When Is Your Pyrex Not The Pyrex You Expect?

It’s not often that Hackaday brings you something from a cooking channel, but [I Want To Cook] has a fascinating look at Pyrex glassware that’s definitely worth watching. If you know anything about Pyrex it’s probably that it’s the glass you’ll see in laboratories and many pieces of cookware, and its special trick is that it can handle high temperatures. The video takes a look at this, and reveals that not all Pyrex is the same.

Pyrex was a Corning product from the early 20th century, and aside from its many laboratory and industrial applications has been the go-to brand for casserole dishes and much more in the kitchen ever since. It’s a borosilicate glass, which is what gives it the special properties, or at least in some cases it used to be a borosilicate glass. It seems that modern-day American Pyrex for the kitchen is instead a soda glass, which while it still makes a fine pie dish, doesn’t quite have the properties of the original.

The video explains some of the differences, as well as revealing that the American version is branded in lower case as pyrex while the European version is branded uppercase as PYREX and retains the borosilicate formulation. Frustratingly there’s no quick way to definitively tell whether a piece of lower-case pyrex is soda glass or not, because the brand switch happened before the formulation switch.

In all probability in the kitchen it makes little difference which version you own, because most users won’t give it the extreme thermal shock required to break the soda version. But some Hackaday readers do plenty of experiments pushing the limits of their glassware, so it’s as well to know that seeking out an older PYREX dish could be a good move.

If you’d like to know more about glass, we’ve got you covered.

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The High-Tech Valor Glass Vials Used To Deliver The Coronavirus Vaccine

As the world waits for COVID-19 vaccines, some pharmaceutical companies stand armed and ready with an exciting improvement: better vials to hold the doses. Vials haven’t changed much in the last 100 years, but in 2011, Corning decided to do something about that. They started developing an alternative glass that is able to resist damage and prevent cracks. It’s called Valor glass, and it’s amazingly strong stuff. Think Gorilla glass for the medical industry.

Traditionally, pharmaceutical vials have been made from borosilicate glass, which is the same laboratory-safe material as Corning’s Pyrex. Borosilicate glass gets its strength from the addition of boron. Although borosilicate glass is pretty tough, it comes with some issues. Any type of glass is only as strong as its flaws, and borosilicate glasses are prone to some particularly strength-limiting flaws. Pharmaceutical glass must stand up to extreme temperatures, from the high heat of the vial-making process to the bitterly cold freeze-drying process and storing temperature required by the fragile viral RNA of some COVID-19 vaccines. Let’s take a look at how Valor glass vials tackle these challenges.

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