What are Sculptures Made of?
If you have ever spent any time staring admiringly at an intricately formed statue or sculpture you may have found yourself asking “what are statues made of?” or indeed “how are sculptures made?”.
There are several basic methods of creating a sculpture. These include carving (using tools to etch into stone or wood, for example), modelling (manipulating and shaping soft materials like clay or wax) and casting (pouring a molten material into a mould).
In this article, we will be exploring how bronze sculptures are made.
To make metal castings like bronze, a technique known as the Cire Perdue or 'Lost Wax' method is employed – a technique which remains largely the same as it was in 2,000 BC, whereby molten bronze is poured into a ceramic mould - known as an 'investment'. This lost wax method can also be used for casting other metals like gold, silver and stainless steel.
The process begins with the artist initially modelling the form with a malleable material like clay, wax, or even plasticine. This initial piece is known as the 'master' form. In just the same way as if they were painting or drawing a picture, each artist will have their own preferred techniques and materials for creating this initial 'master' form.
Celebrated wildlife sculptor, Hamish Mackie, sculpts his over a steel and aluminium anatomical skeleton known as an armature out of clay, plaster or wax (depending on where and what he is sculpting).
William Montgomery prefers to use plasticine to form his stunningly detailed animal figures, as he says the oil-based medium allows more time to create intricate and accurate compositions synonymous with his work.
And Fred Gordon, uses heated sheets of wax to sculpt his - using quick and fluid gestures to capture the motion and vitality of his subject, before applying more intricate detail once the wax has cooled.
The next stage of the process is undertaken by a specialist Foundry, like the Lockbund Sculpture Foundry in Oxfordshire, Atelier Fine Art in Hampshire, and Castle Fine Arts Foundry in Stroud.
A silicon rubber mould is made over the 'master' (to form a negative of the original) and molten wax is slushed into it, then poured out and allowed to cool to form a hollow wax pattern. The seam line where the mould fitted together is then smoothed out, and (in the case of large and intricate pieces) the sculpture is cut up into castable sections.
A series of wax runners and risers is fitted to these castable sections, which allows the molten bronze to flow in, and to let the gases escape.
The wax is coated inside and out with liquid ceramic and grit, and built up in layers to form a strong heat-resistant mould around the wax. This is then baked upside down in an oven, which allows the wax to melt out - hence the term 'lost wax'.
The loss of the wax forms a negative space of the 'master'. This is the ceramic mould (or investment) into which molten bronze can be poured at a scorching 1200°c. When the bronze has cooled, the ceramic is chipped away, and the sprues are cut off. The bronze is then placed in acid in order to break down any remaining traces of the ceramic mould from the surface detail.
If the bronze has been cast in several pieces, it would then be welded together and chased - a highly skilled process recreating any surface detail.
At this stage, the sculpture is ready to have heat and various chemicals applied to it, in order to form the finished patina – the application of colour or film to enhance the look of the piece.
Some sculptors like to be involved in the patination process - Hamish Mackie does his own patination, considering this as important as the colour of paint on a canvas.
Because a mould can be cast more than once, this allows the artist to create 'editions'. In a similar way to limited edition prints, an artist will often limit the number of castings to a defined total amount and carve this into the casting during its creation to authenticate the piece. For example, the artist may carve their signature and mark the edition as 3/12 – in this instance, meaning that it is the 3rd edition cast of a total run of 12 sculptures.
Now that we have learnt a little more about the lengthy and costly process involved in creating our artist's bronze sculptures it is easy to see them as a true labour of love, and worthy of their value!
In our Gallery you will find an array of sculptures which have been painstakingly created using a metal casting process. Most (like the work of Adam Binder, Gill Parker, Philip Jackson, Jenna Gearing and Michael Talbot, to name just a few) are cast in bronze, and some are formed in stainless steel (see work by Rudy Morandini, or Silver Swan by Simon Gudgeon) or hallmarked silver (like Hamish Mackie's Swifts - Silver). We even have sculptures created using complex glassmaking and lampworking techniques (more about this, and Silvio Vigliaturo's work next week).
There are many labour intensive stages to the process of creating the finished sculptures that you will see in our gallery, or in sculpture gardens like the stunning Sculpture by the Lakes in Dorset, created by renowned sculptor Simon Gudgeon.