How to Blow Glass
Gather the molten glass., Marver (shape) your glass., Cap., Gather again., Shape your piece into a bullet., Define your shape., Cut in a Jack line., Open the glass and finish the piece., Cool your pipe., Trim the lip., Crack your piece off of the...
Step-by-Step Guide
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Step 1: Gather the molten glass.
With a hollow steel tube, or blowpipe, gather the glass from the furnace (the oven where molten glass is kept).
The molten glass in the furnace should be about 2,025 to 2,125 °F (1,107 to 1,163 °C).
A simple but accurate analogy is turning caramel onto an apple.
Think of your steel rod as the apple and the furnace as the pot of caramel.
Just as you slowly rotate the apple in the hot caramel, gathering glass requires continuous rotation of your steel rod in the furnace, in order to gather the glass steadily and evenly. -
Step 2: Marver (shape) your glass.
Once the glass is stable, carry it to a steel table, called a marver, and begin shaping it.
Glass shaping begins with rolling the hot glass on a marver.
It is important to make sure that your cylinder is symmetrical.
Once you’ve achieved your cylinder, continue to rotate the blowpipe, to prevent the glass from dripping off.
The marver will suck a lot of heat from the molten glass because the surfaces of the two materials actually touch as the glass rolls across the marver.
If the sides of the glass get too thin, chill them by rolling them on the marver.
If the bottom of the glass gets too thick, introduce the glass back into the glory hole (the oven that reheats the glass to keep it malleable) and concentrate the heat on the bottom of the glass.
Turn constantly as you heat the glass. , Blow into the pipe then cover the hole with your thumb.
The positive pressure will cause the trapped air to expand inside the pipe, which in turn will create a bubble.
This first gather and bubble is called the parison.
Once you have an even-walled bubble, you may again marver and gather more glass.
Remember to rotate the rod continuously as you move from the marver to the furnace and glory hole. , Collect more glass around your bubble.
The number of gathers you make depends upon how big you would like your piece to be — bigger pieces require more gathers.
If you wanted a bit of color, now might be a good time to introduce it onto your cooler post. , When you are done with your gathers, use a soaked newspaper and with it shape your parison into a bullet.
Then reheat it in the glory hole.
Remember to keep the rod rotating at all times! , Shape your piece by rolling it on the marver, while an assistant blows air through the pipe and into the glass.
If you want the bubble to move down the glass, marver the sides and not the bottom.
With the sides cooler, the bubble will push the bottom down even further when you blow on it.
If you want the bubble to move out the glass so that the sides expand, marver the bottom and not the sides.
With the bottom cooler, the bubble will push the sides out even further when you blow on it. , Once your piece is shaped you cut in, or create score lines in the piece’s neck with large tongs known as jacks.
The neck should be equal to or less than the diameter of your blow-pipe.
Keep rotating your pipe! , This requires you to transfer your piece to another rod called a punty.
It’s one of the trickier parts of glass blowing.
A little trade secret, however makes it a whole lot easier.
Find a small tool (a file is best) and dip it in water.
Carefully etch a line around the neck.
This weakens the glass and makes it brittle.
It then easily separates from the original pipe. , Place your thumb over the hole though which you were blowing and then carefully dip the pipe into a bucket of water, all the while keeping your thumb over the blow hole to stop the water from shooting up the pipe and ruining it. , Reheat the glass in the glory hole and trim the lip with shears. , Using a wooden block, tap the pipe forcefully, your piece should drop off the end of the pipe. , Carefully carry it over to the annealer (an oven that cools glass at a controlled rate) and leave it to cool overnight. -
Step 3: Gather again.
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Step 4: Shape your piece into a bullet.
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Step 5: Define your shape.
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Step 6: Cut in a Jack line.
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Step 7: Open the glass and finish the piece.
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Step 8: Cool your pipe.
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Step 9: Trim the lip.
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Step 10: Crack your piece off of the pipe.
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Step 11: Anneal in order to cool off.
Detailed Guide
With a hollow steel tube, or blowpipe, gather the glass from the furnace (the oven where molten glass is kept).
The molten glass in the furnace should be about 2,025 to 2,125 °F (1,107 to 1,163 °C).
A simple but accurate analogy is turning caramel onto an apple.
Think of your steel rod as the apple and the furnace as the pot of caramel.
Just as you slowly rotate the apple in the hot caramel, gathering glass requires continuous rotation of your steel rod in the furnace, in order to gather the glass steadily and evenly.
Once the glass is stable, carry it to a steel table, called a marver, and begin shaping it.
Glass shaping begins with rolling the hot glass on a marver.
It is important to make sure that your cylinder is symmetrical.
Once you’ve achieved your cylinder, continue to rotate the blowpipe, to prevent the glass from dripping off.
The marver will suck a lot of heat from the molten glass because the surfaces of the two materials actually touch as the glass rolls across the marver.
If the sides of the glass get too thin, chill them by rolling them on the marver.
If the bottom of the glass gets too thick, introduce the glass back into the glory hole (the oven that reheats the glass to keep it malleable) and concentrate the heat on the bottom of the glass.
Turn constantly as you heat the glass. , Blow into the pipe then cover the hole with your thumb.
The positive pressure will cause the trapped air to expand inside the pipe, which in turn will create a bubble.
This first gather and bubble is called the parison.
Once you have an even-walled bubble, you may again marver and gather more glass.
Remember to rotate the rod continuously as you move from the marver to the furnace and glory hole. , Collect more glass around your bubble.
The number of gathers you make depends upon how big you would like your piece to be — bigger pieces require more gathers.
If you wanted a bit of color, now might be a good time to introduce it onto your cooler post. , When you are done with your gathers, use a soaked newspaper and with it shape your parison into a bullet.
Then reheat it in the glory hole.
Remember to keep the rod rotating at all times! , Shape your piece by rolling it on the marver, while an assistant blows air through the pipe and into the glass.
If you want the bubble to move down the glass, marver the sides and not the bottom.
With the sides cooler, the bubble will push the bottom down even further when you blow on it.
If you want the bubble to move out the glass so that the sides expand, marver the bottom and not the sides.
With the bottom cooler, the bubble will push the sides out even further when you blow on it. , Once your piece is shaped you cut in, or create score lines in the piece’s neck with large tongs known as jacks.
The neck should be equal to or less than the diameter of your blow-pipe.
Keep rotating your pipe! , This requires you to transfer your piece to another rod called a punty.
It’s one of the trickier parts of glass blowing.
A little trade secret, however makes it a whole lot easier.
Find a small tool (a file is best) and dip it in water.
Carefully etch a line around the neck.
This weakens the glass and makes it brittle.
It then easily separates from the original pipe. , Place your thumb over the hole though which you were blowing and then carefully dip the pipe into a bucket of water, all the while keeping your thumb over the blow hole to stop the water from shooting up the pipe and ruining it. , Reheat the glass in the glory hole and trim the lip with shears. , Using a wooden block, tap the pipe forcefully, your piece should drop off the end of the pipe. , Carefully carry it over to the annealer (an oven that cools glass at a controlled rate) and leave it to cool overnight.
About the Author
Betty Hughes
Specializes in breaking down complex home improvement topics into simple steps.
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