University Place

cc >> Welcome, everyone, to Wednesday Nite at the Lab. I'm Tom Zinnen. I work at the UW Madison Biotechnology Center. I also work for UW Extension Cooperative Extension, and on behalf of those folks and our other co-organizers, Wisconsin Public Television, the Wisconsin Alumni Association, and the UW-Madison Science Alliance, thanks again for coming to Wednesday Nite at the Lab. We do this every Wednesday night, 50 times a year. Tonight, we have a remarkable presentation by Tracy Drier. He's the research glassblower from the Department of Chemistry. He was born in Holland, Michigan, went to Western Michigan University, became a paper engineer, worked in Appleton, Wisconsin, for a while there, then he shifted careers, went to Salem Community College in the southern part of New Jersey to learn glassblowing. He's been here for the last 14 years as a glassblower. This is the Wisconsin fire wagon, as he likes to call it. Flame, heat, and great insight. Please join me in welcoming Tracy Drier to Wednesday Nite at the Lab.

APPLAUSE

>> Thank you. So, as Tom said, I work for the chemistry department. I am the glassblower for the department, and I work alone in my shop, and so to have a big crowd like this is very exciting for me.

LAUGHTER

And here we go. So what I wanted to talk about today was a few things. I'll tell you a little bit about glass, tell you a little bit about scientific glass specifically, and then do some demonstrations with the fire wagon. That's this piece right here. So we'll get started.

The big question is

what is glass? And the short answer is that it's not a simple question. It's an amorphous solid, and what that means is that it has properties of both solids and liquids. There are people here at the university in the chemistry department and in material science, that's all they do is they study glass and they try and answer these kinds of questions. When I first started, they were calling it a supercooled liquid. And so this whole definition of glass, it's evolving. And it's, like I said, it's very complicated. And according, for us, for every day use, it's essentially a solid, but it doesn't have a crystal structure like a normal solid does. And that's what gives it the property, that's why it has also properties of a liquid. If we talk about natural glasses first, we have obsidian, coming from volcanoes. These were probably the first practical tools made out of glass for tools and weapons. You also have fulgurite, which is when lightning strikes sand. You get these little tubes of quartz glass, pure sand, and they run like little roots from the source of the impact, the strike. And then there's also tektites, which are a glass that comes from meteor impacts on the Earth. If we go into the early glassmaking processes, paste forming is probably one of the first real processes with glass. And they made pieces with it, but probably more common was used to coat ceramics. Just a glass layer over ceramics. Then you get into core forming where you would take a rod and then put grass and dung and form it into a shape, and then either dip it into molten glass or down below you wrap a solid piece of rod around that form. After the piece has cooled, you take the handle off, and then you dig out the inside, creating the vessel. And then, after that, the blow pipe entered the scene, on the far end here, and that allowed people to dip directly into the molten glass, and then free-form blow or else use a mold and then get uniform shapes. So one of the most interesting things about glass is the fact that it flows. Like I was saying, it doesn't have a distinct melting point. It has a range where it's soft, and so in that case, it's a lot like honey. You have honey in the refrigerator, it will come out some time but not any time soon.

LAUGHTER

The big question is

You take that jar, that same jar, and you put it in the microwave, you raise the temperature up, and now it will come right out.

