Stainless Steel Grade Selection
Stainless steel is a very popular choice for both inside and outside fittings and fixtures. If Stainless Steel is selected for a project close to the coast, it will require routine maintenance to prevent tea-staining corrosion. Regardless of the grade or finish we recommend our Action Clear Coat for all coastal stainless steel.
The most popular grades of Stainless Steel are 304 and 316 (marine grade) the differences between stainless steel grades are Chromium content and the addition of nickel and molybdenum to 316 grade. 316 generally has greater corrosion resistance than 304, however there is added expense for this grade.
Stainless Steel Finish Selection
“In aggressive environments, the smoother the surface, the better the corrosion resistance. A smoother surface is less susceptible to an accumulation of deposits, which may become focal points for localised corrosion.(ASSDA)”
It has been our experience that this statement by the Australian Stainless Steel Development Association is very true when building near the coast. We have found that the finish is as important as the grade of stainless steel used. Electropolishing is the process of highly polishing stainless steel, bringing chromium to the surface and smoothing the finish by 30%. This makes it more difficult for salt and impurities to attach. The Photo below demonstrates the importance of finish best.
This new home is about 500 metres from the beach.The handrail, uprights and clamps are the same 304 grade, however, only the handrail and clamps were electropolished. The uprights are satin finish. After only 4 weeks the uprights have corrosion whilst the handrail and clamps remain in good order. Action Corrosion used Rust Removal Cream to restore the upright and Action Clear Coat Xtreme to protect it from corrosion.
We always recommend having a highly polished finish on all external stainless steel proximate to the coast. We also recommend using Action Clear Coat to protect from corrosion on all stainless steel regardless of the grade and finish. This is particularly the case surrounding a pool where acid, chlorine and salt can quickly corrode spigots and fencing.