From the earliest civilisations to contemporary art installations, metals have been a medium of choice for sculptors. Metal offers a range of physical properties that can bring diverse aesthetic and structural attributes to a work of art. But to fully appreciate this, it's important to understand the basic science behind it - metallurgy. This post explores some key metals involved in sculpture-making, their pros and cons, and how their value influences artists' choice.
Metallurgy: The Backbone of Metal Art
Metallurgy is a domain of materials science that studies the physical and chemical behaviour of metallic elements and their alloys. It involves extracting metals from their ores, refining them for use, and creating combinations of metals (alloys) that have desirable properties such as increased strength, improved corrosion resistance, or enhanced malleability. This science plays a fundamental role in metal sculpture, shaping the possibilities and boundaries of what can be achieved.
Copper
Copper, is a ductile and corrosion-resistant metal, and more of a traditional choice for sculptors.
Pros: Copper is easy to work with, allowing for detailed work. Its natural reddish-orange hue offers unique color potential, and it develops a green patina over time, adding to its visual appeal.
Cons: It's softer and less durable than other metals, and it's relatively expensive.
The 'Statue of Liberty' is covered in a thin layer of copper and is a testament to the metal's long-standing use in monumental sculpture. Image courtesy of S J Pinkney and licensed under CC BY 2.0.
Gold
Though not commonly used due to its high cost, gold brings a touch of luxury and symbolises wealth and power. It is a soft, malleable and ductile metal, resistant to most acids and is one of the heaviest metals in density.
Pros: Gold doesn't tarnish or corrode, ensuring its radiant aesthetic stands the test of time.
Cons: High cost and softness. Since pure gold is too malleable to be used in sculpture, it is often alloyed with other metals (such as silver, copper and zinc), to make the final piece stronger while keeping its ability to stay shiny.
The biggest solid gold Buddha statue can be found in the Wat Traimit Temple in Bangkok. It is 3.91m high, 3.01m wide and weighs 5.5 tons.
Bronze
Bronze, is created when copper and tin are melted together forming a metal that is stronger than its component parts and more malleable. Esteemed for its strength and ductility, it has an enduring allure for modern and contemporary artists alike.
Pros: Bronze resists corrosion and metal fatigue better than most metals. It's also easily cast, enabling artists to achieve high-detail sculptures. An added benefit is the aesthetic patina it develops over time, adding to its antiquated charm. It can be used on a monumental or miniature scale, it will pick up fine detail and texture or can be highly polished and smooth, it can be patinated or painted and weathers gracefully.
Cons: Bronze is expensive due to the cost of copper and tin, and it requires a foundry for casting, which could further increase production costs.
'Newton after Blake' (1995) by Eduardo Paolozzi, in bronze is displayed on a high plinth in the piazza outside the British Library in London. Image courtesy of Leo Reynolds CC BY-NC-SA 2.0
Aluminum
As the most abundant metal in the earth's crust, aluminium offers a light, corrosion-resistant alternative to traditional sculpture materials. Due to it’s strong affinity for oxygen, aluminium is rarely found in its elemental state but rather as oxides, sulphates or silicates which are widespread. The process of extraction only took place in 1824 and as the process could only produce the metal in very small quantities, aluminium remained rare and more expensive than gold for many years. Later this would change and it would became widely used in many industries and everyday items. Aluminium's ability to form hard yet light alloys with other metals made it particularly useful for aviation and demand for aluminium soared during the world wars. Aluminium is soft, non magnetic and ductile and has a much lower density than other metals, approximately one third of that of steel, giving it one of its most important qualities for sculpture: lightness.
'Angel of the North' (1998) by Antony Gormley is one of the UK's most famous landmarks, showcases the strength and stability of aluminium. Image courtesy Mike Peel CC-BY-SA-4.0
Pros: It's lightweight and resistant to weathering, perfect for outdoor installations. Moreover, aluminium is cost-effective and easily worked, appealing to artists on a budget.
Cons: Its lightweight nature may make it unsuitable for large-scale sculptures that require stability and durability. Also, intricate detailing can be more challenging than with softer metals like bronze.
Iron and Steel
Iron, known for its strength and durability, has been used in sculpture for centuries. The single largest uses of iron is to make Steel, as iron alone is too soft for the strength required for structural value. This is done by taking raw materials such as iron ore and turning it into liquid iron. When the impurities are removed, steel is produced. Steel is made up of 98 - 99% iron concentrate, the rest is carbon. Steel is roughly 1000 times stronger than iron in its purest form. It can also be recycled endlessly and never lose any of its strength.
The main difference between iron and steel is the amount of carbon each metal contains. Anything with a carbon content of above 2% is cast iron. 'The Capitol', in Washington, DC; has a dome made of cast iron. Anything higher makes it the material less ductile and more brittle. Cast iron is not suitable for structural use, and some bridges built in the mid 19th century would subsequently collapse. These were later replaced with wrought iron, which contains less than 0.8% of carbon, meaning it is more ductile, allowing it to bend under loads without breaking. The tallest 'wrought' iron structure in the world is the Eiffel Tower.
Pros: Iron is extremely robust, making it ideal for large, outdoor sculptures that can withstand the elements.
Cons: Iron reacts readily with oxygen causing iron oxide ores. Rust is a common iron oxide and working to prevent this is a constant struggle in structure maintenance as it can compromise structural integrity over time.
"Tilted Arc" (1981) by Richard Serra exemplifies the monumental scale and permanence that iron can achieve. It consisted of a 120-foot-long, 12-foot-high solid, unfinished plate of rust-covered COR-TEN steel. This controversial art installation caused an acrimonious public debate and was removed in 1989 as a result of a federal lawsuit.
Stainless Steel
Following on from iron, stainless steel is an iron-carbon alloy with chromium, which presents a more modern, polished aesthetic and thanks to the chromium it contains, makes it resistant to corrosion.
Pros: Its high resistance to corrosion and tarnishing makes it perfect for outdoor and indoor pieces. Its ability to hold a mirror finish also gives a contemporary appeal.
Cons: The high cost of stainless steel can be prohibitive. Plus, it's hard and often difficult to work with, requiring specialised tools and techniques.
Stainless steel sculpture by Anish Kapoor. Courtesy of Lisson Gallery
Silver
Soft, lustrous, with its mirror-bright shine, silver is the whitest and one of the most reflective of all the precious metals. Although the world may be full of silver objects, precious few of them were works of contemporary art until very recently. In fact, there is scarcely a trace of silver in the entire history of Western European sculpture.
Pros: It is highly reflective and can be polished to a luminous sheen.
Cons: Silver is a relatively scarce metal and more fickle and expensive than bronze. It turns faster from molten to solid, and it erodes quicker. Silver is also a soft metal, which makes it difficult to work with and shape into intricate forms.
'Walking cloaked figures' by Lynn Chadwick in Sterling Silver. Courtesy Pangolin London
In conclusion, the world of sculpture, intertwined with the science of metallurgy, reveals the vast depth and complexity inherent in crafting art from metals. While all these metals—brass, bronze, stainless steel, and others—hold intrinsic value due to their unique properties and characteristics, their worth in the art world often depends on the artist's ability to transform them into captivating pieces. It's the blend of technique, imagination, and the innate essence of the metal that breathes life into an inert substance, transcending it from mere raw material into a conduit of human expression. Therefore, as we explore the art and metallurgy of sculpture, we are reminded that the greatest tools an artist can wield are vision, creativity, and the unique ability to see potential beauty in the rudimentary elements of our world.