Brad nails are available in electrogalvanized as well as hot dip galvanized forms. While hot dip galvanizing provides a thicker layer of coating and hence more corrosion resistance, electroplated or electrogalvanized brad nails have a better aesthetic appearance and are better suited for closed fitted parts. Both processes entail a coating of zinc on steel.
The average thickness of hot dip galvanized coating is about ten times more compared to electrogalvanized brad nails. Thus, when it comes to outdoor exposure, the hot dip galvanized brad nails stand a better chance as opposed to electrogalvanized versions.
Difference in Methods
There is a general misconception about the terms electrogalvanized, which also refers to electroplating and hot dip galvanizations. Several times, the term galvanized might be used for electroplated brad nails, leading people to believe that this refers to the hot dip galvanization technique. The primary difference between the two finishes lie in their techniques. In the hot dip galvanizing method, the coating comprises a mix of zinc and iron. The uniform coating provides superior protection at edges and corners. With this process, there is metallurgical reaction between steel and iron, causing multiple alloy layers of iron and zinc. Both the alloy layers and pure zinc coating provide additional protection in the event of damage or scratches to the surface.
In the case of mechanical electroplating or electrogalvanization, there is a flash type copper coating after, which the brad nails are tumbled inside a barrel containing zinc powder and glass beads. As per ASTM standards, coating thickness should range between 0.2 and 4.3 mils. While the hot dip galvanized brad nails have density of 0.6 oz/ft square/mil, the electrogalvanized brad nails have densities of 0.45 oz/ft square/mil. Thus, with a hot dip galvanized surface coating, there is approximately 30 percent extra zinc content in each unit compared to the electrogalvanized coating. Since it is the zinc, which is responsible for corrosion resistance, the hot dip galvanized technique offers greater protection.
Electrogalvanized Coating Structure
The coating of electrogalvanization comprises round zinc particles held together loosely. The bond between zinc-zinc or zinc-steel is much weaker compared to the bond forged in hot dip galvanization. The thread, edge as well as corner coating thicknesses are much lower due to the deposition technique involved in electrogalvanization process.
When it comes to electrogalvanized coating, it is much thinner and has less adhesive strength as compared to hot dip galvanization of brad nails. The edges of bolts and nuts tend to have a thinner coating and hence offer lesser degree of resistance to corrosion. Due to these faults, the overall protection offered by the fastener is compromised. Hence, if you are looking for long-term protection from damage or corrosion, make sure to invest in hot dip galvanized brad nails.
If you want a shiny, lustrous surface, consider electrogalvanized brad nails as these surfaces typically have a smoother, brighter appearance. In the case of hot dip galvanized brad nails, the surface is duller owing to more quantity of zinc. Depending on where the brad nails will be located and the amount of exposure to the elements, as well as the cost allocated to the process, you can choose between the cheaper electrogavanization and hot dip galvanization, which is more expensive.