The common hinge has applications for a wide variety of environments from a kitchen cupboard to a door at the mall. Each type has standards and requirements to meet its application, which are specifications set by OSHA and other governmental agencies.
A particularly unusual application for hinges is for use in wet, damp, & corrosive conditions where the hinge is constantly exposed to harsh & moist atmospheric conditions. These specially designed hinges are referred to as marine hinges due to the fact that they are durable, resistant to the effects of salt water, and are anodized with a protective oxide layer.
Materials and equipment on a boat have to be able to maximize space while not being heavy, which applies to its hinges as well. For these reasons, marine hinges are manufactured using lightweight material, however they must still maintain their stability and strength to be able to endure harsh conditions. This is accomplished by coating them with a protective material to avoid damage from corrosion, wear, and rust, which can also be accomplished by anodization.
The specific grade of metal that is used for producing marine equipment includes all of the various types of metals from steel and stainless steel to aluminum and brass. The obvious first requirement of a marine metal is resistance to corrosion from constant exposure to water. To achieve this characteristic, metals are alloyed with other metals that are resistant to various forms of deterioration.
Common types of steel used for marine hinges are AH.36, DH36, and EH36, which are approved for shipbuilding and steel plating. To be accepted for marine use a metal must meet the standards of the American Bureau of Shipping (ABS), which produces a list of approved materials.
A unique form of hinge for marine use is the piano hinge that can be as long six feet in a variety of widths. It is so named for its use on concert pianos. They have a simple design of flat, straight, and symmetrical. Piano hinges for marine use are mostly found in situations that require strength, security, and durability such as lockers, instrument panels on boats, security doors, and tool cabinets.
Though piano hinges are commonly found in marine applications, other types of hinges include butt, glass door, concealed, and flush mounted. Butt hinges are less than five inches long and have rectangular pivoting plates. Glass door hinges are for frameless glass doors and come in a wide variety of hinge lengths, widths, and dimensions. As with butt and glass door hinges, concealed and flush mounted ones are produced to fit special situations but still have the same durability and strength as all hinges for marine use.
The versatility of hinges and the many types of materials they can be manufactured using allows them to be used in a variety of applications and industries. Protective coatings allow hinges to be made corrosion and rust resistant, making them a great choice for marine industry applications.