Sculpting in clay means your real work is far from over once you have sculpted your ‘masterpiece’! Your next job now is to create a mould and then cast your figure in a durable material such as cement, hydrostone, fibreglass, aluminum or bronze. Cost dictates what material you use, but also the complexity of the piece. Paradoxically, a figure like Icarus leaping in the air could only be done in metal.
Moulding and casting is the exact opposite of the creative clay work, since most of it is physics, chemistry and mathematical calculations. To think that these were my least favorite subjects in school! What keeps me going are Rosemary at the studio and the Artisans at the metal foundry who are passionate about mould making, wax and molten metal. These wonderful people will spend hours helping me figure out how to turn my whimsical idea into a piece that will last centuries.Humbling!
Casting steps – Abbreviated version!
The first step in mould making is to separate your sculpture into a puzzle that can be taken apart and assembled easily for casting in the material of your choice. This takes a lot of head scratching when your piece is an intricate 3D. I used fine metal rectangles to delineate the components for Icarus and also plastiline clay to secure in place. I then created a mould of each piece. First a rubber mould then a plaster mould or mother mould to hold the first one in place.
I won’t go into every detail, but the next picture shows the gooey rubber being poured on in a transparent film to capture every bump and crevasse. You need at least 3 coats. The rubber is flexible and yet very resistant. Many masks in sci-fi movies are made this way. The coats take many hours to dry. Next, you need to mix the plaster for your mother mould and apply that in coats as well over your rubber surface. Those also take time to dry.
The challenge is to make all the pieces of the mould fit together. Where do you put the joints, the keys? How do you avoid negative angles that are guaranteed to prevent the mould from coming off once the piece is poured? Mechanical engineering would often be an asset!
It took me years to reconcile myself with the fact that as much as I dread mould making, my art cannot be born without it.
To be continued!