Casein glues are splendid in woodworking, making cardboard articles, and when the composition is varied somewhat, make excellent cements for china and metals. Casein is made from the curd of soured milk after removal of the fat, and is put on the market in the form of a dry powder.

To make the glue, soak the casein powder two hours in an equal weight of hot water. To this gummy mass add about one-seventh the weight of the casein in borax which has been dissolved in very little hot water. Stir until all is dissolved after mixing borax and casein. This can be thinned with water to suit and is a good glue, but it can be made more adhesive by the addition of a little sodium arsenate. Any alkali, such as soda or ammonia, could be substituted for the borax.

To make a china cement, lime or water glass should be substituted for the borax. Addition of burnt magnesia increases the speed of hardening.

A Casein Glue 490