Knowledge centre ITW Spraytec Expert

Cold galvanizing provides effective corrosion protection

What is the principle of cold galvanizing?

Cold galvanizing, also known as cold zinc plating, allows for the touch-up and repair of damaged hot-dip galvanized surfaces. While less durable than hot-dip galvanizing, cold galvanizing offers effective corrosion protection.

It can be packaged in a can, applied with a brush or paintbrush, or in an aerosol can for a better finish.
Cold galvanizing is a process that involves applying a coating containing zinc. The zinc acts through electrochemical protection, while the resins, often synthetic, form a physical barrier resistant to external elements.

What is the corrosion resistance of cold galvanizing?
Corrosion resistance is assessed, in particular, using the salt spray test ( ASTM B117). This is a standardized evaluation that measures the corrosion resistance of metals, including coated metals.
At ITW Spraytec, all GALVA Jelt products undergo this test. We have achieved a very high level of performance, well above the market average.

Is cold galvanizing heat-resistant?
By definition, a cold galvanizing coating is resistant to high temperatures, far superior to all other types of coatings or paints, with a minimum standard resistance of 200°C.
The Jelt brand offers cold galvanizing products resistant up to 450°C.

Can a coat of paint be applied over a cold galvanized coating?
Cold galvanized coatings are not designed to be painted. In fact, a cold galvanized coating provides both protection and a glossy finish. To meet specific market demands, some paintable options are available. At ITW Spraytec, we offer GALVA MAT products in anthracite gray, which can be easily painted with any type of colored paint. The paint does not compromise the corrosion protection; it serves an aesthetic purpose.

How do you know if you’ve adequately protected the metal area?
You don’t need to apply a lot of paint for optimal protection; 30 microns is sufficient. However, it’s essential to cover the entire part evenly. To achieve this, it’s recommended to apply the product in cross-hatching layers. Aerosol packaging is not only more practical but also more economical, as less product is used.

Is the finish of cold galvanizing similar to that of hot-dip galvanizing?
Hot-dip galvanizing provides an ultra-glossy finish that is difficult to replicate with cold galvanizing. However, at ITW Spraytec, three products offer this “mirror-like” finish. These are the GALVA FLASH range.

What are the advantages of galvanized steel?
Galvanized steel offers several advantages, including:
• Corrosion resistance: Galvanized steel is coated with a layer of zinc that protects it from corrosion caused by exposure to moisture, air, and other environmental elements. This makes it an ideal choice for outdoor applications or in corrosive environments.
• Durability: Due to its corrosion resistance, galvanized steel is generally more durable and has a longer lifespan than uncoated steel.
• Low maintenance: Given its corrosion resistance, galvanized steel requires less maintenance than other materials. It generally does not require frequent repainting to maintain its integrity.
• Mechanical strength: Galvanized steel retains the mechanical properties of base steel, meaning it remains strong and resistant to high mechanical loads.
• Aesthetics: Galvanized steel has a bright and attractive appearance, making it a popular choice for a variety of architectural and decorative applications.
• Cost-effectiveness: Although the initial cost of galvanized steel may be slightly higher than that of uncoated steel, its advantages in terms of durability and low maintenance can lead to long-term savings.

These advantages make galvanized steel a versatile material widely used in many industries, including construction, automotive, manufacturing and many others.