Frequently Asked Questions

How Long Will Galvanized Steel Last?

Hot-dip galvanized steel will last very well in most environments. It is not uncommon for galvanized steel to last more than 70 years under certain conditions. To get a good idea of how long your project will last. Click here to see the zinc millennium map.

Does the galvanized steel coating of zinc resist abrasion?

The three inter metallic layers that form during the galvanizing process are all harder than the substrate steel and have excellent abrasion resistance.

What Is "White Rust" And How Can It Be Prevented?

"White Rust" or Wet Storage Stain is formed because, zinc on newly galvanized steel is very reactive and quickly forms zinc oxide and zinc hydroxide corrosion products that go on to become the stable zinc carbonate. When galvanized steel is stacked damp or stored in wet boxes or shrink wrapped with no free flowing air, the zinc forms excessive layers of zinc hydroxide, otherwise known as wet storage stain. Most wet storage stain can be easily removed with a nylon brush. To prevent wet storage stain, store galvanized steel indoors and in such a way to allow free flowing air between each galvanized item.

Why Does The Appearances Of The Coating Sometimes Differ From Job To Job And And Will Any Difference Affect How Long It Lasts?

The chemistry of the steel is the main influence on coating thickness and appearance. Steel produced by the steel companies has a wide variety of chemistries, thus the different coating appearances. The galvanizer may also add several different additives to their galvanizing bath to enhance the coating appearance by making it shiny, spangled or minimizing the reactivity of certain steel chemistries. The appearance of the coating does not change the corrosion protection of the zinc coating.

Isn&Lsquo;T Galvanizing More Expensive Than Paint?

Depending on the product and condition of the steel surface, the initial cost of galvanizing is very often less than paint. However when the lifetime cost of a project is considered, the life cycle cost of galvanizing i.e. the cost per year to maintain, is almost always less than a paint system. Paint systems require maintenance or reapplication at various intervals over their lifetime. These costs can be considerable, making the decision to paint a costly one in the long run.

What is the Difference Between Hot-Dip Glavanized Fasteners and Zinc-Plated Fasteners?

Hot-dip fasteners generally have about 10 times as much zinc on the surface and are suitable for use in all exterior and interior applications. Zinc-plated fasteners will provide a disappointing performance if used outside, especially when used to connect hotdip galvanized structural steel.

Why Do I Have To Include Venting & Drainage Holes Into A Fabrication?

The main reason for these holes is to allow otherwise trapped air and gases to escape and to allow cleaning chemicals and molten zinc metal to flow throughout the fabrication, and then back into the tank. Because of the temperatures involved in the galvanizing process there is a significant risk of explosion when any trapped liquid is rapidly heated in the galvanizing bath.

What Is "Cold" Galvanizing?

There is no such thing as cold galvanizing. The term is often used in reference to painting with zinc-rich paint. Galvanizing requires heat in order to produce the metallurgical bond between coating and steel that gives Galvanizing its long life & hard wearing characteristics.

Will The Coating Be Badly Damaged After Galvanizing?

Small areas of the galvanized coating may be damaged by cubbing of welding. The galvanized coating has excellent resistance to rough treatment, however, small areas of damage can occur, occassionly in transport and erection.

Due to the sacrificial action of zinc, small localised flaws do not reduce protection.
It is often aesthetically desirable to renew the coating over these small areas. Adequate corrison resistance can be achieved using several renovation methods. Techniques according to British Standard should be used.
Please contact us to discuss further.

What Preparation Work Will I Have To Carry Out To The Steel Prior To Galvanizing?

The galvanizing reaction will only occur on a relatively clean surface.

As with other coatings, the quality of the coating is often dependent on the preparation of the area.
The steel is dipped into Hydro-chloric Acid prior to being galzanized, which removes any rust or mill scale. However, welding slag, paint and heavy grease is not removed by this process and will need to be removed by other methods.