Brooklyn Tool & Craft Hide Glue is a natural animal protein adhesive. It is supplied in the form of dry granules that are mixed with water and heated to form an excellent adhesive for lutherie, marquetry, veneering and cabinetry. Gram strength is a measure of hide glue strength and open time. The 315-gram strength is considered optimal for lutherie work and small repairs. It is the strongest of the three BT&C glues with the shortest open time. All BT&C glues are supplied as dry granules which are mixed with water, then heated to a temperature of about 140-145 and used hot. A double boiler is sufficient to heat the glue as long as the correct temperature can be monitored and held, or you can purchase a Hold Heat Glue Pot which holds the correct temperature automatically.