April 17, 2014

Glass Blowing

Though I direct most of my crafting energy towards knitting, I insist on keeping this a craft blog because I am always open to trying new crafts. Two years ago, I had the opportunity to learn the elementary basics of glassblowing during a weekend workshop at Palo Alto High School with my Girl Scout troop. It was cooler than 2075°F and a great experience. 

As a species, we have been melting and shaping glass for about 5,000 years, but only blowing it for about 2,000. 

The glass is stored in a crucible, or furnace, that is heated at 2075°F, which is unbelievably hot. We all had to wear long sleeves and sunglasses to make sure we wouldn't get burned or damage our eyes. Working in such extreme temperatures is also very exhausting, so professional glass blowers tend to have short, intense days to maintain their quality work. 

The Process

First, glass is gathered from the crucible and wrapped around a blowpipe. The heat of the crucible was so extreme that I never was even remotely comfortable with gathering. Glass at this temperature is bright orange, and easily can be molded into different shapes.

Then, as beginners, we practiced rolling the glass on a marver. 

Rolling a small bit of glass on a marver
When the glass gets too cold (under 900°F), the glass is reheated in a glory hole. Glory holes are smaller furnaces heated to a temperature a few hundred degrees cooler than the crucible and are much less intensely hot. You know the glass needs to be reheated when it changes from an orange color to a yellow or yellow-white and it becomes much less workable. When reheating, you also have to remember to rotate the blowpipes to keep the glass on it; molten glass responds acutely well to the force of gravity. 


Glory hole
When you are actually making a piece, it is fun to color the glass instead of have everything be clear. The available colors are all workable with the type of glass we were using--they had to have the right coefficient of expansion so the colors wouldn't break apart after annealing! Most the the colors look different on the glass than in their raw form.

We take the glass on the blowpipe and rotate the glass around the trays for the glass to pick up the tiny shards. We try to blend it more by rolling it on the marver, and heat it, too. 

Available colors for glass.
After we got some of the basics figured out, our first project was to make a paperweight of solid glass. We gathered some glass, rolled it into a ball as best we could, and gave it color. We used wet wooden blocks to help shape the general piece, and jacks (not pictured) to add smaller detail. For some extra pizzazz, we gathered a small amount of glass on a punti, or a small blowpipe, added a new color, and wrapped it around the paperweight to make a spiral. 

Dragging glass around paperweight in spiral pattern.
Then we got the jacks wet, and put them around the base of the piece to remove it from the pipe. It was transferred to the third furnace, the annealer, which slowly cooled the glass down for several hours (it's kind of like a ceramics kiln). 
Removing the paperweight to transport to the annealer for the night.
The next project we worked on was a glass flower. First we got a ball of glass colored and shaped. Then we used to jacks to pull parts of the glass apart to look like petals, and then we somehow pull the majority of the piece away from the blowpipe in a spiral pattern to make the stem (completed pieces shown below).

The next day, we finally got to start learning how to actually blow! We gathered some glass like usual, then learned to blow while rotating it on the marver. Blowing glass is harder than trying to blow even the most stubborn balloon, but just like balloons, once you get started, it becomes a little easier to continue the bubble. 


Getting the bubble started.

Once we get the right shape, we add color.



Then we move to the bench to shape the glass into a cylindrical shape to make a cup. I also added a contrasting color spiral. We then transfer the glass from the main blowpipe to a punti. There we widen the hole we made from the bubble with jacks until it actually starts to look like a cup! Then we get the base wet with the jacks and plop it off to cool down in the annealer. 


Widening the bubble with jacks.
And that's the basic process of what we did!

For a more detailed description of the process and some video footage, too, here is a video my Girl Scout leader made of our troop during this workshop! 


The Finished Products

Glass Paperweight, April 2012.
The base colors are orange and blue, and the spiral is in yellow.
The bubbles are technically mistakes and juvenile, but I was just glad to make something that didn't explode in the annealer.

Glass Poppy, April 2012.


Glass Pansy, April 2012.


Yellow and Purple Glass Cup, April 2012.


Pink Speckled Cup, April 2012.
I hope you enjoyed learning about some glassblowing basics. Check in next week for my most recent glass adventure making glass beads with torches! :)

I also recently started publishing some of my patterns on Ravelry. You can also find printable versions under the "Patterns" tab.

Happy Crafting!!
--Elizabeth

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