Galvanizing is where a metal (usually iron or steel) is coated with a layer of zinc to help protect it from the environment in which it is used or stored. The reaction for galvanization will only occur on clean surfaces and therefore in order to achieve a high-quality finish, the surface on the metal must be properly prepared. Any force of dirt, grim, grease or oil are considered to be contamination and will lead to flakiness or the finish peeling off easier than it should. A number of processes can be used to pre-treat the material such as shot blasting where the surface is cleaned or stripped using abrasives.
The protection offered by galvanization is heavily dependent upon the environment in which it is situated. Although galvanizing is generally regarded as giving a product a life of a number of decades, if the environmental impacts are kept to a minimum, it can last without rust in excess of 100 years.
However, if the galvanized item is situated on a cliff face in a coastal region with frequent and high levels of rainfall, this life will be significantly reduced. Supplementary treatments such as painting will help to extend the products life.