finger snap

The big question is

No problem. And that's a lot like glass. And that's what makes it such an interesting material to work with because it's tricky that way. We also have stresses in the glass. As the glass cools, you have tension and compression being put into the glass as it's cooling. And the compression makes the glass stronger, and tension is actually very fragile and is what causes the glass to break. Another very interesting phenomenon with glass is that it's a very good insulator. You'll see me coming up here a little bit later, working very close in the fire with the glass, and while I can feel the heat from the fire, the heat isn't transferring down through the glass like it would with metal. And so it's a very good insulator, and, in fact, you might recognize these as insulating the high electricity wire from the wooden telephone poles. So that's when the glass is cold, but then once it gets molten, it actually conducts electricity. So you can use that to, for example, melt glass. Once you use gas to soften up your glass, you can use electricity then to keep it molten. So we have three basic ways that we can manipulate glass. This, I actually saw this here. No. So, this is Audrey Handler's glass furnace and glory hole. Audrey is an alumni from UW. She was one of the first glass students under Harvey Littleton, and she's still right here local in Verona. And this is her shop. And so you have a big pot of molten glass on the left-hand side, and then you reheat with that glory hole on the, excuse me, on the left, and on the right is the glory hole. And so the properties for this kind of glassblowing is you're coming out and you're working at it, working with it, at a bench so it has to stay hot and molten for quite a long time. Those properties that give it that length of use also make it incredibly shocky. When it heats and when it cools, it wants to break. So you have to really pay attention after you've made a piece, you put it in an oven and you heat the entire thing down slowly to prevent it from breaking. Then we have torch work. And you can see kind of with these photos the fire is much more focused and intense than with that general furnace and glory hole. And that requires a bit of different properties of the glass. We'll get to properties here in a little bit. Here's a piece that would be, for example, made with a torch. The third type of glassworking is with a kiln. Up here, we have the kiln, and this, again, is kind of a general overall heat, and you're not able to get in there and manipulate the glass as you are with the other two forms of glassblowing. So you kind of set everything up in an open oven, shut the lid, turn on the power, and kind of peek at it. And then when it's done, so what we did here was we put these little tubes on the flat sheet, and they just sealed right down onto the sheet. And in this particular way, we wouldn't have been able to do that with a torch. There's so much stress that would be built up into that piece that it wouldn't get very far before it broke. And so what they did with this was they put it on a stirring plate in a very crowded glove box, and they were able to stir a lot of little vials without them kind of falling all over the place. There's another type of glass forming that doesn't involve heat, and that's called cold working. And that's something like this where you're using saws and drills and engraving and doing some type of secondary decoration. So here's a picture of my shop. We have a torch set up, and then there's also some lathes. And, in this case, the headstock, unlike a machine lathe where only the headstock moves, we have both the headstock and the tailstock that move. And that allows you to work larger diameter tubing, for example. And then there's also a cold working area for cutting and sanding, polishing and drilling. And if we start looking at scientific glass and what the unique needs are, they are that they have to withstand changes in temperature. And one of the things, actually I need to back up a little bit. I need to talk about glass itself. The main piece in glass is sand. And while we can take this and melt it, heat it up, it takes a lot of energy to form it into glass. And it's not actually practical, if we're talking about windows and bottles for juice. It just takes too much energy to melt it. And so what we do then is we add a flux. And in this case, it's soda, soda ash. We add soda ash to it, which will lower the melting temperature of the glass. So now we can melt it at a lower temperature, but, unfortunately, it will dissolve in humidity in the air. So then we add limestone, calcium carbonate, to stabilize it. And that's why sometimes you'll hear glass referred to as a soda lime glass. It's got soda and it has lime in it. And probably 90% of the glass in the world is some type of a soda lime glass. They can add things, for example, to make it blue, make it green, give it some other properties. For example, bottles. They want bottles to actually, because they're squirted out of a machine, when they're rolling down a conveyor belt, they don't want them sagging, so they are designed to set up fast. Unlike the glory hole and the furnace, you want that glass to stay soft for as long as you can. So it is engineered to some degree, but, for the most part, it's soda and lime. And back, this was, I don't exactly know the date, but there was a train disaster. They had lanterns that they used to signal the trains when they were coming around. And the heat on the lens of the lantern was such that when it started to rain, the lens broke and the lamp went out and trains collided. And so, at that point, they started working on a glass that would withstand temperature extremes like that. And that is when borosilicate glass came in to be developed. And borosilicate glass has boron, boric oxide added to it. And that gives it properties that are most useful. For example, lanterns in the rain, hot lanterns in the rain, but also in the chemistry lab. And the changes in temperature and it's clear and it has to resist chemical attack. One of the things about soda lime glass is that while it's good for holding juice, it's not actually so good for holding acids and that kind of thing. It deteriorates, and so we need to have a little stronger, more durable glass, and that is borosilicate glass. And Pyrex is one of the trade names, and that's probably one you're familiar with in your kitchen from freezer to oven safe. And that's the same glass that we use to build chemistry. But the thing with, while those are all good things, one of the differences is that with borosilicate glass we actually need a higher temperature than we would with the furnace and the glory hole. It would be possible to, you saw I did use a kiln for borosilicate, and they do actually make a furnace and a glory hole for borosilicate glass. Those are extreme in terms of temperature. It's very hard on the equipment. And so kind of practical every day kind of use, it's not for everybody. And so my raw materials, they come, and actually these slides are a little out of, so this is a slide of kind of my raw materials. Instead of, like the art department here with the big crucible full of molten glass, they can dip out and they can pull tubing all day, it's not practical to do that with borosilicate glass. Or at least on a small scale. And so it's pre-made. I get all my glass, this is a variety of different sizes. These are all hollow tubes. Along the side here we have solid glass. And they come in four- or five-foot lengths. And you just pay some money and they arrive.

