Hot glass: curiosity
Aug. 7th, 2012 06:13 pm![[personal profile]](https://www.dreamwidth.org/img/silk/identity/user.png){kind=small}
magidSunday I took a one-day intro to hot glass class at Artisan's Asylum. It was tons of fun.
We started with making single-color beads, which gave us the chance to turn on the flames (regulating the fuel and the oxygen to get the appropriate mix/heat), melt glass (which comes in long thin cylinders (about pencil width, maybe a foot or a bit more in length) into a molten blob called a gather, then turn it onto a stick called a mandrel, which is coated at one end with some kind of ceramic so the glass won't stick to it as it cools. It was interesting to see how hot glass acts similar to hot honey, actually. Because it's so affected by gravity when molten, it meant rotating the glass while held horizontally, then doing the same thing when the glass was on the mandrel. It felt like a lot to juggle at first, both hands rotating horizontal pieces, keeping things moving, moving the glass into and out of the heat to get it hot enough to flow, then cool enough not to just drip. Once the bead was on the mandrel (they were color coated at the other end with little blobs of glass, so each student's work was distinguishable), first I had to keep twirling it to get it to a good spherical shape, sometimes taking it out of the heat to use gravity to compensate for a bulge on one side or the other, then do a last pass through the upper (cooler) part of the flame to make sure it was hot enough to put into the kiln. A call of "hot glass!" as anyone moved things from the table to the kiln, especially since the aisles weren't wide. There were mandrel rests already set up in the hot (900 F ish) kiln, so it was a matter of lifting the little door, resting the mandrel, leaving the end hanging out the bottom of the door once it closed. I managed not to actually burn myself over the day, but putting things in the kiln a bunch of times meant one part of my index finger was feeling tender at the end of class just because it kept being exposed to the heat, however briefly.
I made a couple of beads, trying both transparent and opaque glass; transparent is harder, so it has a higher melting temperature, while the opaques are softer (and the instructors talked about which particular colors were more or less soft within each band of color, too). I don't think I got a good sense of this, since I was still juggling so many other technical details, though perhaps it will become relevant when (hopefully not if!) I try this again. Other than that one time with opaque glass, though, I stuck with transparent, since that's somehow much more the essence of glass to me (though I could see using it for contrast). One cool moment: I was working in completely transparent glass (working on loops), and realized that one of the neat things about clear is that the light of the molten gather reflects down the rest of the still-solid glass, lighting it from the inside. So very cool.
Once we'd all done a few beads, we moved away from mandrel projects to ones just using glass, along with tweezers and (dang, I don't remember the right term. It looks like a small black square with a handle, and the material of the square is such that hot glass slides on it; used for putting flat sides on things, because glass wants to be spherical(ish)). The teacher heated a rod of glass and talked through the process of making a swan. She made it look so easy! Melt a bigger gather than for a bead, flatten the underside, make a tail, then pull out the other side into a neck, reheat just enough to pull out a beak, and done! Alas, I am not (yet?) a swan-maker. Mine, well... they all had bodies. Two had necks. None had beaks (don't even mention the possibility of wings, which were the next step if someone made a lovely one). I tried three, and nothing pretty happened, though the other students seemed to make some very passable ones. Ah, well.
The next thing we made were heart pendants. Heat another big gather, then hold the stick of glass vertically out of the flame so the gather became more of a teardrop. Once it had, but was still red hot, use scissors to cut the glass partway up (such a strange sensation, and requiring more force than I'd expected for something that looked to be so molten-liquid). Put it back in the heat to allow the sharp points of either side of the cut to round into the lobes of the heart, then start heating another stick of glass while keeping the heart in shape. Once there was a gather on the second stick of glass (of the same or a contrasting color) and one of the top of the lobes of the heart was also hot, stick them together (hot to hot makes a strong lasting bond, while hot to not-that-hot (ie, not red hot, but still hot enough to hurt if actually touching the thing :-) makes a weak or impermanent bond (useful when in the middle of making things, rather than for the finished product). Pull them out of the heat, and then wait until a magical moment when it was cooler but not too cool to pull out a thinner piece to loop down to the heart again. Rejoin, then heat near the join to get the rest of that second stick of glass off, while not heating the loop at all, which would collapse it. Take out of the heat, then hold the heart by the loop with the tweezers. Use a similar process to get the original stick of glass off the bottom of the heart, and gravity and and possibly using a tool to make a point that was good enough (for whatever value of good enough). Put back into the cooler end of the heat to make sure it was warm enough, then use the tweezers to carry to the kiln.
