[OahuAmateurChef]

Has anyone had pyrex explode on them? Any injury? I just found a list of what seems to be hundreds of stories of exploding pyrex here.

This is alarming to me, as I own a few pyrex products, so I figured I'd ask about it here. Any stories to share?

[allie]

The only time I've seen it explode is when my ex-husband decided to reheat something on the stovetop! That was not a pretty sight! He didn't get hurt but glass went everywhere.

[Mezzaluna]

I've had thermal shock cost me a 2-cup measure once. It may have been in part due to the fact that I bought it at an outlet mall; it may have been a factory second (imperfect).

[oldschool1982]

I actually had one that was soaking in the sink after baking Lasagne in it. I think it was caused by the Dishwasher draining and it formed some suction since the pyrex was sitting over the drain. Other than that I've never had a heat related issue.

I have heard if you scratch the surface, like over zealous use of a Scothbrite pad, it can compromise the dish and cause it too break but I've never seen it.

[OregonYeti]

I have the same 9 X 13 blue pyrex baking dish. I haven't had a problem, but I'll be more careful now.

As far as the scratching, one of my industrial jobs was scoring and breaking glass. It doesn't take a whole lot of a scratch before the glass is just "ready" to split there.

[Anneke]

I once turned on the wrong element on my stove. Yes, my pyrex dish was sitting on it. Lucky I wasn't in the room; it was as if a bomb went off. Would have guaranteed me a trip to the hospital. The glass flew in 3 rooms; was cleaning it out of my open shelves for months. I no longer 'temporarily' store anything on my stove top. It was a good lesson.

[OahuAmateurChef]

Originally Posted by OregonYeti

It doesn't take a whole lot of a scratch before the glass is just "ready" to split there.

Do you think this is what causes Pyrex failures?

[OregonYeti]

Originally Posted by OahuAmateurChef

Do you think this is what causes Pyrex failures?

I did some research.

What makes traditional Pyrex able to withstand a certain amount of heat without cracking is its low rate of thermal expansion. Borosilicate glass (the original) has a lower rate of thermal expansion than the new glass, and this is the main reason it doesn't crack or shatter as easily with heat.

If one part is hotter than another, for example, it will expand more and there will be stress built up. One part is "trying" to get bigger but it's restrained because it's connected to the other part. If there's enough stress, it will break. In glass that expands and contracts more with temperature, there is more stress.

A scratch might weaken it, but it isn't the main thing.

As far as how it breaks when it does (a simple crack vs shattering), I don't know but of course it has to have something to do with the crystal structure.

[dscheidt]

Originally Posted by OregonYeti

As far as how it breaks when it does (a simple crack vs shattering), I don't know but of course it has to have something to do with the crystal structure.

One of the advantages of borosilicate glass is that when it does break, it tends to break in large pieces, and not come apart into many small pieces. That's not to say that you can't get borosilicate glass bits to come apart into a bunch of deadly shards; you can, it's just harder.

Old Pyrex branded stuff is made of borosilicate glass; current production (and for the last 10 years or so) isn't. That's in the US; the trademark is licensed by someone else in the rest of the world, I don't know what's sold there.

[OregonYeti]

Well then, the conclusion seems to be that the new Pyrex is just inferior material as compared to the old. That's disappointing, but at least we know how to lessen the risk of failure--by avoiding cool spots and hot spots within it. Heat or cool it uniformly, and no big deal, but have it much hotter in one part than another, and it might pow. I'd rather not have to think about that. I'll avoid the new Pyrex. Thanks for the heads up, Oahu and dscheidt

[Dirk Skene]

You have to really mess up to cause pyrex to pop