The Facts

• Joint compound can be made of water, limestone, ethylene-vinyl acetate polymer, expanded perlite and other chemicals. The whole idea behind the compound is to create a smooth surface that bonds with drywall paper and seals the small cracks that occur between two sections of the drywall when it is hung. It comes in several varieties for different applications, including heavy and lightweight.
  
  

Identification

• Joint compound comes in several varieties for different applications. The most popular is lightweight ready mix joint compound, which can be considered as all-purpose and is suitable to use in the home. It is premixed, very soft and feels like clay. It smells a little bit like moth balls and wet cement and is cold to the touch. Other varieties include heavy duty mixtures and water soluble compounds that can be mixed on site.
  
  

Features

• Joint compound is very smooth so it takes little effort to apply it in large quantities. It can be worked into very small cracks and holes and fills in the drywall seam to create a very even, false surface over the seam. Though it is smooth, it will dry into a very hard shell. If you tap a dry section though, you will notice it is not as hard as regular wall plaster.
  
  

Function

• Joint compound creates a very true and flat surface. It can be carried on site and applied right from the bucket with no mixing required. It is designed to finish your wall, just like plaster, but it fits between the two drywall slots. Drywall sheets taper at the ends to accommodate the joint compound so there is no bulge in the wall. Many people also use it to fill in small nail holes in their walls, but this is not the proper usage. Drywall joint compound is best used as a plaster. Since it is so smooth, it will not fill a hole properly, but it will create a smooth skin over it. Spackle is a better choice for filling in holes.
  
  

History of

• Joint compound has been used in North American for several decades. Prior to its wide-spread use, other types of plasters were used. In colonial times and as recently as 1960, slat boarding, or small thin strips of wood, were applied to walls, then plaster was slathered on top of them with a large trowel and left to dry. Similar plasters have been in use for centuries for building walls and other decorative applications. Since the ancient times plasters have been used to cast molds, create vases and finish walls.