The fragile state of scientific glassblowing
The spaghetti junction of glass tubing bubbling with noxious liquids and gases would look perfectly at home in Frankenstein’s laboratory. But I am standing in the chemistry labs at Imperial College London, and my companion is no mad scientist. He’s not even that into chemistry – his heart is in the glass.
Stephen Ramsey is a lab technician, but of a special kind. When a chemist needs a novel reactor vessel for an experiment, Ramsey heads to his workshop and fires up his precision flamethrower. Starting with a metre-long cylinder of glass, he heats it until it begins to soften. Twirling it quickly and deftly, he blows into it, forming it.
What emerges can be anything from a delicate vial to the thin, snaking tubes of specialised vacuum pumps. Atop a cabinet in Ramsey’s office is a galloping horse he once blew out of glass. But with lab budgets under pressure worldwide, there are few scientific glassblowers like him left. Can chemistry cope without them?
Glass is the reactor material par excellence. The borosilicate glass that forms most chemical vessels is inert and hugely durable, so you can heat, cool and react the brews within knowing the glass won’t explode, deform or interfere with the reaction. And you can see what the chemicals are up to, especially useful for spotting one of those characteristic colour changes that set chemists’ pulses racing.
Chemical glass was itself something of a left-field discovery. A century or so ago US railway companies started to introduce electric lamps in railway signals. But they faced an unexpected problem: on cold nights, the sudden temperature change when a light was switched on shattered the surrounding glass. Chemists had already been experimenting with new types of glass infused with small amounts of additive, and discovered that adding a pinch of boron could improve the material’s heat resistance. It was a chemist at the Corning glass company, W. C. Taylor, who found the solution, concocting a borosilicate recipe that retained its size and shape at a far wider range of temperatures.
Pyrex cookware, introduced in 1915, is perhaps the most famous offspring of this revolution. But the effects reached furthest in the chemistry lab – making the professional glassblower a linchpin of the discipline.
The Frenchman Henri Narcisse Vigreux was an early master. The now ubiquitous Vigreux reflux condenser is formed of two concentric cylinders of glass. Water flowing through the outer tube cools a gas whipping through the inner tube, allowing it to liquefy. Vigreux’s genius lay in making the tubes’ inner surfaces delicately and intricately wrinkled, to maximise the contact area for cooling.
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Photo credit: Imperial College London