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 protect the underlying steel from corrosion. This has proven to be effective even in salt-laden oceanfront 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, essentially acting as sacrificial layers. The layers of zinc inhibit rust, providing decades of protection to the underlying ironwork.
The level of corrosion protection is determined by the coating’s thickness. The thicker the coating, the longer the life. Also, the geographical location where the ironwork will reside plays a crucial role in the longevity of the protection. Railings located in enclosed pool areas, at oceanfront properties, or in close proximity to salted roadways all require a thicker coating of zinc. It’s important to understand the surrounding environment when specifying a galvanized coating thickness.
Advantages of Hot Dipped Galvanized Railings:
- Using glavanized steel has a relatively low cost compared to using nonferrous (non-rusting) metals like stainless steel or aluminum.
- Hot-dip galvanized steel railings are low maintenance. Coatings can last 25-50+ years.
- They are durable and scratch resistant.
- Scratches or abrasions that compromise the coating are still protected by the surrounding zinc (galvanic cell).
- Since during the hot-dip process, the ironwork is completely immersed in the molten zinc, the insides of tubing and interior crevasses of scroll ironwork get fully protected.
- Galvanized steel post can be painted or powder coated over the galvanized coating to enhance the beauty and add even more corrosion protection.
Disadvantages of Hot Dipped Galvanized Railings:
- It is difficult to control drips and sags and other surface imperfections when hot-dip galvanizing railings or other architectural metalwork. The resulting surface is not as fine, even after powder coating, as it would be if powder coated alone.
- Galvanize dip tanks are limited in size which sometimes requires breaking up large sections of railing into smaller sections in order to fit them into the tank. This takes careful planning at the design stage, though it is possible.
Galvanized Steel Appearance:
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.