The history of the dial glass

The city of Pondicherry in South India has a history soaked in mysticism and philosophy. Excavations of glass beads, whose age has been dated to around 2500 years, prove that there had been trade relations between the advanced civilisation of ancient Egypt and Pondicherry even before the time of Cleopatra. At the time when the glass jewellery originated, glass was only produced in Egypt. The Rosicrucians designated Pondicherry as one of the 12 most important spiritual places in the Middle Ages. In the 19th and 20th century, it was the only French colony on Indian soil and therefore became the refuge of Sri Aurobindo, who, as a former freedom fighter, had taken refuge there from the English in “inner-Indian” exile. Eventually, Pondicherry became the cradle of Auroville, whose centre is about 15 km as the crow flies from the outskirts of Pondicherry.

In the course of the philosophical flair of this city on the Bay of Bengal, the diamond-polishing factory “Aditi Diamonds” was also founded in 1981. Traditionally, the diamond cutting industry sits just on the opposite side of the Indian subcontinent, on the west coast, in Mumbai and a little to the north, in Surat. But the German founder of the polishing factory was primarily in search of philosophy, not business success. And so, in 1981, a trade was born in Pondicherry that initially felt a bit like a penguin in the Ötztal Alps.

One day, in 1993, the owner of the polishing factory was asked to visit a very wealthy citizen of Pondicherry, one of the sponsors and coordinators of the Matrimandir, which was then under construction. After working on the building for more than 23 years, they had reached a point where they no longer knew what to do. The task of providing the Matrimandir with an outer shell of pure gold was a task not to be undertaken. Since the building was 100 % financed by private sponsors, it not only seemed impossible to master the challenge financially, but they also had no idea how to approach the technical side of the project.

Studies of large gilded buildings, or parts of such buildings, had led to the trail of a French company that had gilded the torch of the Statue of Liberty in New York, the Cathedral of the Invalides in Paris and several other large landmarks using the gold-leaf process. But an offer from this company for the complete gilding of the Matrimandir was so astronomical that the idea of this method was immediately abandoned.

The owner of the diamond polishing company, also one of the main promoters of the Matrimandir’s construction project, was no stranger to the area. He not only cut diamonds in Pondicherry, but in the meantime also had a powerful team in Germany that produced jewellery, i.e. could handle gold. The Indian polishing factory had reached a considerable size, produced up to 3000 diamonds a day with a staff of 300 men at that time and was by far the largest foreign exchange earner for the state of Pondicherry. Once before, the entrepreneur had solved a problem at the Matrimandir that had to do with gilding and could not be mastered in India. And so it was agreed to put the problem in the hands of the German-Indian team around the diamond polishing company Aditi Diamonds.

To reach a goal where you don’t know the way there, it’s often best to just set off and make course corrections once you’re on your way. This is how the process of gilding leaves began. But they had not reckoned with the nature of South India. A rock bee, which, in the flat area around Pondicherry, considered Matrimandir to be the highest rock, apparently found the gilded façade elements ideal for attaching its honeycombs to. The bee, much larger and more aggressive than the usual honeybees, looks for places out of reach of its enemies, and after the queen has decided on a place, within about an hour the swarm of workers builds a honeycomb up to 1.5 metres in size, which normally hung from an overhanging rock, but in our case now from a gilded facade pane. The bees are very aggressive and any potential enemy that comes too close to the comb is attacked by a warrior squadron. The gold leaf gilding apparently magically attracted the bees, so that soon up to 40 bee colonies were hanging huge honeycombs on the matrimandir, and thus the building activity was considerably impaired by the aggressive animals.
Together with several other problems, the attempt at gold leaf gilding had to be discontinued after one year. What now? The only solution seemed to be to protect the gold with a glass coating. For example, a gold tile was developed in three years of research work in Germany, in which gold leaf is welded into glass in a vacuum process. The process was patented, the tile tested according to all possible procedures.

Finally, a first façade element was fitted with the new gold tile and taken to the south of France to present it to Roger Anger, the building’s architect.

The latter lived on a hill in Le Crestet in an old chateau of the former counter-popes from Avignon, rebuilt with a modern studio for his work. Against the backdrop of the ancient walls, with a far-reaching view over the valley, the German entrepreneur and his Swiss technician carried the result of more than three years of work into the inner courtyard of the castle in the early summer of 1997, their hearts pounding and awaiting Roger’s verdict with mixed feelings. And he was thrilled!
So finally the vacuum gold tile became the key to gilding the largest completely gilded building in the world.

However, the production of 2.5 million tiles with pure fine gold, with a total gilded area of 4500 square metres, was not only a financial and technical challenge, but also an organisational one. Vacuum furnaces for fusing glass were designed by an engineer from the Deggendorf shipyard and shipped to India, machines for precision cutting of gold leaf were designed, ultrasonic equipment for cleaning the glass and a plant for demineralising cleaning water were imported. In the end, about 100 people worked in shifts to produce up to 4000 gold tiles per day and bonded them with a vacuum mixing and dosing system imported from Switzerland using the highest quality multi-component silicone.
However, the invention of the multilayer vacuum glass tile was not the only interesting idea to emerge from the research work at Matrimandir. In the environment of diamond cutting and jewellery production, another idea matured in the experimental studios in Lower Bavaria and the production facilities in southern India: melting diamonds into glass.