While glancing at the wondrous variation of colors and designs of your bowl, you might not realize all the work that went into making it. But behind every quality glass pipe is an artist who, with a set of steady hands, the right amount of flame and keen attention to detail, transformed molten glass like magic. The Techniques of Renaissance Venetian Glassworking by William Gudenrath is really amazing.
The process of blowing a glass pipe should never be understated. In addition to requiring considerable precision, it takes a great deal of experience to make the perfect glass pipe. The Making Glass Tubes with a Bubble on the video presents an alternative method of making glass tubing, one of many techniques that do not require inflation.
In the video, the end of the tube is initially shown being reheated in a small hole in the glassblowing furnace. After the glass was annealed (cooled), one end of a tube was reheated, perhaps by holding the tip inside a small furnace or in a flame, just as modern flameworkers might do. This making of glass pipe must make you cooled. In this process, as the glass softens, surface tension causes the glass to thicken. Eventually the hole closed. Air was immediately blown forcefully into the other end of the tube, and the still soft glass was inflated to form a bulb.