Sciencemadness Discussion Board

pyrex vs PYREX

Syn the Sizer - 18-4-2020 at 14:55

Hello everyone,

I have heard a few time that there is a difference between pyrex in lowercase and PYREX in upper case. I did a search in the forum and didn't see anything related to this.

The (extended) story is pyrex in all lowercase is sode-lime glass licenced by Corelle Brands and sold in North/South America and Asia, PYREX is high quality borosilicate glass licenced by International Cookware sold in Europe, Africa and Middle East.

I googled and found it to be true and now will be watching when making online purchases. I just thought of posting this because I just blew up a pyrex bowl lol.

Syn

clearly_not_atara - 18-4-2020 at 15:16

Also, I'm pretty sure that the true borosilicate pyrex tends to be thinner than the cheaper soda-lime stuff.

Not that thick soda-lime glass doesn't have its place. Those heavy, cheap Pyrex/Anchor bowls are great for using a hand mixer. You wouldn't want to do that in a borosilicate bowl -- it's too light and it would crack. Borosilicate has to be handled with care, which is probably why it has been so hard to reintroduce borosilicate cookware to the American market after it was removed. Everyone is used to crack-resistant glass now.

There is a small company called Borosil that sells true heat-resistant cookware, but it's kind of expensive. They're available on Amazon.

[Edited on 18-4-2020 by clearly_not_atara]

Syn the Sizer - 18-4-2020 at 15:51

I believe you are right, borosilicate being more heat resistant can be thinner which also promotes better heat transfer

To be honest I would prefer the higher heat resistance of borosilicate to the crack resistance of soda-lime glass.

I ef'ed up and let the water bath run dry and the bowl didn't like it too much, though even borosilicate will crack when ran dry just not so easy, and I don't believe it explodes like soda-lime.

PirateDocBrown - 19-4-2020 at 11:23

The real problem when they first marketed boro cookware in the US was that they even sold saucepans made of the stuff, that went right onto the flames of a stovetop. People would then often put them straight into a sink full of water for clean up, and not even boro can take that kind of thermal shock, and you would get explosions of glass shards. Too much liability for Corning, so they stopped making it.

SWIM - 19-4-2020 at 11:59

I've got a lot of old PTREX cookware.
Little of it is thin like an RBF.

Most of it is like a polymer reaction kettle, which must be like 3 times thicker.

I think that's because cookware is going to get slammed around more than labware, so they were compromising between thermal shock and impact resistance. I mean face it: you're gonna be a lot more careful with sulfuric acid than you are with ham. (Or lamb, if that's your strong-flavored meat of choice.)

I've got a PYREX pot which I used for years without breaking, but I never put it straight in the sink from the stove, and I avoided using it for any really high temperature uses.

I do now have some mixing bowls which seem to be thin boro glass, but they're unmarked.
They have edges about as thick as a standard (non HD) Ace flask.
(I got a broken 3 liter one in the mail recently, so I had an easy time comparing)

You know they actually made a Vycor frying pan back in the 30s. Not sure if there was mass production or if it was just a prototype, but it was octagonal like the Vycor logo. I figure that baby would take just about anything kitchen equipment could have dished out.

Let's deep fry something in molten lead and then put the pan on a block of ice to cool it?
Sure! Why not?

WARNING: Food deep fried in molten lead may cause constipation.

Syn the Sizer - 19-4-2020 at 12:17

That makes sense as to why they would stop producing it for kitchen use, kinda like a hot water nail bomb. I definitely treat sulfuric acid with respect where as I treat ham like a piece of meat lol.

I want to get PYREX for my lab work, I would rather borosilicate over soda-lime. Plus for kitchen use it's more reliable.

Syn the Sizer - 19-4-2020 at 12:31

Quote: Originally posted by SWIM  


You know they actually made a Vycor frying pan back in the 30s. Not sure if there was mass production or if it was just a prototype, but it was octagonal like the Vycor logo. I figure that baby would take just about anything kitchen equipment could have dished out.


Need to get a Vycor round bottom flasks so a person can feel a little safer distilling H2SO4?
Quote: Originally posted by SWIM  

WARNING: Food deep fried in molten lead may cause constipation.


That's probably been my problem all these years!