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The beginning of glass blowing started nearly fifteen hundren years earler than 1st century account in Mesopotamia where potters fused sand and minerals while firing their clay into glass. This very first piece of the glassblowing art was a glass tube and blow a bubble at the end, creating the first blowpipe.

Mold BlowingModern Glass Blowing

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Mold blowing

Mold-blowing was an alternate glassblowing method that came after the invention of free-blowing during the first part of the second quarter of the first century A.D. A gather of molten glass is placed on the end of the blowpipe which is then a wooden or metal carved mold. In this way, the shape and the texture of the bubble of glass is determined by the design on the interior of the mold rather than the skill of the glassworker.Two types of molds, namely single-piece mold and multi-piece mold, are frequently used to produce mold-blown vessels. The former allows the finished glass object to be removed in one movement by pulling it upwards from the single-piece mold and is largely employed to produce tableware and utilitarian vessels for storage and transportation. Whereas the latter is made in multi-paneled mold that join together, thus permitting the development of more sophisticated surface modeling, texture and design. The Roman leaf beaker which is now on display in the J. Paul Getty Museum was blown in a three-part mold decorated with the foliage relief frieze of four vertical plants. Meanwhile, Taylor and Hill tried to reproduce mold-blown vessels by using three-part molds made of different materials. The result suggested that metal, in particular bronze, molds are more effective in producing high-relief design on glass than plaster molds and wooden molds. In view of this, the development of the mold-blowing technique has enabled the speedy production of glass objects in large quantity, thus encouraging the mass production and widespread distribution of glass objects.

In Modern Content

The transformation of raw materials into glass takes place around 2400°F (1315°C); the glass emits enough heat to appear almost white hot. The glass is then left to "fine out" (allowing the bubbles to rise out of the mass), and then the working temperature is reduced in the furnace to around 2000°F (1100°C). At this stage, the glass appears to be a bright orange color. Though most glassblowing is done between 1600–1900°F (870–1040°C), "Soda-lime" glass remains somewhat plastic and workable as low as 1350°F (730°C). Annealing is usually done between 800–900°F (430–480°C). Glassblowing involves three furnaces. The first, which contains a crucible of molten glass, is simply referred to as "the furnace." The second is called the "glory hole", and is used to reheat a piece in between steps of working with it. The final furnace is called the "lehr" or "annealer", and is used to slowly cool the glass, over a period of a few hours to a few days, depending on the size of the pieces. This keeps the glass from cracking due to thermal stress. Historically, all three furnaces were contained in one, with a set of progressively cooler chambers for each of the three purposes. Many glassblowing studios in Mexico and South America still employ this method.

The major tools involved are the blowpipe (or blow tube), the punty (or pontil), bench, marver, seers, blocks, jacks, paddles, tweezers, and a variety of shears. The tip of the blowpipe is first preheated; then dipped in the molten glass in the furnace. The molten glass is 'gathered' on to the blowpipe in much the same way that honey is picked up on a dipper.Then, this glass is rolled on the m of marble, but today is more commonly a fairly thick flat sheet of steel. This forms a cool skin on the exterior of the molten glass and shapes it. Then air is blown into the pipe, creating a bubble. Then, one can gather over that bubble to create a larger piece. Blocks are ladle-like tools made from water-soaked fruit wood and are used similarly to the marver to shape and cool a piece in the early steps of creation. The bench is a glassblower's workstation, and has a place for the glassblower to sit, a place for the handheld tools, and two rails that the pipe or punty rides on while the blower works with the piece. Jacks are a tool shaped somewhat like large tweezers with two blades. Jacks are used for forming shape later in the creation of a piece. Paddles are flat pieces of wood or graphite used for creating flat spots like a bottom. Tweezers are used to pick out details or to pull on the glass. There are two important types of shears, straight shears and diamond shears. Straight shears are essentially bulky scissors, used for making linear cuts. Diamond shears have blades that form a diamond shape when partially open. These are used for cutting off masses of glass. Once a piece has been blown to its approximate final size, the bottom is finalized. Then, the piece is transferred to a punty, and the top is finalized. There are many ways to apply patterns and color to blown glass, including rolling molten glass in powdered color or larger pieces of colored glass called frit. Complex patterns with great detail can be created through the use of cane (rods of colored glass) and murrine (rods cut in cross-sections to reveal patterns). These pieces of color can be arranged in a pattern and 'picked up' by rolling a bubble of molten glass over them. One of the most exacting and complicated caneworking techniques is 'reticello', which involves creating two bubbles from cane, each twisted in a different direction and then combining them and blowing out the final form.

   
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