Does Pyrex Glass Warp?

Interesting, I've never seen such a thing. I would suspect if the raised portion has any void of material (IE a bubble), It could definitely present a danger of explosion due to the expanding gasses trapped within. I'm curious to hear any explanations anyone has on the issue. I've owned my fair share of Pyrex cookware and have never seen that happen, and you say you have "several" dishes that have these symptoms. I would have to guess that it might be a more local problem with some other aspect causing such a phenomenon, rather than the dish itself.

One raised area per dish?

yes, roughly in the center, about 3 X 6 inches, roughly oval

Hi wldnwly,

Of the ones I have had, at least some of them come with the center raised a bit - just like you have described. Maybe it's by design or how they are processed. Are you sure that they were not like that before subjecting them to heat?

Mike

Interesting - they actually weren't mine, but a relative's where I was helping out, so I didn't see them until the raised area was pointed out. However, some of the pans did not have the raised area, so I don't think they are deliberately made that way.

Are you sure they're the genuine article (not rip-off copies)?

He meant, "are you sure they are not made in China?"

If somone made a knockoff of pyrex they would probably use soda lime (window glass). Properties of Pyrex: Softening Point: 1510 °F (821 °C) Soda Lime: Softening Point (ASTM C 338) 1319°F (715°C). So for oven temps it probably wouldn't slump on you.

Do you see pitting also. Is this made in china and is not a real pyrex. To safe few penny people tried to mimic pyrex with borosilicate glass which is typically window glass.

You can find out very quickly by boiling water in that and observing suface after water evaporated areas withlocation of dried sodium oxide at dry stage.

If pyrex is manufactured in the area where people are melting leaded glass then cross contamination will also do.

In any case I will not use this for cooking