Von Poschinger - Glass
From the "gob" to the goblet - the glass stein process
With his breath, fire, and glowing molten glass, with skill that has been handed down over centuries, the glassmaker shapes the glass. Every one is different. Every one a work of art. Unique and individual, like the human being who forms it with his handiwork, skill, and boundless care. Only a human being has the necessary craftsmanship, the skill that turns the mouth-blown glasses into something special, to make them unique pieces full of personal expression, full of soul.
Shaping the hot glass.
The glass designer develops the shape of the wine glass using sketches, measurement diagrams, and the "paper cut". The works foreman is told to make a few sample glasses, and once the shape has been given final approval, production can begin.
In our factory all glasses are blown by mouth. This means that they are made using 100% traditional skills. The glass is made in a workshop, where three to four glassmakers work. The workshop is managed by master glassmakers.
The "gob"-maker takes a small "Posten" (this is what we call the small quantity of molten glass needed to start) from the glass pot with the blowpipe. A "gob" is formed by rolling it back and forth on an iron and carefully measured blowing. The quantity of glass needed for the goblet cannot be taken from the pot all at once with the thin pipe. As soon as the glass ball has set, it serves as a carrier for the next largest quantity of liquid glass. So the "gob"-maker enlarges the "gob" by this "overlapping" process. He forms and cools the glass with the wet spoon-like "Wulgerholz" and blows it up a little before carrying on again. Sometimes the unshaped glass is blown into an "optic", an iron device with blades, grooves or protrusions, or turned, to later produce structures and waves on the surface of the glass. Then the "blower" takes the "Posten", enlarges it by blowing it up, and shapes it with the "Wulgerholz", scissors and tongs, before blowing the molten glass ball into the wooden form, the "model". The forms are made of beechwood or sometimes pear construction wood from our own forests.
The glass turner at work.
The glass is blown into the wooden form.
The "form turner" works in the turning shop, a workshop with turning bench, belt saw and a "damp area" to store the finished wooden forms. The form turner drills and screws a cavity in the beech block, that has been stored in water for months, as it is rotating on the turning bench, using long very sharp turning steels, until it takes on the shape of the future glass. He uses a paper pattern to check, which is called a "cut". At first the cut is slightly folded. At the end this pattern must be flat and fit exactly into the cavity. The "model turner" needs a trained eye and fingertip to feel any unevenness in the form, as the smallest defect in the negative form is automatically transferred to the glass container, and even a skilled glassmaker cannot compensate for this. Only glasses that cannot be turned in the form because they have elaborate shapes or relief decoration are blown in metal forms. Between the blowing processes the model is dipped in the water. In the model a strong and porous layer of charcoal forms even after the first use, which can absorb a very large quantity of water. The blowing creates a layer of steam between the form wall and the glass surface. This gives the glass its incomparably smooth surface and protects the wooden form from quickly burning up. On average 150 glasses can be made from one model before the form is burned up.
Before he starts blowing, the glassmaker has to put the glass in the best form and divide the glass up correctly. The glass must not be too hot or it will run, but nor must it be too cold, or it will set too quickly. The blowing technique must also be adapted to the particular conditions, so that as the glass slowly cools down it can fit against the form walls. The surplus glass forms the "moil" over the form opening. It is taken off after cooling, before the edge of the glass is ground, or knocked off by the glassmaker if the glass edge is finished in the furnace. The top part of the goblet now hangs ready on the blowpipe and is taken over by the craftsman sitting on the bench. Meanwhile the assistant has taken a small quantity of glass from the pot with the "iron". The master glassmaker takes glass off with scissors and cuts it at the bottom. Using a skilful hand, pincers and tongs, he pulls the end. With another "Posten" brought to him by the assistant, he starts the base. "He pushes the base up and smoothes the edge with a piece of paper. Finally, the master glassmaker holds the goblet high with the blowpipe and inspects the glass for precision of measurement and purity, using a metal pattern and a critical eye. He then puts it on the fork held by the carrier, who takes it to the cooling conveyor to slowly cool down. Each individual hand movement is handed down over the years and demands dexterity, experience and ability - glass has been made like this for centuries at Poschinger.
Working at the furnace.
With other pieces of glass such as bowls, vases and beer tankards, there are many more stages and techniques. The glassmaker decorates some glass at the furnace with so-called "works techniques".
Cooling the glass.
As soon as it has been made, the glass has to be evenly heated in a "cool furnace" until it almost reaches the softening point, and then slowly cooled down again, to make all parts of the glass expand evenly. Depending on the type of glass, the time spent on the cooling conveyor lasts 1.5 to 4 hours. As most glass objects contain varying amounts of glass (e.g. the base of a vase is thicker than the walls), if they were to cool down suddenly and unevenly in the air, this would lead to such great differences in tension that they would cause the glass stein to break.
After cooling the glasses go through a few important stages:
Removal of the top.
A diamond or steel pen is used to score the place to be removed (this lifts the surface tension) and then a flame directed at exactly the same place heats it up. The top drops off horizontally at the scored place.
Surface grinding or melting the neck edges.
The glasses still have a sharp uneven edge. Surface grinding takes place either on the horizontal grinding disk or a belt grinding machine. In addition, the inside and outside edges are missed. When glasses have thin sides, particularly glass goblets, the edge is melted again. The glass edges are heated again by flames on a special melting machine until they become soft. The edge is rounded off.
With vases, for example, the so-called moil is ground on the base of the piece concerned. This removes the place that stuck to the glassmaker's blowpipe when the vase opening was being made and grinds it clean away.
The final stages.
After these many stages, each individual glass is checked again, signed, labeled and packed. Glasses that still have to be ground, engraved or painted go on to the "Decorating" stage.
Decorating the glass.
Glass grinding.This method of decorating glass steins and other products gives it sparkle and brilliance by breaking up the light. In order to obtain an even decoration, the glass is drawn on (divided up) before being ground. Horizontal and vertical lines are drawn to divide up the glass as desired using water-resistant dye, lithographic chalk, or similar substances. The main lines are drawn in roughly with silicon carbonate disks. This is called the "preliminary tear". Diamond grinding disks with coarse grinding are used. To cool the glass and to clean the grinding disk, water is passed constantly onto the grinding stone. With this process the grinding is rough and mat. Then the glass is ground with fine corundum brick to give a polishable surface. During polishing fine layers of glass are removed. For polishing wheels poplar wood disks are used first, pressed cork disks in combination with pounce for polishing, then, in the second stage, the "fine polishing", felt or brush wheels coated with aluminum oxide are used as the polishing agent.
Glass engraving.Glass engraving is also referred to as "glass cutting". Using extremely small copper wheels, diamond needles and lubricating gel, engraving can produce the finest and most detailed ornamental decorations. Portraits, lettering, animals and other motifs contrast with the generally geometric shapes produced by grinding on the stein
Glass painting.The colors used most frequently on glass are the so-called "melt colors". To produce these colors, the individual components and the glass batch are mixed in dry and powdered form in certain proportions. They are melted into the glass, and when they turn into soft and hot liquid they are put into water. The flux sets and breaks up into little glass crumbs. These are then turned into very fine powder. Before processing, the colors are mixed with turpentine or similar oils and painted onto the glass with fine brushes. The decoration is then burnt or melted on in the "baking furnace". The melting process makes the decorations form a fast insoluble compound with the glass. Some paintings are also done in pure gold, silver or platinum.
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