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gutter_ca
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From Pyrexware.com :
"Pyrex glass bakeware is, and has always been, durable, reliable and safe.
The U.S. Consumer Products Safety Commission conducted an investigation in 2008 and concluded that Pyrex glass bakeware does not present a safety
concern.
While both borosilicate and soda lime are appropriate compositions for glass bakeware, heat strengthened soda lime is more resistant to impact
breakage - the far more likely cause of consumer injury according to national emergency room data.
World Kitchen did not change the product composition for Pyrex glass bakeware.
Pyrex glass bakeware has been made – first by Corning Incorporated and now by World Kitchen – using the same soda lime composition and
heat-strengthening process for more than 60 years.
World Kitchen has always manufactured Pyrex glass bakeware in the U.S. and our packaging proudly displays the American flag and the “made in the
USA” label.
World Kitchen, which purchased the Pyrex consumer products business from Corning Incorporated in 1998, is a U.S. company based in Rosemont, Illinois"
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Dr.Bob
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That is partly correct, Corning had made SOME of its bakeware out of soda lime glass for the past 60 years, but now ALL of it made in the US is soda
lime glass. But much of the Pyrex bakeware was borosilicate glass up until around 1988, when Corning started cheapening it, and then they sold it to
World Kitchen, who may or may not have appreciated what the difference is. Either way, household bakeware is not useful for lab work now.
Most Pyrex labware is now made in Germany or England, as they don't manufacture much borosilicate glass in the US now, due to environmental issues and
such. I don't know if Ace, Chemglass or other companies now make their own, buy the raw glass in the US, or import it all now.
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watson.fawkes
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Quote: Originally posted by Dr.Bob  | | Most Pyrex labware is now made in Germany or England, as they don't manufacture much borosilicate glass in the US now, due to environmental issues and
such. I don't know if Ace, Chemglass or other companies now make their own, buy the raw glass in the US, or import it all now.
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Insofar as I am aware, there are only four major primary producers of raw borosilicate glass, with their
associated brand names: Schott (Duran), Corning (Pyrex), Kimble (Kimax), and Kavalier (Simax). Kimble Chase evidently also owns Bomex, as I found out
on their company location page; it was news to me. I don't know where the factories are now, but the companies are German, US, US, and Czech, respectively.
The compositions of the various glasses aren't identical, but they're close, and they have closely matching coefficients of thermal expansion, so they
can be worked interchangeably. Disclaimer: There are likely other producers outside of North America and Europe that I'm not aware of.
Ace and Chemglass are fabricators; they buy their glass from other producers. I don't know who their suppliers are.
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S.C. Wack
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| Quote: Originally posted by Dr.Bob | | Most Pyrex labware is now made in Germany or England, as they don't manufacture much borosilicate glass in the US now, due to environmental issues and
such. |
Dubious statement is dubious; reference?
The usual over and over
http://www.sciencemadness.org/talk/viewthread.php?tid=3384
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Arthur Dent
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I've had "pyrex" brand glass shatter, but it was entirely my fault.
I was preparing basic Copper Carbonate, my resulting mixture was put in a glass baking pan (8X8) directly on a hotplate element, and upon dessication
of the mixture, I did kind of a nitwit thing without thinking...
I took the pan away and deposited it on the concrete floor. Then 30 seconds later, I hear a little noise... crik TCHING! The damn thing just split
cleanly in half. That was my favorite drying pan!  The temperature difference was
simply too much and the thermal shock did its dirty deed.
I replaced the pan since, opting for a used pan that I bought at a thrift store for a buck, and it looked very old but not scratched. I feel more
confortable with a pan that saw a lot of usage than a brand new pan that might not be up to specs.
So far the old pan has performed its duties without a problem, but I don't remove it from the heat without proper thermal isolation. Usually, I just
deposit it on an old newspaper, which prevents the excessive surface temperature differences.
But I have to admit that I do not "bake" the glassware at extreme temperatures, I mostly use this to boil away water from solutions outdoors on my
porch, and never at the max temperature of the hotplate.
Robert
--- Art is making something out of nothing and selling it. - Frank Zappa ---
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Dr.Bob
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The main reason for changing to soda lime glass is cost of materials, higher working temps (thus higher energy costs), and shorter life of equipment,
but for some examples of the environmental issues of borosilicate glass production see:
http://thestatsblog.wordpress.com/2008/02/29/pyrex-soda-lime...
http://www1.ifc.org/wps/wcm/connect/384e20804885574ebc0cfe6a...
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malcolmf
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| Quote: Originally posted by Dr.Bob | That is partly correct, Corning had made SOME of its bakeware out of soda lime glass for the past 60 years, but now ALL of it made in the US is soda
lime glass. But much of the Pyrex bakeware was borosilicate glass up until around 1988, when Corning started cheapening it, and then they sold it to
World Kitchen, who may or may not have appreciated what the difference is. Either way, household bakeware is not useful for lab work now.
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Ah, then the stuff I've got might be OK. I discovered it abandoned in my deceased mother's outhouse, and, from vague memories of it, it must be
about 20-30 years old. Not a scratch or chip on any of it. Just a 10+ year thick layer of dust and grease. Saucepans, and even a frying pan in a heavy
brown glass. If I recall correctly they were intended for use directly on a cooker ring: (a frying pan??!) and decades old vague memories associate
them with a brand name of "Vision".
Ah, I've just googled it, and it's Corning borosilicate from before the change to soda glass. A treasure trove!
This will be very handy.
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grndpndr
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| Quote: Originally posted by tryptamine | Well what would you expect when you are using the dish outside of the manufacturers stated uses....
You did something foolish and have no right to be pissed off, but you did learn something...
In my line of work in a research/industrial setting I've seen engineers buy perhaps 30 pyrex baking dishes to store 100 degree calcine as it exited a
furnace. After the first one blew up in the hands of an operator the rest of the dishes ended up in the trash bin... |
It would seem the 'engineers' "in your line of work".. "did something foolish"...hopefully they learned something as well!My wish was that the
engineer that selected the dishes was the the one who held the dish that exploded ratether than a min wage operator.
The definition of smug comes to mind.I dont wish anyone ill but when that accident happens!LOL
[Edited on 12-5-2012 by grndpndr]
[Edited on 12-5-2012 by grndpndr]
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