Milk

One method to make glue is from milk. You need:

skim milk
vinegar
non-metallic pan (enameled o.k.)
baking soda

Heat a pint (half a liter) of skim milk and six tablespoons (90 ml) of vinegar slowly, stirring constantly. When it begins to curdle, remove from heat. Continue stirring until the curdling stops. Let sit until the curds have all settled to the bottom. Either strain the curds or pour off the liquid until they are dry. Add 1/4 cup (60 ml) of water and a tablespoon (15 ml) of baking soda (borax also will work). When the bubbling stops, you have made glue.

What is happening in this process is that the milk solids are being separated from the liquid. These solids, the curds, dry to form a hard plastic-like substance called casein, which also acts as an adhesive. The vinegar functions to curdle the solids so that they can be separated, and the soda neutralizes any acid that is left.

Offered by Steve.

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

Curdled Milk Glue

Casein glue can be made from curdled skim milk or low fat cottage cheese. They can be used on wood with up to 15% moisture content as well as oily woods. Commercial casein glues contain dried curd casein, lime, sodium salts and fungicide. However, insects, mice, mold and bacteria also love casein glues.

Milk becomes somewhat water resistant after curdling. When dry, it loses considerable strength after some time in water, but does not dissolve. The curds do not make a smooth textured glue, but by adding lime, about 5% per volume, the curds break down to a smooth consistency. Lime also makes curd glue fairly waterproof.

 

Cottage Cheese Glue

Wash and strain the cottage cheese until the curds are clean. Drain for fifteen minutes - removing as much free water as possible as it yields thicker, stronger glue. Add 5% lime per volume, stir well and let set one hour, stirring occasionally. Strain and use. Apply liberally, no sizing needed. Apply pressure to hold work in place.