Glassmaking technique: free-blown glass
About this video
Free-blown glass vessels are shaped only by blowing through a blowpipe and using tools, with no mold. To make a simple bottle, glass is gathered, rolled on a marver, blown and stretched into a tube, inflated into a body, moved onto a pontil, opened at the neck, and slowly cooled in an annealing oven.
You'll be able to
- explain how free-blown glass is different from mold-blown glass.
- put the steps of making a free-blown bottle in order.
- explain what a marver, a pontil and an annealing oven are for.
Key words
- blowpipe
- A long tube used to gather molten glass and blow air into it.
- marver
- A smooth surface that glass is rolled on to give it a cylindrical shape.
- pontil
- A glass-tipped metal rod attached to the bottom of the vessel to hold it.
- annealing oven
- An oven where glass is cooled gradually so it doesn't crack.
Transcript
(soft flute music) Voiceover: Free blown glass vessels are shaped solely by inflation with a blowpipe and manipulation with tools. (soft flute music) To make a simple bottle, molten glass is gathered onto the blowpipe, then rolled back and forth on a smoothed surface, the marver, to give it a cylindrical shape.
(soft flute music) A small bubble is blown in the glass. The blowpipe is spun end-to-end in order to stretch the bubble out to form a long narrow tube. The thick mass of glass at the end of the tube remains soft and is immediately inflated to form the vessel body.
(soft flute music) The bottom is flattened. (soft flute music) To shape the bottles mouth, a glass-tipped metal rod, the pontil, is attached to the bottom of the vessel. (soft flute music) Drops of cold water are applied and a sharp bang on the blowpipe causes the neck to break.
(soft flute music) After reheating, the opening can be reshaped. (soft flute music) A gentle tap on the pontil easily breaks the finished vessel free. (soft flute music) It can then be gradually cooled in an annealing oven. (soft flute music)
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