Stainless steel is known for its durability and visual appeal in all applications and environments. However in coastal environments, incorrect handling may cause it to stain or discolour.
This brown discolouration is known as tea staining and is often caused by salt deposited on the surface. Tea staining can be controlled and only affects the appearance of the material, which can be maintained with extra effort.
To avoid tea staining the environment must be taken into consideration. Tea staining mainly occurs within five kilometres of a beach or a few hundred metres from a sheltered bay.
One also needs to carefully select the correct grade of stainless steel. A higher grade is recommended, particularly for coastal environments, to avoid extensive tea staining or corrosion.
Another thing to consider is the finish of the stainless steel. Rough surface finishes promote tea staining. A smoother surface finish stays cleaner and doesn’t have grooves where contaminants can collect. Finishes can be made more corrosion resistant by passivating with acid to remove surface contaminants. Electropolishing can also be used to passivate the surface; this process also reduces roughness. An added benefit to electropolishing is that the surface becomes much brighter, thus enhancing appearance.
You can best maintain stainless steel hardware by washing it regularly, especially in coastal environments, removing any contaminates (i.e. salt) and thus minimising tea staining. It can be washed with soap or mild detergent and warm water followed by rinsing with clean cold water. To improve the appearance of the surface, dry after washing. Hydrochloric acid should never be used on stainless steel as it frosts the surface and causes pitting.