I ended up practicing loops for a while, since I didn't have a good handle (ahem!) on them, and while I think I got a bit better, I can see how I could use a lot more work on mine. Oh, the TA did a demo of how to make loops slightly differently, doing a strong attach of a gather onto the pendant, then stretching out a line once it had cooled enough (slowly, slowly, but not too slow.... I think it takes a lot more practice to get a good feel for how cool and how slow/fast), using the scissors to cut the line when it was long enough (another thing it takes experience to learn), and letting gravity slowly bend it back to the original piece. Neat to watch, but I didn't attempt it all day.
The TA gave a demo of making a marble, which includes first making twirls of colors to put in the marble. He layered a couple of colors together, with clear between them and on every side of the gather he made into a rectangular shape. He took number of passes to heat the whole up, since it's nontrivial to get the inside of such a big piece hot enough without the outside being too hot. Interestingly, each time he'd take the gather out of the flame, he'd blow on the outside to cool it just a bit, then put it back in to get more heat moving inward. He attached another piece of glass to the other side of the rectangle, and then pulled out each end while twirling. He stopped when he couldn't get his hands farther apart; had another person taken the other end, it could have been longer. He snipped off the long thin middle ribbon of color, and started on the marble itself. He made a gather of clear glass, and used the middle of three hemispherical molds (on one piece) to start forming it. However, he had a strong bond with the original glass, so there were a series of weak-bonded (drat, another technical term) pieces of glass so he could get the current glass off, then heat that region. And he kept shaping it spherically, too. At one point he cooled the outside some, leaving the inside hot, and used the smallest mold to move the molten glass around inside. Towards the end, he put the ribbon of twirled colors around the marble, and melted into the sphere. (I'm sure I'm leaving out some steps; it's an involved process.) A few students attempted marbles; I didn't, because I wanted to try other things.
The teacher showed us some leaf molds, one basic one and a few that were more involved; her preference is to show the basics so students can do whatever, even with minimal tools. I was intrigued by leaves, and though the rounded leaves were pretty, said something about oak leaves (thinking about The War for the Oaks (Emma Bull)). I said it as a throwaway, but the teacher pointed out that I could, in fact, make oak leaves. So instead of just heating a gather, using the mold, pulling out a point on one end and a loop on the other, I also heated places along each edge, cut them, then used tweezers to make the cuts more like the notches in oak leaves. Not perfect oak leaves, but something in the ball park, anyway.
We had some time left. I made some more beads on mandrels (marking them with my color first), this time trying clear ones with blue dots on them. Well, dots or extrusions, in my case. I said something about how irregular they were, and the teacher suggested counting out loud to get the timing of each one the same, which helped some. Also, her saying that it's difficult to do by anyone, so not having it perfect my first day was just fine helped too :-). And I tried another heart at the end, to see whether I'd gotten any better at using the scissors and making loops. (Short answer: maybe, but not clearly so.)
There were five students in the class, and a TA in addition to the teacher, so there was lots of help when the things the teacher showed didn't work quite the same way in our newbie hands. All the things we made except the swans (and my practice loops) ended up in the kiln, which would cool slowly but not too slowly from 900 F to room temp the next day, which meant we could pick up our things later Monday, or sometime after that. Unfortunately for me, I can't make it in until Sunday, so I have no pictures to share yet of finished things, but there will likely be a photo post coming next week :-).
