The Statue of Liberty was built using two primary materials: copper and iron. These materials were chosen not only for their aesthetic qualities but also for their durability and resistance to the elements. In addition to the statue itself, the pedestal on which it stands is made primarily of concrete and granite, selected for its structural integrity and longevity. Another noteworthy feature is the statue's flame, covered in 24-karat gold leaf. This gold leaf adds to the flame's visibility and offers long-lasting resistance to corrosion and oxidation.
The most visible material used in the construction of the Statue of Liberty is copper. The outer skin of the statue, which gives it its greenish hue, is made of copper sheets, about 3/32 of an inch thick. Approximately 31 tons of copper were used to create the statue's exterior.
One of the reasons for using copper in the construction of the statue was its malleability. Copper is a soft, malleable metal that can be easily shaped and formed into intricate details. This characteristic made it an ideal choice for sculptor Frédéric Auguste Bartholdi, who created the stunning folds of the statue's robe and the delicate features of her face using this versatile material.
Over time, the copper has undergone a natural oxidation process, forming a green patina on the surface. This patina gives the statue its distinctive color and acts as a protective layer, preventing further corrosion and preserving the underlying metal.
If you're visiting New York City, be sure to buy tickets to see the statue on Liberty Island, where you'll be able to appreciate this fantastic transformation of color.
While the copper skin is the most visible part of the Statue of Liberty, it is supported by an internal iron framework. Alexandre Gustave Eiffel, the engineer behind the famous Eiffel Tower, designed this framework. Eiffel's innovative design used iron bars and trusses to create a flexible yet strong skeleton capable of supporting the immense weight of the copper skin and enabling the statue to withstand strong winds, temperature changes, and other environmental factors.
The iron framework consists of four massive iron columns, which rise from the pedestal and form the backbone of the statue. These columns are connected by iron trusses and crossbars, creating a rigid lattice structure. This lattice not only supports the statue's weight but also allows for the distribution of forces across the entire framework, ensuring the statue's stability and longevity.
The combination of copper and iron in the construction of the Statue of Liberty enabled the creation of a genuinely remarkable and enduring monument. The statue's unique blend of artistry and engineering is a testament to the skill and vision of the individuals involved in its design and construction.
The pedestal of the Statue of Liberty is made primarily of concrete and granite. The concrete forms the core structure of the pedestal, providing the necessary strength and stability to support the statue's weight. The exterior of the pedestal is faced with granite, which offers both durability and an aesthetically pleasing appearance. The granite was sourced from the Beattie Quarry in Leete's Island, Connecticut.
American architect Richard Morris Hunt designed the construction of the pedestal. Hunt's design features a square base, four buttresses, and a balcony that surrounds the pedestal at the height where the statue's base begins. The overall size of the pedestal, including the foundation, is approximately 154 feet. Hunt selected materials that would be structurally sound and readily available, thereby speeding up the construction process.
The pedestal's construction began in 1883 and was completed in April 1886. The process involved excavating Bedloe’s Island to lay the foundation, followed by assembling the concrete core and placing the granite blocks. Due to the scale of the project and the weight of the materials, cranes, derricks, and other heavy machinery were used during construction. Large granite blocks were transported from the quarry in Connecticut to the construction site.
The flame of the Statue of Liberty's torch is covered in 24-karat gold leaf. This was not part of the original design by Frédéric Auguste Bartholdi, who created the statue's torch to be made out of copper like the rest of the figure. The gold leaf was applied during a restoration project in 1986 to mark the statue's centennial. The original torch inside the statue's right hand was replaced due to deterioration and is now on display in the statue's museum.
Applying gold leaf to the flame involved first removing layers of paint and corrosion to prepare the surface. Then, a unique adhesive, known as sizing, was applied to the cleaned surface to make it sticky and ready to receive the gold leaf. Thin sheets of 24-karat gold leaf were then applied meticulously by hand. The sheets are incredibly fragile and must be handled carefully to prevent tearing.
The choice of 24-karat gold was deliberate, as it is highly resistant to corrosion and oxidation, thus ensuring that the flame retains its golden appearance over time. Despite being made of expensive material, gold leaf is extraordinarily thin and does not require much gold. This made it a viable option for this high-profile restoration project.
The gold leaf is expected to last for many decades with minimal upkeep in terms of durability and maintenance. The properties of gold make it a lasting material that stands up well to the elements, including the salty air of New York Harbor, where the Statue of Liberty is located. As gold does not tarnish or corrode, it does not require frequent cleaning or reapplication, making it a practical choice for such an exposed structure.