“Are bronze sculptures made from gold? Why do they cost so much?”

This is a common question. People are shocked to see the price of a limited edition or single edition bronze. After all, bronze metal only costs about $25 a pound. A desktop or table top sculpture may only contain a few pounds of bronze, or at most 20 pounds of bronze. How can they be so expensive?

Well, the explanation has a lot to do with fine art. A bronze sculpture is fine art. Fine art is art that is appreciated for its imaginative, aesthetic, or intellectual content. It is also an activity that requires great skill or accomplishment. Creating a bronze sculpture is a complex and labour intensive process that involves highly trained and experienced people and expensive, specialized equipment.

A bronze is not a manufactured product. You are not paying for a factory item or a mass produced item that you can find online. You are buying a finely crafted single edition or a limited edition piece of art created by an artist.

The bronze metal used in a sculpture is not the primary cost. The actual bronze cost may even be less than the cost of the walnut used to make the base for the sculpture.

The cost of a bronze is made up from many different parts. First, there is an artist that has to make the piece to create the vision that represents the art. The piece is often created in clay or wax. Regardless of how it is created, or even if the artist uses lower cost previously manufactured components as the basis of the sculpture, the work needs to be produced. Depending on the size of the piece this process can take weeks or even years to realize the vision.

It is not always that a sculptor will take a hammer and chisel and carve a figure out of marble or plaster which is then cast in bronze. An artist can use any found object to create a work of art, even manufactured objects, after which the sculpture is cast in bronze. 3D printed objects can also be used to create original pieces for casting.

It is only when the piece is finished that it is cast in bronze. The casting process always replicates an original piece so all bronze sculptures are copies of original work. A silicone rubber mould is made of the piece. Once the mould is produced a decision is made to create a single edition or a limited edition of the work. Limited editions of a piece spread the cost of the mould and art creation over a number of copies and so can reduce the cost. Single editions or unique sculptures must include all costs in the one piece.

A typical desktop sculpture, approximately 10 inches by 8 inches by 8 inches in size, would likely require about a gallon or 4 litres of silicone rubber. This costs about $200. An experienced mould maker is required to plan the mould as undercuts and three dimensional complexities in the sculpture may require that the mould be produced in multiple parts. The original sculpture may need to be destroyed in order to create the moulds. Further, a hard shell or casing to hold the rubber is required. It can cost $500 to $2000 to create the mould depending on the size and complexity of the piece.

Next, a wax copy of the sculpture is made using the mould. A special wax is used that will vaporize with high heat and so not leave a residue when casting. The wax is melted and poured into the silicone rubber mould to create a copy of the original sculpture. When the wax hardens it is carefully removed from the rubber mould and cleaned and repaired. All waxes are reworked to remove imperfections and prepare for casting. It is far easier to effect repairs in wax than repair a poorly cast object.

Wax feed channels or sprues are attached to the wax model so that molten metal can flow into the model when it is cast. An experienced casting technician must do this work as the feed is critical to the success of the cast. Molten bronze shrinks as it cools and hardens. Reservoirs of molten metal must be made available to supply new material into the form as the bronze hardens. Insufficient metal or improper casting temperatures leads to cracking or pitting or other failures in the cast.

The sprued wax is then placed in a steel flask or ceramic shell for casting. Ceramic shells are used for larger castings. These shells are made from a liquid ceramic slurry that is poured around the wax. This slurry, when dry, can withstand the high heat of molten bronze, about 1000 degrees Centigrade or 2000 degrees Fahrenheit. For steel flasks a special plaster known as investment is used. This plaster is poured into the flask where it hardens around the wax. Investment, when heated to about 700 degrees Centigrade, becomes porous to air. This allows gases to escape if the flask is placed under a vacuum when the metal is poured. Air pressure helps push the molten metal into all parts of the model.

The prepared model is then heated to melt the wax, which runs out leaving a void in the flask or shell. Molten bronze is then poured into the container to fill the void, thus creating an exact replica of the original sculpture.

Once the bronze is cool the ceramic shell is broken or the investment plaster is removed from the steel flask to release the sculpture. The casting gods are now rewarded if the cast was successful. The metal feed sprues are cut off and a skilled metalwork artisan will chase and repair any flaws in the casting.

Any secondary parts such as previously cast sculpture parts or mounting supports are welded to the sculpture with an acetylene torch. The cast bronze is polished and the artisan will apply a patina to the sculpture. A patina is an oxidizing chemical that can turn the metal brown, black, green, blue, or other colours depending on the chemicals used. A skilled artisan is required to apply the patina. Typical foundry costs for melting bronze and casting a large size sculpture can range from $1500 to $3000.

In my case I do my own casting using jewellery size casting equipment. By not using a foundry I can keep my casting costs below $1000 for a large sculpture. However, due to the smaller size of my casting equipment I am limited to 1.5 kilograms in the amount of bronze I can melt and cast in any one pour. My sculptures are often cast in parts using different alloys. I can also incorporate silver and gold and precious stones in my sculpture. This offers more artistic variation than a traditional single cast bronze with a dark patina.

Add to this the cost of art shows, booth rentals, travel, gallery commissions (typically 50%), insurance, studio rental, equipment costs, and there is not much money left for the artist. Do you still think the cost of a limited edition or single edition bronze is unreasonable?