Rusting Handrailing Nails
In the picture above, you can see the
nails on the left starting to rust, while the nails on the right are
Now for the big question, why is this happening?
There's a very good chance, that these nails were driven in by a pneumatic nail gun or a nail gun that is powered by an air compressor, gas or electricity. These nail guns use extremely high levels of power to drive these nails into the wood.
With these high levels of power, the mechanical nail driver strikes the head of each nail, it can often chip a small piece of metal or any metallic coating off of the nail. Some exterior nails that are used for building decks and hand railing are zinc coated.
This zinc coating, often gives the inexperienced contractor or homeowner the illusion that they will last as long as galvanized nails. Often this isn't the case.
Once the zinc coating is chipped off of the nailhead, the metal used to form the nail is now exposed to the weather and moisture. This will cause the nail to rust eventually.
Home Repair Tip: Instead of using zinc coated nails, use galvanized nails. These nails are made from galvanized metals and have no coating on them. Expect to pay an additional 20 to 50% more for each box of galvanized nails, but they're worth it and I would recommend using them in a situation like this.
Zinc coated screws can also become chipped and rust, like the zinc coated nails.