The video shows first the two types of required canes being made and arranged in a pattern on a ceramic plate. After the canes are fused together, a thick, cylindrical bubble of glass is rolled over the canes so that they become attached. After re-heating, glassblowing is used to make the beaker.
As is the case with virtually all historical glass, the cane cores are transparent. A gather of clear glass is lowered into a pot of opaque, molten, white glass, thinly coated, and after this hardens, another gather of clear glass is made. This is attached to a post or piece of glass on the end of another metal rod. It's elongated. And a cane of about a length of 20 feet is drawn.
The blue cane consists of four layers: a transparent core, a layer of opaque white, (excess white glass is cut away from the end), and a layer of blue. The blue glass is then very thinly coated with transparent. This is attached to a post and pulled about 20 feet long. The canes are cut to lengths of about 4 inches, and the canes are placed on a ceramic plate in patterns, and the plate is heated to a temperature of about 1,400 degrees Fahrenheit.
The vessel begins with a substantial gather of transparent glass. A bubble is blown in. And the gather is elongated to become cylindrical in form. Its diameter must be carefully monitored to be compatible with the length of the cane pickup. At 1,400 degrees, the canes are slightly soft. They're fused and rolled up on the transparent bubble. To avoid the glass sticking to the ceramic plate, the plate has been thinly covered with kiln wash. It has to be brushed off. The glass is reheated and marvered to ensure that the canes and the clear glass stick together.
At a certain point, marvering is done in place and the torque twists the canes. A constriction is made near the tip of the gather. Shears are used to cut free the ball and this results in a short straight line of cane pattern. Reheating and blowing, together with marvering in place, result in the bubble getting larger, the twist getting tighter, and the bubble getting longer. The inflating against the marver also ensures that the lowermost part of the bubble will be thicker than the sides. A constriction is formed near the blowpipe. This will enable the vessel to be broken free of the blowpipe. The bubble is softened and the blowpipe spun. This creates centripetal force that elongates the bubble. The sides are touched, the bottom is flattened, air is blown in, and a rather large gather of glass is added to the bottom edge, then tooled with a grooved roulette tool. And this produces a denticulate pattern in the glass. The punty is added. The neck is broken, and the opening reheated.
As the jacks are held against the glass, the punty is turned in a direction that will tighten the pattern. The soffietta is used to inflate the uppermost part of the vessel. Again, the punty is turned in the direction that will tighten the pattern. Centripetal force elongates the shoulder. The soffietta is used for a final time in preparation for creating the final rim shape. The torque from the jacks and the soffietta results in a tight, tight twist at the top, and a looser twist at the lower half. The vessel is lowered into the annealing oven, the rod tapped. It breaks free, and the vessel is left in the annealing oven for slow cooling.
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