We started with making single-color beads, which gave us the chance to turn on the flames (regulating the fuel and the oxygen to get the appropriate mix/heat), melt glass (which comes in long thin cylinders (about pencil width, maybe a foot or a bit more in length) into a molten blob called a gather, then turn it onto a stick called a mandrel, which is coated at one end with some kind of ceramic so the glass won't stick to it as it cools. It was interesting to see how hot glass acts similar to hot honey, actually. Because it's so affected by gravity when molten, it meant rotating the glass while held horizontally, then doing the same thing when the glass was on the mandrel. It felt like a lot to juggle at first, both hands rotating horizontal pieces, keeping things moving, moving the glass into and out of the heat to get it hot enough to flow, then cool enough not to just drip. Once the bead was on the mandrel (they were color coated at the other end with little blobs of glass, so each student's work was distinguishable), first I had to keep twirling it to get it to a good spherical shape, sometimes taking it out of the heat to use gravity to compensate for a bulge on one side or the other, then do a last pass through the upper (cooler) part of the flame to make sure it was hot enough to put into the kiln. A call of "hot glass!" as anyone moved things from the table to the kiln, especially since the aisles weren't wide. There were mandrel rests already set up in the hot (900 F ish) kiln, so it was a matter of lifting the little door, resting the mandrel, leaving the end hanging out the bottom of the door once it closed. I managed not to actually burn myself over the day, but putting things in the kiln a bunch of times meant one part of my index finger was feeling tender at the end of class just because it kept being exposed to the heat, however briefly.
I made a couple of beads, trying both transparent and opaque glass; transparent is harder, so it has a higher melting temperature, while the opaques are softer (and the instructors talked about which particular colors were more or less soft within each band of color, too). I don't think I got a good sense of this, since I was still juggling so many other technical details, though perhaps it will become relevant when (hopefully not if!) I try this again. Other than that one time with opaque glass, though, I stuck with transparent, since that's somehow much more the essence of glass to me (though I could see using it for contrast). One cool moment: I was working in completely transparent glass (working on loops), and realized that one of the neat things about clear is that the light of the molten gather reflects down the rest of the still-solid glass, lighting it from the inside. So very cool.
Once we'd all done a few beads, we moved away from mandrel projects to ones just using glass, along with tweezers and (dang, I don't remember the right term. It looks like a small black square with a handle, and the material of the square is such that hot glass slides on it; used for putting flat sides on things, because glass wants to be spherical(ish)). The teacher heated a rod of glass and talked through the process of making a swan. She made it look so easy! Melt a bigger gather than for a bead, flatten the underside, make a tail, then pull out the other side into a neck, reheat just enough to pull out a beak, and done! Alas, I am not (yet?) a swan-maker. Mine, well... they all had bodies. Two had necks. None had beaks (don't even mention the possibility of wings, which were the next step if someone made a lovely one). I tried three, and nothing pretty happened, though the other students seemed to make some very passable ones. Ah, well.
The next thing we made were heart pendants. Heat another big gather, then hold the stick of glass vertically out of the flame so the gather became more of a teardrop. Once it had, but was still red hot, use scissors to cut the glass partway up (such a strange sensation, and requiring more force than I'd expected for something that looked to be so molten-liquid). Put it back in the heat to allow the sharp points of either side of the cut to round into the lobes of the heart, then start heating another stick of glass while keeping the heart in shape. Once there was a gather on the second stick of glass (of the same or a contrasting color) and one of the top of the lobes of the heart was also hot, stick them together (hot to hot makes a strong lasting bond, while hot to not-that-hot (ie, not red hot, but still hot enough to hurt if actually touching the thing :-) makes a weak or impermanent bond (useful when in the middle of making things, rather than for the finished product). Pull them out of the heat, and then wait until a magical moment when it was cooler but not too cool to pull out a thinner piece to loop down to the heart again. Rejoin, then heat near the join to get the rest of that second stick of glass off, while not heating the loop at all, which would collapse it. Take out of the heat, then hold the heart by the loop with the tweezers. Use a similar process to get the original stick of glass off the bottom of the heart, and gravity and and possibly using a tool to make a point that was good enough (for whatever value of good enough). Put back into the cooler end of the heat to make sure it was warm enough, then use the tweezers to carry to the kiln.
