In a message dated 98-08-24 19:23:07 EDT, larry@netkonnect.net writes:
<< They also suggested in storing it upright like they do, and not laying
on the face, as it may distort from its original shape. I learned years
ago in physics that glass is a liquid, yes, a liquid. Look at Colonial
house window panes and you can see the flow, even though it is very,
very slow.
>>
Larry, This is a myth. Due to the manufacturing process of glass, years ago it
came out thicker on one edge. It was customary in those times to install the
glass with the thick side down, leading to the myth. They have found glass in
old churches and houses where the glass had been originally installed upside
down and was thicker on the top. It would take thousands of years for window
panes to noticably creep vertically from compression due to gravity.
I agree that windshields however, should be stored on end to eliminate the
high bending stress that will cause creep. This is true many materials.
John Logan
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