LAUGHTER

The big question is

And the same with the glass components. Back 50 years ago, kind of like the golden age of glassblowing when everybody had 20 glassblowers, five of them in the shop would be in charge of making these components for everybody else to be using. And that's not the case again now. These are all standard. If you buy them from one company, you can buy them from the other company, and they're going to go together just fine. And so, again, they're like four dollars or something for one of these tapered joints. And what these are, these are kind of the connectors so that things will come apart. They can be cleaned easier. They can be interchanged. Oh, no. It's the wrong size, but if I had the right size, you could start interchanging things and taking them apart. There's valves. You have a variety of different valves, and one of the nice things about having a glassblower in the chemistry department is the students actually can just get in the elevator. If they have an idea that they're trying to achieve some objective, they can come down and not actually have to be an expert in glass, and together we can kind of go through the process of kind of designing the piece. And I can build it, then they can take it back to the lab, and then glass is actually very easy to modify. If, for example, they wanted this to be up here instead, it would be a very straightforward job to take this off and pop another hole, stick that on, relatively speaking. Compared to, you have to know a little something about glass.

LAUGHTER

The big question is

But compared to, like, metal, for example, it could be a little trickier. And the other thing I do have to say is I provide one of the support team for the chemistry department. There is also the machine shop and the electronic shop, and so just like the glass shop, it's nice to have experts who can help out the students kind of focus on doing their research and kind of have everything in-house. Yeah, I just think that's fabulous. So, this is the fire wagon. And I take this out to demonstrations like this. I go out to schools. And it's on wheels. It moves around just like a hand truck. You can take it, throw it in the back of your car. I'm going to just spin it around here. So it's kind of a self-contained piece. There's propane and there's oxygen, and they're connected up to this torch. And we turn on the propane and get it started. We have a nice yellow fire. This is not quite hot enough. This isn't even close enough to melt glass. So we slowly introduce the oxygen. We can see the color change. And so now this is a fire, maybe 2800 degrees Celsius. There's one on the top, and then there's also a bigger one on the bottom. So this is for bigger tubing. If I want to heat a nice, wide area or, for example, a bend, it'd be nice to have a nice, big fire like this. I'm going to bring my notes over here. So what I want to do now is cut some glass. Cut it, break it. And the way to cut glass, it needs two things. You need to have a flaw in the glass, and then you have to have a stress. And, like I said before, glass is very strong under compression and very weak under tension. So I have my flaw and if I pull it back this way, the backside is under compression and the outside is under tension, and so it just comes right apart very easily. Now I'm going to take something. I've introduced the flaw. Now this is quite a, it's a huge tube and it's a little off-center. So I can't really get force enough to actually make this thing go. So the first time I used a mechanical stress. You can also use thermal stress. So I introduced stress right in front of this crack, and it's going to find that flaw...

WHISTLES

The big question is

All the way around. Oh, sorry, folks.

LAUGHTER

The big question is

So that happens. Actually, that happens a lot, and there's no need to run.

LAUGHTER

The big question is

These torches just do that. But I do apologize. So what I'm going to do now, like I said, is introduce some thermal stress in front of that, and it has to be a very small fire. I don't know if you heard that. So that's how we break glass. So now probably one of the biggest questions, two big

questions

do you ever burn yourself, or do you ever cut yourself? And yes I do.

