Is Window Pane Glass really Glass?
Is Window Pane Glass really Glass?
(OP)
I wanted to reproduce the wavy glass in my parents old house with a similar pane(and yes it is because I broke it). Can this be done by heating the glass in an oven?
I have heard that newer glass panes are different. Is this true?
tod
I have heard that newer glass panes are different. Is this true?
tod





RE: Is Window Pane Glass really Glass?
To exactly replicate the wavyness of the original is likely going to be expensive and difficult. (I would go looking for abandoned structures of similar age, get a piece larger and have it cut to fit)
Im not sure whether or not the chemistry of modern window glass (the simple kind not the really ultra new super efficient etc. glasses) is that much different from old glass.
nick
RE: Is Window Pane Glass really Glass?
TTFN
RE: Is Window Pane Glass really Glass?
RE: Is Window Pane Glass really Glass?
Old window glass appears wavy due to both the original method of manufacture, and because it slowly creeps under its own weight. Use a micrometer and compare the thickness top and bottom.
It won’t cost much to do some oven experiments. Heat with panes ~vertical, let cool (unless you have some very high temperature gloves), rotate 90o and repeat. The older glass may also have a faint bluish color characteristic of less pure flint glass [more experimentation].
edrush,
"liquid metal" is liquid tin at about 1000oF. Mercury is unsuitable due to its high vapor pressure/low boiling point, 356.7oC. The properties which make tin suitable for the ‘float glass’ or ‘Pilkington process’ are a moderately low melting point, extremely low vapor pressure (doesn’t boil until 2602oC), high density (otherwise, no float glass!), non-wettability and inertness to molten glass. The non-wettability/inertness is because tin is more noble than Si, Ca and Na. Window glass is composed of about 72% SiO2, 14.3% Na2O, 8.2% CaO, 3.5% MgO, 1.3% Al2O3 and traces of other oxides. Liquid Al would be unsuitable as a float base since it can reduce SiO2 and Na2O, plus it is only slightly more dense than molten glass, so more difficult to maintain a flat base.
The float glass process used for window glass manufacture is described and shown at http://www.pilkington.com/corporate/english/education/f...
Hope this helps,
Ken
RE: Is Window Pane Glass really Glass?
Check out http://math.ucr.edu/home/baez/physics/General/Glass/gla...
This is an interesting article on whether glass is a liquid or a solid. It answers part of your question.
JHG
RE: Is Window Pane Glass really Glass?
A more enjoyable and fun way to search for your glass panes is to go to the spring antiques shows held in May at Brimfield Mass. http://www.brimfieldshow.com/ or look up some of the restoration salvage companies that stock pile old windows with wavy glass. There are some antique shops that also specialize in old replacement glass windows and trim. Happy hunting. I bet your parents were really pissed.
RE: Is Window Pane Glass really Glass?
"Old window glass ........ slowly creeps under its own weight. Use a micrometer and compare the thickness top and bottom."
I have never believed this - the rate of creep, even if it were a fact, would be too small to be visually obvious over the relatively brief time span since the mediaeval period, and it was cursory observations of such crudely made glass that first gave rise to the idea. I am also skeptical that anyone has ever demonstrated the effect by using a micrometer on more modern glass. I think it's one of those things that gets repeated in textbooks over and over until someone actually investigates it carefully, and I think it has been somewhat debunked. Of course, I could be wrong, but see the following:
http://www.glasslinks.com/newsinfo/supercooled.htm
http://www.math.ucr.edu/home/baez/physics/General/Glass/glass.html
RE: Is Window Pane Glass really Glass?