melting also weakens animal glue.