Glass blowing refers to glass forming technique that involves inflating molten glass into a bubble, also known as parison with the aid of a blowpipe. A person who blows glass is referred to as a glass blower, gaffer or glass smith.
History of the Art
The art of glassblowing can be dated back to 300 BC in the Middle East, in contemporary Israel, Lebanon and in the neighboring province of Cyprus. Since then, products obtained from glassblowing have become part and parcel of daily life. Though it was once looked at from a scientific point of view due to the fact it is a scientific invention, glassblowing has over the years emerged as an art form
There are two major glass blowing techniques namely; lampworking and off-hand. The off-hand technique basically works the glass on the end of a hollow tube, while the lampworking technique is achieved by use of an oxy-fuel torch. The lampworking technique is majorly used for smaller glass objects and involves manipulation of molten glass over a small torch. This article shall dig deep into each of these techniques with an aim of providing an in depth analysis into how each of them is achieved.
Glass Blowing Steps Using The Off-hand Technique
- Gather molten glass- Molten glass can be gathered from the furnace with the aid of a hollow steel-tube or blow pipe. The average temperature of this molten glass while in the furnace should stand at 2025-2125 degrees Fahrenheit. To ensure that the glass is gathered evenly and steadily, it requires that the steel rod be rotated continuously in the furnace.
- Marver the glass- A marver is a steel table on which the glass is shaped once it is stable. Glass shaping starts by rolling the hot glass on the marver in order to obtain a symmetrical cylinder. Once this cylinder is achieved, further rotation of the blow pipe is required in order to prevent the glass from dripping off.
- Cap- Capping involves blowing into the pipe and covering the hole using one’s thumb in order to create a positive pressure that causes the trapped air to expand inside the pipe, thereby creating a bubble. Once the bubble is created, more glass can be gathered around it depending on the desired size.
- Shape the piece into a bullet – By use of a soaked newspaper, shape the parison into a bullet, then re-heat it in the glory-hole, keeping the rod rotating at all times.
- Define your shape-Define your desired shape by rolling the piece on the marver while your assistant blows air into the glass through the pipe.
- Cut in a jack line-Once a shape is defined, create score lines in the piece’s neck using jacks [large tongs], by keeping the neck length less than or equal to the diameter of the blow pipe.
- Open the glass and finish the piece-This involves transferring the piece to a different rod called punty.
- Cool and trim-While placing your thumb over the hole through which you were blowing,carefully dip the pipe into a bucket of water. Re-heat the glass inside the glory-hole and then trim the lip using shears.
- Crack your piece off the pipe-Use a wooden block to forcefully knock the pipe so that the piece drops off its end.
- Anneal- Carefully carry the piece over to the annealer where it should cool off overnight.
Glass Blowing Steps Using The Lampworking Technique
- Turn on the torch-The recommended torches here are the oxygen or the propane fed ones.
- Heat the mandrel-Slowly heat up the mandrel in the blow-torch. A ceramic-coated stainless steel mandrel is preferable owing to the ability of this coating to keep the molten glass from sticking to the mandrel.
- Flash the glass through the flame tip- In order to prime the glass, it should be flashed through the flame tip for about 30 seconds. This is especially necessary in order to prevent the glass from going into shock and shattering, instead of molting up.
- Bring the glass closer to the heart of the flame-The glass should be held in the flame until it develops a nice orange ball, and it should be rotated as well to maintain its round shape.
- Attach the molten tip to the mandrel- Place the glass onto the mandrel and wrap the mandrel away from your body until you have full coverage of it, then sever the glass rod from the mandrel using the torch flame.
- Introduce the mandrel with the bead back into the flame- While rotating to prevent the slipping down of the glass, bring back the mandrel with the glass bead back into the flame, and add another color to the existing beard if desired.
- Shape the mandrel- Take the mandrel from the flame and shape as desired using a graphite paddle. The paddle can also be used to create square shapes, better edges and even out the contours of a curve.
- Cool and anneal the mandrel- Allow the mandrel to cool for a bit and then carefully transfer it to the annealer. Remember to keep rotating to maintain the shape.
Glass blowing is indeed a form of art that requires skill and diligence. Becoming a skilled gaffer therefore requires sacrifice, but should not be hard at all, given the useful and practical glass blowing techniques described above.
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