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The discovery of glass thousands of years ago opened a revolution in products and beauty that is maintained to this day in the centres of glass art and technology. Benvenuto glass is one of those centres.

Glass is an enigma – a supercooled liquid that softens directly and then flows when you heat it. But if you cool it too quickly it may shatter and you must not bend it far or it will break. Then again, if you just cool the surface quickly from a special temperature it becomes immensely tough. Maybe not the best of friends for an artisan, it is a demanding bride, and can ‘cut you to the quick’, but when shaped with joy it sings a pure melody.

That’s why to be a master of this material one needs excellence in technology, fine artisanal skills, artistic flair and soul – a feeling for the behaviour.
Vittorio Benvenuto has spent his life achieving understanding of glass and finding the way to “let it sing” such that today he is a master of glass and he welcomes all to Benvenuto Glass. We met him and have visited his atelier and he told us a few of the many tools he uses to create his works of art; meanwhile we were dreaming of new wonders.

Stained Glass and ‘Tubage’ Technology

The most common technology for production of stained glass windows, that has been in use for over 1000 years, utilises lead to connect the pieces of glass. Less than 100 years ago another technique was invented that involved dispensing a non-lead containing paste from a syringe to connect the pieces of glass, coating it with a coloured enamel and melting the paste to seal the glass pieces. This has been referred to as ‘tubage’ technology.

Tubage technology possibly was similar to some of the early cermets (a composite material composed of ceramic or glass – ‘cer’ – and metallic elements – ‘met’ – materials) that consisted of micron sized precious metal particles mixed with a small percentage of fine glass powder.

This technology became core to vacuum sealing of electronic valves and electrodes for ceramic capacitors. Yet, for the stained glass industry it was lost and the challenge for Vittorio Benvenuto and other glass technologists come 1990 was to rediscover the materials and methods. The challenge was accepted and conquered and Vittorio added this to his long list of glass technologies that he offers to share with other artisans.

Since the early years of use of stained glass in cathedrals, glass painting using glazes has been a technique for providing detail to a stained glass window. Benvenuto glass collaborates with artists who create their works using glasses and glazes developed by Benvenuto Mastri Vetrai. Vittorio invites artists to work alongside his team to achieve their most challenging scenes and dreams.

Glass enamelling and fusion

For hundreds of years enamelling of metal shapes has been the technology of choice for coating the metal with a corrosive protecting coloured glass. The technology involves normally three layers, the first to bond the glass to the metal to minimise thermal expansion mismatch. The second layer seals the glaze and provides a chemical barrier. The third layer is the colour coat enamel glass that gives the decorative effect. The challenge is to prevent crazing and pealing of the enamel.

In glass fusion the challenges of melting one glass onto another are multiplied as the glass shapes have significant thickness and are non-continuous. The artist must understand thermal shock resistance, different flow conditions for each glass, and chemical compatibility.

Examples of these technologies used by Vittorio Benvenuto can be experienced by visiting TINAS (This is Not A Showroom) at his works in Treviso. It is a sort of labyrinth in the dark where you are guided by special music and lights on each piece of glass art. There are 6 different works of art that correspond to 6 different glass technologies. It opens your eyes and your soul to the joys of the creations of a glass master.

(This article is reproduced under licence from Energitismo Limited)

Gavin Tulloch

Scienziato e poeta. Ama la chimica, il vino, le donne e l’opera, ma non sappiamo in quale ordine