I ended up practicing loops for a while, since I didn't have a good handle (ahem!) on them, and while I think I got a bit better, I can see how I could use a lot more work on mine. Oh, the TA did a demo of how to make loops slightly differently, doing a strong attach of a gather onto the pendant, then stretching out a line once it had cooled enough (slowly, slowly, but not too slow.... I think it takes a lot more practice to get a good feel for how cool and how slow/fast), using the scissors to cut the line when it was long enough (another thing it takes experience to learn), and letting gravity slowly bend it back to the original piece. Neat to watch, but I didn't attempt it all day.
The TA gave a demo of making a marble, which includes first making twirls of colors to put in the marble. He layered a couple of colors together, with clear between them and on every side of the gather he made into a rectangular shape. He took number of passes to heat the whole up, since it's nontrivial to get the inside of such a big piece hot enough without the outside being too hot. Interestingly, each time he'd take the gather out of the flame, he'd blow on the outside to cool it just a bit, then put it back in to get more heat moving inward. He attached another piece of glass to the other side of the rectangle, and then pulled out each end while twirling. He stopped when he couldn't get his hands farther apart; had another person taken the other end, it could have been longer. He snipped off the long thin middle ribbon of color, and started on the marble itself. He made a gather of clear glass, and used the middle of three hemispherical molds (on one piece) to start forming it. However, he had a strong bond with the original glass, so there were a series of weak-bonded (drat, another technical term) pieces of glass so he could get the current glass off, then heat that region. And he kept shaping it spherically, too. At one point he cooled the outside some, leaving the inside hot, and used the smallest mold to move the molten glass around inside. Towards the end, he put the ribbon of twirled colors around the marble, and melted into the sphere. (I'm sure I'm leaving out some steps; it's an involved process.) A few students attempted marbles; I didn't, because I wanted to try other things.
The teacher showed us some leaf molds, one basic one and a few that were more involved; her preference is to show the basics so students can do whatever, even with minimal tools. I was intrigued by leaves, and though the rounded leaves were pretty, said something about oak leaves (thinking about The War for the Oaks (Emma Bull)). I said it as a throwaway, but the teacher pointed out that I could, in fact, make oak leaves. So instead of just heating a gather, using the mold, pulling out a point on one end and a loop on the other, I also heated places along each edge, cut them, then used tweezers to make the cuts more like the notches in oak leaves. Not perfect oak leaves, but something in the ball park, anyway.
We had some time left. I made some more beads on mandrels (marking them with my color first), this time trying clear ones with blue dots on them. Well, dots or extrusions, in my case. I said something about how irregular they were, and the teacher suggested counting out loud to get the timing of each one the same, which helped some. Also, her saying that it's difficult to do by anyone, so not having it perfect my first day was just fine helped too :-). And I tried another heart at the end, to see whether I'd gotten any better at using the scissors and making loops. (Short answer: maybe, but not clearly so.)
There were five students in the class, and a TA in addition to the teacher, so there was lots of help when the things the teacher showed didn't work quite the same way in our newbie hands. All the things we made except the swans (and my practice loops) ended up in the kiln, which would cool slowly but not too slowly from 900 F to room temp the next day, which meant we could pick up our things later Monday, or sometime after that. Unfortunately for me, I can't make it in until Sunday, so I have no pictures to share yet of finished things, but there will likely be a photo post coming next week :-).