Human hair for bow belly

[Tim Baker]

Unlike hide glue casein glue is fairly waterproof, and will adhere to somewhat oily surfaces. Strength tests I've done show it to be about half as strong as hide glue, which is strong enough for most purposes. Never done decent elasticity tests. The strongest casein glue I've made used washed and strained low-fat cottage cheese and 5% lime. Mix well, let set for an hour then use. Low pressure clamping if at all. 

[Tim Baker]

Some hide glue info:

The higher the gram strength of hide glue the quicker it gels, often too quickly. One solution is to keep the work, sinew and air at high temperature. Another is to dilute the glue.

Hide glue you make yourself, from sinew scraps or hide scrapings will typically yield about 180 gram strength glue, gels slower for longer working time, and is stronger than needed for about any imaginable need.

Gelatin glue is about 350 gram strength.
How to mix it:
http://www.frets.com/FretsPages/Luthier/TipsTricks/KitchenGlue/kitchenglue.html
Three times water weight to dry glue weight is difficult to mix. Six times is easier.

The lower the water content the quicker a sinewed back or such will dry.

Dry hide glue is about 1.3 specific gravity, twice as heavy as many bow woods.

Tensile strength up to 10,000-plus per square inch.

The lower the moisture content the higher the tensile strength, and vice versa

Can be stretched 5% to 10% of length.

[sleek]

Now I wonder about using a hybrid of casein and hife glue with blood mixed in for good neasure?