LAUGHTER

questions

Yes. Not as much as I used to, but you do. Everybody does. And, yeah, they're liars if they tell you otherwise.

LAUGHTER

questions

And then the next question is, oh, you must be used to it by now. And no.

LAUGHTER

questions

It hurts every time.

LAUGHTER

questions

Every time. It's horrible. So we try to minimize that. One of the things, as we introduce the energy into the glass, it's going to start to change color. And we can see it's starting to glow. So now we start doing things, and we actually have no idea which end is hot anymore. And that's a problem. We have a little piece of flash paper. All right. Got lucky. First time. But when you're first starting out, it's very important to have good working habits. And the biggest one is when you're working with glass, you only use one end of the glass and you always put that hot end away from you. And it's amazing when you see people just beginning. They have big nests on both ends of their glass rod. So starting with good habits early on will kind of help avoid those kind of injuries because, yeah, it isn't fun. So I also wanted to introduce this idea of the different kinds of glasses. We have the soda lime glass, and we have borosilicate glass. With the white tape, I think you can probably see which one of them is different than the others.

LAUGHTER

questions

I didn't want to lose track. So what I'm doing here is just a demonstration of the differences in the working properties of these two types of glass. They're both in the fire kind of for about the same time. I keep moving them back and forth to the front. And now if we just kind of let them go, you can see the one is a lot more viscous than the other. I don't want to make it pop again for you guys. And I don't even want to get started with the stories with these little pieces of fiber like this in terms of safety. You really need to pay attention to keep those under control because they're very dangerous. This is just a little bucket of water. One of the things that I wanted to also demonstrate was the idea of stress in glass. This idea of tension and compression. We can actually use it to our advantage with, for example, tempering. Tempered glass, our car automobile windshields are all tempered. The surround shower doors are tempered. You want those things to be stronger, and if they do break, you want them to break into tiny little pieces and not slice you like, yeah. This is just a demonstration on this idea of tempering glass. So you see me putting these glasses on. Actually, I can, if you notice, as I work the glass in the fire, it turns yellow, and that's sodium, sodium that's in the glass is going into solution and coming off and we see it as yellow. And what these glasses do is they filter out that wavelength of yellow so that I can actually see inside the fire what I'm doing. It's possible. I can do it without it, and you guys are obviously doing without it, but it's comfortable for me. It's what I do all do all day. And I just want to protect my eyes. Short-term, for example, what you guys are watching here, it's not a particular safety hazard at all. It's just you can't really see what's going on inside. So I'm going to just, this is a piece of pink glass, and I chose a piece of pink just because it's a little easier to see than clear, which is what I'll be, it's just easier to see. That's the only difference. There's a little bit of colorant in the glass when it was made. It's a borosilicate glass, just like the clear ones. So what I'm going to do is just slowly heat this up. And you'll notice that I'm always rotating it. You saw that little exercise that I did when I stopped rotating those pieces of rod and just held them straight up and down, what happened, and that's the reason you keep rotating. You always rotate. So I'm just separating these two. I'm heating them up, and as it starts to soften, I just slowly pull it apart. Separate the two pieces. I'll actually use this piece. The other thing, these are just regular metal tweezers. I'll talk a little bit about the tools that I use. But what I'm actually making is called a Bologna bottle. It's very similar to a Prince Rupert's drop, if you're familiar with those. Essentially I'm going to heat this up, and I'm going to dip it into water. And in a perfect world, it will not break. We all know how demos go.

LAUGHTER

questions

So I'm going to heat this up. And when I dip it into the water, the outside is going to contract. So that's actually going to be under compression. It kind of locks everything internally down, but it's still screaming hot inside. So it winds up putting everything inside under tension. So the outside of this glass is going to be very strong, and the inside of the glass is going to be just fine as long as there's no little flaw like we saw earlier. So we're going to just drop it into some water. And here we have the Leidenfrost effect where there's a vapor layer between the glass and the water. Getting nervous?

