How are Glass Sculptures Made?
Last week we looked at how bronze sculptures are made, but this time we will be exploring the world of glassmaking – specifically the legendary glassmaking of Murano, Italy.
Murano may well be one of the most recognised centres for art glass in the world. If you look at the work of Italian sculptor Silvio Vigliaturo, you will be immediately drawn to the vivid colours and striking form of his contemporary glass sculptures.
In 1969, Silvio completed a traditional apprenticeship at a local glass works, where he was instructed in the art of drawing by Luigi Bertagna, a disciple of Turin artist Giacomo Grosso, and in painting by Edoardo Ferrero.
Silvio’s flawless attention to detail is owed to the influences of artists Picasso and Miro, and Futurist and Expressionist movements, which is clear to see in vibrant pieces such as Vibrazioni Musicali.
The complex process of creating Murano glass involves employing the ‘lampworking’ technique - using a furnace, torch or lamp to melt the glass, which is then manipulated into shape by blowing and forming with tools once in a molten state.
In the Murano glassmaking process, the glass contains high amounts of silica(silicon dioxide, a natural compound) which is solid in normal temperature conditions, and only becomes liquid at extremely high temperatures.
Carefully administered quantities of chemical compounds are necessary to enable the glass to achieve a sufficiently stable molten state to allow the artist a window of opportunity to manipulate its form and create their masterpieces.
To facilitate this interval, a flux (a chemical agent, like sodium oxide) is added to the silica in order to reduce the temperature to which the silica needs to be heated to become molten. A stabiliser (like calcium oxide) may also be added to the mix to increase durability. These heated compounds are added to molten glass.
At this stage, other raw materials can be added to the glass to produce various effects - sodium to make glass surfaces opaque; nitrate and arsenic to eliminate bubbles; as well as a variety of colouring and texturing substances, depending upon the desired effect.
As the glass passes from a liquid to a solid state, the artist will shape the material. A blowpipe – or canna da soffio- is used to begin the shaping process. Tongs – or borselle – are used to further manipulate the softened glass, and a special tong known as borselle puntata can be used to apply texture to the piece, with its patterned pincers. The piece is often finished by cutting the glass, before it has hardened, with scissors (tagianti).
Over the centuries, many glassmaking techniques have been developed in Murano, including Inclamo (the process of fusing together many different coloured glass pieces into one, while the glass is pliable), Aventuria (embedding flecks of metal, like copper, in clear glass to create stunning effects by reflecting the light), Mezza Filigrana (the creation of sculpture from single opaque glass rods, fused together, then blown and shaped by the artist), Reticello (twisting two opaque glass pieces in opposite directions during heating to create a diamond pattern), and Retortoli (the twisting of two opaque glass filaments into a spiral shape).