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The Best Way To Protect Steel From Corrosion

September 18, 2019


Corrosion occurs when a metal is exposed to natural electrolytes, such as salt, oxygen, and water. This exposure forms oxides on the surface of the metal piece, which causes corrosion. (The oxides occasionally combine with sulfides and carbonates.)

The entire natural process of corrosion reverses a metal back to its original state of ore, making it weaker and more susceptible to damage from the natural elements and overuse.

Most metals have the innate ability to corrode, especially stainless and carbon steel. Because most commercial buildings are made of steel and five common methods of corrosion exist, it’s important that your building is protected at all times.

Here’s how to protect steel from corrosion, according to the painting and wallcovering experts at Cochran & Mann in Frederick, Maryland:

Zinc Coating

Zinc is a natural chemical element with an innate resistance to corrosion, making it suitable for all steel pieces. It forms “dense, adherent corrosion byproducts” and acts as a barrier between the iron or steel piece and the environment, according to the American Galvanizer’s Association (AGA).

The most popular zinc coating methods are sheet metal fabrication techniques, including batch or continuous sheet hot-dip galvanizing, mechanical or zinc plating, and electrogalvanizing. However, painting techniques, such as zinc-rich painting (often mistaken as cold galvanizing) and metalizing/zinc spraying, also provide protection against corrosion.

For more about zinc-rich painting, such as coating characteristics and paint application, visit this article by the AGA.

Polyurethane Top Coat

Polyurethane top coat (also known as a urethane finish or sealant and epoxy coating) is the most popular corrosion prevention method. It's an especially reliable and economical choice for corrosion prevention in commercial buildings that use stainless and carbon steel. This high quality top coat is an all-weather sealant that protects against corrosion as well as the following:

  • Scratches
  • Impact
  • Abrasion
  • Chemical exposure
  • Natural elements, including ultraviolet (UV) rays and snow

Aside from corrosion prevention, polyurethane top coat provides a pleasant, durable appearance to finished metal.

“Urethane coating presents a thin film, high-gloss finish with exceptional weathering performance characteristics,” according to Cor-Pro Systems, a corrosion protection company in Houston.

For more information about polyurethane top coat, visit Cochran & Mann's 4 Surfaces That Benefit From Urethane Coatings.

Powder Coat

A direct alternative to paint, powder can also coat steel to protect from corrosion. Factory professionals either spray electrostatically charged powder onto the steel piece in a booth or lower the piece into a bed of fluidized powder.

Once coated in powder, the steel piece is cured in an oven that’s heated between 375 to 400 degrees Fahrenheit. The powder flows over the piece, gels into form, and dries with a firm, durable finish.

Powder coatings can incorporate different colors and various formulations to meet specific commercial project needs, such as additional protection from abrasion, chemical exposure, or UV rays. Unlike the popular option of polyurethane paint for steel, a regularly maintained powder coating doesn’t crack, chip, flake, or peel.

Corrosion prevention is necessary to sustain the aesthetic look of a commercial exterior project that uses steel. It’s also necessary to provide a sealant for extreme weather conditions, especially rain.

Zinc-rich painting, polyurethane or epoxy top coat, and powder coating are all corrosion prevention methods that a commercial painting company can provide for small and large businesses that use stainless or carbon steel.

For more information on corrosion, prevention methods, and duplex systems (using more than one corrosion prevention method for the ultimate protection), click on the button below to download Cochran & Mann’s Corrosion Prevention Methods Guide:

Download The Corrosion Prevention Methods Guide

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