LAUGHTER

questions

We're going to stop right there. So it's still in one piece. I'm going to just leave that on. So I actually have these. This isn't serious wood. This is just pine wood, and these are aluminum nails. But still, I wanted to demonstrate just kind of the strength that we've introduced into this.

POUNDING

questions

This is very strong. This whole thing is under compression, and so there's not much that's going to break it from the outside. But like I said, the inside is under tension. So I have these little pieces of tungsten carbide, which is harder than glass, and you can see the size of this. It's not very big at all, and I'm not dropping it actually from very far. But when I drop it down in there, that little flaw releases all of that tension, and this is kind of the effect that you get. One thing I didn't actually talk about was the tools. And they're like caveman tools. They haven't really changed since the beginning of time. They're graphite rods, graphite paddles, and that's about it. You can get in, these can get hot, and they don't stick to glass. They look prettier than they probably did years ago, but that's about it. There hasn't been a lot of change because of the characteristics of glass. And any of those forms that I talked about earlier, the tools really have remained unchanged over the years. I'm actually very thirsty. Excuse me for that. Probably the only, in terms of scientific, I have vernier calipers, I use protractor and rulers. These are the only thing that are separating me from the same people who are doing this with colored glass and for art. Things have a lot tighter tolerances, and we're trying to achieve something specific for research. One of the other things that I will just demonstrate quickly is, so sometimes if we have a piece of tubing, a short piece of tubing like this or even, actually let's say like this. If I want to blow a bulb out of this, it's going to be almost impossible to even get close to the fire, let alone somehow plug this thing up and blow it. So one of the things that we do is it's called pulling a point. So what we're doing is this is just a piece of scrap glass. And I just, as it softens, I gather the end, and now I heat right behind it. Come out of the fire, wait for a couple of seconds to let the temperature reach equilibrium, and then pull it. And, again, I'm rotating as I pull it because I'd like to try and keep it as centered as I can. Yeah, that's nice and straight. So this is called a point. Now I can do the exact same thing on the other side. And you can kind of see what's going to happen here.

POUNDING

questions

So, again, as the piece warms up, it softens up, and I can just grab the end, heat behind it, rotating. Then as it gets warm enough, I come out of the fire, let it sit for a minute, slowly pull it apart. I'm going to now open this end. Fire polish this just to make it smooth so then I can actually blow into here, and I won't cut my lip. That's bad form on television.

LAUGHTER

questions

So then, as this cools, we'll see, wow, nice. Usually it doesn't work like that. So if it weren't straight, all I would have to do is get my little fire and just heat the shoulder and it would soften it and then I could get it on axis. So now I have this. It's open, and now I have almost that same amount of glass that I can now blow a bubble with, for example, or whatever. It would be, if I had another piece of tubing, I could seal a piece of tubing onto the end of this. There's any number of things now at this point, it's manageable But what I thought I would do is just demonstrate blowing a bulb. Heat it, rotate it, come out, let it set up a bit. And now what I can do is blow another bubble and then another bubble to combine them all together. Believe it or not, as you're rotating this, the glass that sees the front of the fire is actually hotter than the glass in back, and that's why I wait for a little bit before I blow. Otherwise it's going to blow unevenly. It looks like it's all just hot in there, but, in fact, the backside is cooler. So I wait just a little bit to let everything reach equilibrium. So now I'll heat the whole thing. And you can see it naturally wants to collapse. Actually, I'm going to open up this end. And what I can do is melt this down. It's a hollow tube at this point, but I just heat it up, and, like I said, the glass will naturally constrict and it will form itself into a piece of solid rod in between here. I don't know, probably the people directly in front of me can see, but this is a solid rod now in between these two pieces of hollow, and I can just heat it up and then take it and pop a little loop on there. Take one of my graphites. Actually, I'll just take a tweezer. Not particularly scientific, but, anyway, I wanted... Well, that's the other thing. Really, one of the beautiful things about this is regardless of whether it's artistic or scientific, the techniques are all the same. That's one of the beautiful things about, I do this at work and I also have a shop at home, and I do this at home for fun as well, as a hobby. And that's nice. So that's about all that I had, really. I'm happy to take any questions that you might have.

APPLAUSE