is an adhesive
that can be prepared with normal household products. Homemade glue experiments are often part of the educational curriculum.
Most basic homemade glues use the milk protein casein that is precepitated after denatured with acetic acid from vinegar, forming curds while the supernatant is called whey.
When neutralizing the curds with a base such as sodium bicarbonate (baking soda), the casein tends to unclump and become a thicker plastic-like substance.
In the late 1800s in Switzerland, casein was first used as a wood glue. Today, it is seen to be used to glue grocery sacks.
A glue can be made from starch found in wheat flour or corn starch.
An animal glue can be prepared from gelatin.