Choosing the right nail for the job can be a daunting task. If you've ever spent time in the fastener section of your local hardware store, you know that length and diameter are just the beginning. Nails also come in different finishes. Coated nails make up a significant part of the selection because so many nails require the protection that a coating provides.
Nails are most often coated to protect them from the elements and increase their effective lifespan. Some nails are coated and textured to give them better gripping power in difficult materials. Occasionally, nails are given different finishes to either improve their appearance or protect the appearance of the materials in which they are used, such as nails plated with stainless steel to prevent streaking when exposed to a corrosive environment like salt water.
Nails that are given a coating of zinc are called galvanized nails. The zinc coating, although not entirely impervious to corrosion, serves as a long-wearing sacrificial barrier to the steel underneath. Nails that are dipped in molten zinc are the most corrosion-resistant of the galvanized varieties because the zinc layer is relatively thick in comparison to electroplating or tumbler coating. Hot-dipped galvanized products have a characteristic flat gray color and a somewhat rough appearance.
Electroplated galvanized nails have such a bright, shiny appearance that the zinc coating is sometimes mistaken for nickel. Nails that have a true nickel coating are rather expensive and are normally used for appearance purposes. Nickel-plated upholstery nails, for instance, have a bright, shiny finish and usually have ornate heads as well.
When resistance to weather and corrosion is an issue, hot-dipped galvanized nails are the top choice. Such nails are normally used where appearance isn't an issue, so the rough, gray coating doesn't matter. Electroplated galvanized nails do have bright heads, but they sacrifice some corrosion resistance, and those bright heads won't stay that way long in harsh conditions. Nickel-plated nails are normally best used for specialty and decorative use.