Let's start right from the beginning ... Some (quick) mention of the chemical composition of borosilicate

The latter is a glass type of modern era, and was made in Germany by the chemist Otto Schott between 1887 and 1893, when it was actually patented under the name "Duran".

Its composition results a substantial amount of boron and only a minimum amount of soda, a composition which, given the function of the melting element and the mobile nature of the soda, gives this type of glass to one side more heat resistance and, on the other, greater stability once the machining process has ended.

How was borosilicate used yesterday? And today?

The first use of borosilicate glass was therefore in the chemical-pharmaceutical sector (test tubes, cylinders, amphibians) and in the food one (glasses, pots, and bottles), given the more developed ability to withstand acidic or aggressive surfaces. The subsequent creation of the American brand Pirex and the opening of American factories in France made it possible that from the 1920s onwards in these two countries the processing and use of this material became more widespread and open to experimental results.

Only later, borosilicate began to be used in the field of art, and more recently, from the early 1980s, it was able to find its own space within Murano's working practice.

Murano Glass VS Borosilicate: when boron is disadvantageous and when it isn’t

Still considered as a sophisticated and niche alternative to the island's lampworkers, the use of borosilicate glass has some disadvantages and some strengths compared to that of sodium-calcium glass.

• Due to the lower expansion coefficient (33 compared to 104 of "Murano glass"), borosilicate needs higher temperatures to reach the melting point and therefore to be in the conditions of work, which involves the use of burners (in jargon cannelli) more powerful, and therefore a greater consumption of gas and oxygen and higher costs.
• In addition, due to the highest melting point, some (very few) elements such as silver and the oxide specific for transparent clear blue color are incompatible. Therefore, it is not possible to cover that particular color range because the necessary elements would melt before the glass itself, making it impossible to properly amalgamate with the base material.

In spite of these deficits, borosilicate glass has several positive properties compared to the most common sodium-calcium.

This latter peculiarity allows the craftsman or artist who uses borosilicate to embark into boldest aesthetic evolutions, counting on the possibility of making larger objects and experimenting more courageous forms.

Particularly easy is the connection between empty and full sections (such as, for example, a bowl and a stem of a chalice), a condition that induces borosilicate lampworking Masters to deepen the blowing technique of glass compared to that of full glass: here because are most frequent light and sinuous works, more directed to the delicacy of curved and concave shapes than to the compactness of massive bodies.

The wisdom of the Masters of Murano

A double possibility, therefore, of sodium-calcium and borosilicate glasses, an element of wealth for Murano glass art and for lampworking technique in particular.

But more than a real clash, more than a true competition between two factions, some lampworking masters summarize the matter with a maxim as simple as effective: "For every aesthetic project and every work, the right kind of glass". And how can we give them wrong?

From the beginnings, more than two millennia ago...

Considered one of the oldest processing techniques, dating back to Middle Eastern origins at least 300 BC, the glassblowing in the furnace, or Soffiato all’impronta or Soffio libero, is certainly one of the cornerstones of the Murano art tradition. Glasses, jars, goblets, chandeliers, sculptures, luxury bottles and more: the range of objects that can be realized through these careful passages older than two thousand years is vast and varied in shapes and colors.

Masters' expertise is crucial to the correct execution of the work, and their imagination in understanding and reinterpreting methods and procedures is fundamental to infusing added value to a handmade product, always unique and unrepeatable.

... to the wonder of today (in five key steps)

Here, then, is an ancient knowledge echoed through distant times and lands until reaching the lagoon of Venice, and particularly the island of Murano. A magic that can be described step by step:

1) The starting point is the same for all of them: a long metallic cable hose is inserted into the oven, where molten glass reaches temperatures around 1370 degrees, and, by rotary motion, this hose collects a more or less spherical mass on one end.

2) At this point, the process can vary, depending on the size and the specific features of the developing object: after a first modeling phase, it may be necessary to reinsert the metal barrel into the crucible to collect more glass; to insert the glass mass into a temperature crucible to keep it malleable; or to make it interact with other colored fused glass compounds to obtain a sphere with those chemical elements that, once processed and cooled, will generate those almost unlimited color combinations for which the Murano tradition is famous in the world.

3) Referring to the realization of goti, colorful glasses with shadowing nuances, an authentic classic of Murano's artistic production, the incandescent agglomerate is rubbed on a bed of glass powder of previously selected colors.

