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glass moving over time

updated sun 19 dec 04

 

Richard Mahaffey on wed 15 dec 04


Hello all,

I am surprised that no one mentioned that when you measure 200 year old
glass and decide that since the bottom is thicker the glass moves, how
do you know
that the glass was not thicker on the bottom when installed? Bad
science to take a measurement on the end of a time span and make
suppositions on what happened
without a base line measurement.

While in Turkey in October I saw lots of Roman and older glass. It did
not appear to have slumped over time (2K years or so) so how could
window glass that was 200 - 250 years move that much?

We have to make sure that we have the information that we need to make
proper judgments,

Of course Your Glass May Vary,

Rick Mahaffey

Darin Lang on thu 16 dec 04


A simple way to end this argument, would be to find the window built by
a nincompoop, who put the panes in thick side up. ;)

Darin Lang

Richard Mahaffey wrote:

> Hello all,
>
> I am surprised that no one mentioned that when you measure 200 year old
> glass and decide that since the bottom is thicker the glass moves, how
> do you know
> that the glass was not thicker on the bottom when installed? Bad
> science to take a measurement on the end of a time span and make
> suppositions on what happened
> without a base line measurement.
>
> While in Turkey in October I saw lots of Roman and older glass. It did
> not appear to have slumped over time (2K years or so) so how could
> window glass that was 200 - 250 years move that much?
>
> We have to make sure that we have the information that we need to make
> proper judgments,
>
> Of course Your Glass May Vary,
>
> Rick Mahaffey
>
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Robert Seele on thu 16 dec 04


On Thursday, December 16, 2004, at 11:22 AM, Darin Lang wrote:

> A simple way to end this argument, would be to find the window built by
> a nincompoop, who put the panes in thick side up. ;)

That applies to me, butt I don't think I'll be around a hundred years
from now.


Bob Seele

The older we get, the fewer things seem worth waiting in line
for...Will Rogers

Janet Kaiser on sat 18 dec 04


But that is exactly the point! How come old window glass (what we
are referring to here) which shows a difference in thickness,
apparently *always* appears thicker at the bottom? Surely there
would always bound to be those diy who did not know they were
supposed to put it in thick part down, apprentices left to their
own devices by the Master Glazier, the drunken Glazier, someone
momentarily distracted, the contrary Glazier with his own theory
(like if the window is in place long enough, it will slump down
and even out), the Nincompoop mooted below and so on... The very
fact that no matter who did the original installation, there is
yet a uniformity of thin top, thick bottom.... Well that must
suggest that there is another more fundamental reason, even if
there was a tradition or "good practice" about how to install
glass "correctly".

Another point... Not all glass would be manufactured with the
same difference in thickness. So how come an extremely old window
with many little panes of glass, shows a uniform graduation of
thickness in each piece??

For these two reasons alone it convinces me (who BTW would also
be among those who did not to get it right). And if the glass
caused distortion I would chose to put the thicker down one
side... That way I would get an undistorted top to bottom /
full-length view out of at least part of the window! Surely
others would have thought the same? It would also depend on
prevailing weather direction... The thick glass going to the that
side and thinner to the rear of the building... All those sort of
consideration are ignored be this hypothetical window-glass
installation rule!

And anyway, "glass" is not just a uniform commodity. Window glass
would not be lead crystal glass simply because of cost. It is
still extremely expensive to produce!

Another 2p worth from Wales :o)

As to the person who asked why discuss this phenomena at such
length... Well, it would be pretty worthless having a "discussion
group" that did not do just that!! LOL! Oh, you mean glass has no
place on a Ceramics Discussion List?? Well don't tell the vicar,
but there is an incestuous relationship pots and potters have
with glass.

Sincerely

Janet Kaiser -- Here is an excellent aphorism from the Yoruba
people (Benin, Nigeria & Tongo): A gift is a gift, and a purchase
is a purchase: so no one will thank you for saying "I sold it you
very cheap"

*** IN REPLY TO THE FOLLOWING MAIL:

>> A simple way to end this argument, would be to find the window
built by
>> a nincompoop, who put the panes in thick side up. ;)
>
>That applies to me, butt I don't think I'll be around a hundred
years
>from now.

*** THE MAIL FROM Robert Seele ENDS HERE ***
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