Industrial gelatin

This is a technical gradeof gelatin made in Egypt of cow skin. It is ideal for use in glue.

Gelatin glue is graded and sold by its BloomValue or Bloom strength. Bloom valueis a measurement of the strength of a gel formed by a 12.5% solution of theglue that has been kept in a constant temperature bath at 10 C for 18 hours. Adevice called a Texture Analyzer or Bloom gelomater is then used to measure theweight in grams required to depress a standard plunger 4 millimeters into the gel.If this procedure requires 200 grams, then the glue is a 200-bloom value glue.Glue is also tested for its viscosity at this same 

12.5% concentration. A standard viscosity range is associated with each bloomlevel.

Source and Properties
Animal glues are adhesives that are highmolecular weight polymers in organic colloid form from hydrolyzed collagenfound in animal hides, connective tissues and bones. Glue contains two groupsof proteins: chondrin, which accounts for its adhesive strength, and gluten,which contributes jelling strength. Animal glue is derived from the simplehydrolysis of collagen, which is the principle protein constituent of animalhide, connective tissue and bones.

Hide and bone glues make up the two majortypes of animal glue. Hide glue yields a fairly neutral pH in solution, usuallyin the range of 6.5 to 7.4, although wider variations are possible. Bone glueis generally acidic, having pH values of 5.8 to 6.3. A glue having a highacidity absorbs less water and tends to set more slowly than a glue having lowacidity.

Animal glue is soluble only in water andinsoluble in oils, greases, alcohols and other organic solvents. When placed incold water, the glue absorbs water and swells to form a gel. When heated theglue dissolves to form a solution. When the solution is cooled the glue onceagain forms an elastic gel. This property is thermally reversible and uponapplication of heat the gel liquefies. The gelling or melting point of ananimal glue solution can vary from below room temperature to over 60 C,depending upon the grade, concentration and presence of modifiers in the glue.


Specifications
Bloom: 100 - 450 grams
The bloom measurement refers to the elasticityof a gelatinous mass. The higher the number the greater the elasticity.

Viscosity: 50 - 160 m.p seconds
The m.p. seconds is a measurement of viscositywhich is measured by the flow velocity of the glue solution through a funnel.


Use
Always make the minimum concentrationrequired; as a guide, a set jelly should be somewhere between firm gel andjelly. For a canvas or panel size, try 50 grams of gelatin for every liter ofwater. For distemper paints, 80 to 100 grams for every liter. As an adhesive,check the consistency by dipping a piece of wood into the glue pot. If the glueruns off smoothly, you've got it right. If it is too thick, add a little