Posted on: 11 August 2015
Iron work fences can last decades, which lets contractors who install wrought iron fences offer a lifetime warranty on their work. According to a report in Fastener Technology International, hot-dip galvanized metals will hold up for 50 to 80 years. If you're a contractor who builds iron work fences and you want to set your company apart by offering a lifetime warranty on your fences, make sure you use hot-dipped galvanized iron. Cold-galvanized iron won't withstand the elements as well, and using it could leave your company with a bunch of warranty claims to honor.
Iron Work Rusts When It Gets Wet
When iron work is left exposed to the elements, it quickly corrodes. Fred Sense, a faculty member at Frostburg State University details the process: Iron (Fe) and water (H2O) undergo chemical reactions that create iron III hydroxide (Fe(OH)3), which dries to form iron III oxide (Fe2O3). Iron III oxide is commonly called rust.
As this explanation shows, water is the agent that creates rust. Acids in acid rain and smog can accelerate the process, but the primary agent of rust is oxygen found in water.
Galvanization Protects Iron from Water
Galvaniztion prevents iron from rusting by creating a protective barrier between the iron work and elements. A zinc coating is placed over the iron, so it doesn't come into contact with water. Since the iron and oxygen in water never come into contact with each other, the chemical processes that create rust never get started.
When coating iron with zinc, it's important to coat all of the iron evenly. Thinly coated areas won't provide as much protection as places where there is a thick coating. Even worse, if any iron is left uncoated, it will rust and undermine the effectiveness of the galvanization.
Cold Galvanization Is Inexpensive but Inadequate
Many contractors who install iron work fences use cold-galvanized iron, because it's cheaper than hot-dip galvanized iron. In fact, you can save money by purchasing ungalvanized iron and cold-galvanizing it yourself. Cold galvanization uses a zinc-laden paint that's applied at ambient temperatures to protect the iron from rust. The paint can be purchased in a spray can and applied on-site.
Cold galvanization, however, will eventually wear down. First, it's impossible to get make sure the zinc-laden paint is applied evenly, so some areas of your iron work will be less protected than others. Second, if the paint is scratched, it may begin to peel and let water reach the iron underneath.
Finally, you won't be able to galvanize the inside of any hollow iron piece that you use. For example, if you have hollow railing pieces that are 1 inch wide and 6 feet long, you won't be able to coat their interior with the zinc-laden paint. If water seeps inside these pieces, it will corrode them from the inside.
Therefore, even though cold-galvanized iron may be inexpensive, you shouldn't use it if you offer customers lifetime warranties on your fences. Eventually, the zinc laden paint will fail, and you'll be faced with warranty claims.
Hot-Dip Galvanization Lasts 50 to 80 Years
In contrast, hot-dip galvanization, as Voigt & Schweitzer explain, evenly coat all pieces with zinc. In hot-dip galvanization, each piece is submerged in a zinc bath, so even the inside of hollow pieces are coated with the protective zinc galvanization. According to a report in Fastener Technology International, hot-dip galvanization can protect, which contains iron, from rust for 50 to 80 years. It will protect plain iron for a similar length of time -- which is long enough that you can offer a lifetime warranty on your fences.
Because hot-dip galvanization is a more involved process than cold galvanization, hot-dip galvanized iron typically costs more than cold-galvanized or ungalvanized iron. If you are building your iron work business by offering customers lifetime warranties, though, it's worth paying more for hot-dip galvanized iron. Your upfront costs may be higher, but you'll have fewer warranty claims in the future, because the galvanizing method will protect your iron work from rust for decades.Share