What Is Glue Made Of?
Glue is a sticky liquid that can stick two or more things together. Glue can be made from plant or animal parts, or it can be made from oil-based chemicals.
The first glues may have been natural liquids that come out of trees when they are cut. Later people learned to make glue by boiling animal feet, cartilage or bones. Some very strong glue was first made from fish bones, rubber or milk.
Simple glue can be made at home by mixing rice or wheat flour and water. This glue will stick pieces of paper together. Many kinds of art can be made using glue. A collage is a work of art made by using glue to stick colored things onto paper.
Some glue can be used to keep water out of boats, buildings or vehicles. In this case the glue may be called caulk. Some man-made materials, including wood-like materials, are made using glues to bind together small pieces of material or powders.
There are different kinds of glues for different uses. The milky-white casein glue used to mend broken pottery and a loose joint of furniture, for example, is made from milk. The kind of glue called rubber cement is made from rubber. This kind of glue is good for bonding together paper, rubber or leather.
The mucilage glue on postage stamps and envelope flaps is made from plant starch. When it is moistened it becomes sticky. Plastic-glue, called epoxy, works well on almost all materials. It can form bonds that are stronger than the material it joins.