The galvanizing process has been used to protect metal (primarily steel) from corrosion for hundreds of years. The process basically involves cleaning the metal then dipping it into a vat of molten zinc. The multiple layers of zinc that form from this process prevent the underlying steel from corrosion. This has proven to be effective even in salt laden ocean front environments. The zinc does more than just coat the metal, it metallurgically bonds to it, actually becoming part of it. These layers of zinc dissolve at a very slow rate (acting as a sacrificial layer). This layer of zinc inhibits rust, providing decades of protection to the underlying iron work.
The level of corrosion protection is determined by Coating thickness. The thicker the coating the longer the life.
The geographical location where the ironwork will reside plays a crucial role in the longevity of the protection. Railing located in enclosed pool areas, at ocean front properties or in close proximity to salted roadways all require a thicker coating of zinc. It’s important to understand service environment when specifying a galvanized coating thickness.
Relatively low cost compared to using nonferrous (non rusting) metals like stainless steel or aluminum.
Low maintenance, coatings can last 25-50+ years.
Scratches or abrasions that compromise the coating are still protected by the surrounding zinc (galvanic cell).
Since during the hot dip process, the iron work is completely immersed in the molten zinc, the insides of tubing and interior crevasses of scroll ironwork get fully protected.
Can be painted or powder coated over the galvanized coating to enhance the beauty and add even more corrosion protection.
It is difficult to control drips and sags and other surface imperfections when hot dip galvanizing railings or other architectural metal work. The resulting surface is not as fine (even after powder coating) as it would be if powder coated alone.
Galvanized coatings are typically bright and shiny when freshly galvanized. Left unpainted, the finish will weather to a uniform dull gray appearance within a year.