What does ‘unique bronze’ mean?
Many bronze sculptures are editions, a mold is made of the original sculpture and via that mold a number of wax replications of the initial sculpture are made.
When a bronze sculpture is unique cast it bypasses this step, no mold is made meaning it can only be cast once, it is the only one in existence.
All of Gray’s bronze sculptures are unique casts.
What is the casting process?
It is called the lost-wax process of casting. When Gray has created a sculpture in wax and wood she takes it to a foundry to be cast in bronze.
At the foundry they create a ceramic mold around the work, then it goes into the kiln where the ceramic shell hardens and the wax and wood burns out and is “lost”.
Next bronze metal is poured into the hollow mold. By this means the image is replicated in bronze.
Each bronze formed this way is termed an “original” as the wax model no longer exists.
Each one of Gray’s sculptures are the only one of that particular subject or design. The tree sculptures originate with small found branches, each of which is distinct and irreplaceable.
Where do you cast your work?
Since 2015 Gray has worked with Craig McDonald and the Garage Art Foundry in Elphingstone.
This kind of non-traditional work has presented challenges for them when casting but despite this they have cast the works with minimal problems.
It is a gamble each time, with unique works, if they don’t cast properly it may be impossible to repair and then all the time and effort gone into making the work is lost.
Luckily bronze is a very forgiving medium and many casting flaws can be repaired or worked with.
How do you get the different colours?
Once the work is picked up from the foundry Gray will refine it with some electric and hand tools, then it is ready for her to apply the patina.
Patina is the surface colour treatment of a bronze sculpture created from a chemical change in the surface of the bronze when different chemical solutions are applied to the surface of the sculpture along with the catalyst of heat.
The alchemy behind the variety of colours which is possible with a patina on bronze is so extraordinary with different chemicals producing different colours, you never know exactly what you are going to get, it’s fun to experiment.