4) Analogous operation is then carried out on a surface of murrine, small sections of glass rods that have internally imaginative geometric decorations. At that point, the most delicate moment: blowing inside the cable metal instrument the glass mass is molded until it takes the desired cable spherical shape, a glass rod called puntello is attached to the convex side of it and, with great attention, the work that is being created from is separated from the metal support used for blowing.

5) The section just disconnected (which will become the top of the chalice) is heated and with quick touches of borselle, the iron pliers used for modeling, the spherical mass blown is opened in order to become the " mouth "of the goto. Once the puntello is disconnected from the bottom of what is now a fully recognizable chalice, the work in front of the eyes is the enchantment of a gesture handed down from generation to generation, century to century, in the continuity of an island such as Murano that also today can only leave amazed visitors and experts from all over the world.

Dalle origini più che bimillenarie…

Considerata una delle più antiche tecniche di lavorazione, risalente nelle origini mediorientali almeno al 300 a.C., quella del vetro soffiato in fornace, o “soffiato all’impronta” o “soffio libero”, costituisce di certo uno dei capisaldi della tradizione artistica muranese. Bicchieri, vasi, calici, lampadari, sculture, bottiglie di lusso e quant’altro: la gamma degli oggetti realizzabili tramite gli attenti passaggi di più che bimillenaria memoria è vastissima e quanto mai variegata nelle forme e nei colori.

La perizia dei Maestri è determinante nella corretta esecuzione dell’opera, e la loro fantasia nell’intendere e reinterpretare metodi e procedure risulta fondamentale per infondere valore aggiuntivo ad un prodotto creato a mano, sempre unico e irripetibile.

…alla meraviglia dei giorni nostri (in cinque passaggi chiave)

Ecco dunque un sapere antico riecheggiato attraverso tempi e Paesi lontani fino a giungere nella laguna di Venezia, e in particolare nell’isola Murano. Una magia che si può raccontare passo per passo:

1) Il punto di partenza è per tutti il medesimo: viene inserito un lungo tubo metallico cavo all’interno del forno, dove il vetro fuso raggiunge temperature intorno ai 1370 gradi, e, tramite movimento rotatorio, se ne raccoglie una massa più o meno sferica all’estremità.

2) A questo punto il processo può diversificarsi, a seconda delle dimensioni e delle caratteristiche specifiche dell’oggetto in via di sviluppo: può essere necessario, dopo una prima fase di modellazione, reinserire la canna metallica cava nel crogiuolo per raccogliere altro vetro; inserire la massa vetrosa in un diverso forno detto di riscaldo per mantenerla malleabile; o ancora farla interagire con altri composti vetrosi fusi colorati per ottenere una sfera dotata già di quegli elementi chimici che, una volta lavorati e raffreddati, genereranno le pressoché illimitate combinazioni cromatiche per cui la tradizione muranese è celebre nel mondo.

3) Riferendoci alla realizzazione dei goti, variopinti bicchieri dalle sfumature cangianti, un autentico classico della produzione artistica di Murano, si fa scivolare l’agglomerato vetroso raccolto ancora incandescente su un letto di polvere di vetro dai colori precedentemente selezionati.

4) Operazione analoga viene quindi compiuta su una superficie cosparsa di murrine, piccole sezioni di canna di vetro che presentano internamente dei fantasiosi incroci geometrici. A quel punto il momento più delicato: soffiando all’interno dello strumento metallico cavo si modella la massa vetrosa fino a farle assumere la forma più o meno sferica che si desidera, si attacca una canna di vetro detta “puntello” sul lato convesso della stessa e, con grande perizia, si separa l’opera in fase di creazione dal supporto metallico utilizzato per la soffiatura.

5) Si riscalda dunque proprio la sezione appena staccata (che diventerà la parte superiore del calice) e con rapidi tocchi di “borselle”, le pinze in ferro utilizzate per la modellazione, si va appunto ad aprire la massa sferica soffiata e si definisce meglio la “bocca” del goto. Una volta staccato il puntello dal fondo di quello che è ormai un bicchiere già pienamente riconoscibile, si è di fronte all’incanto compiuto di una gestualità tramandata di generazione in generazione, di secolo in secolo, nell’alveo di un’isola quale quella di Murano che ancora oggi non può che lasciare stupefatti visitatori ed estimatori da tutto il mondo.