Before man learned the secret of glassmaking, nature was the world’s only glassmaker. Lightning striking sand melted it into long, thin tubes of glass, and volcanoes erupting melted rocks and sand into glass.
Man’s earliest glass was probably a glaze on ceramic pottery made somewhere around 3000 B.C.
Today, three inexpensive ingredients, sand, soda ash, and lime, are melted together to make glass. This is done in large furnaces at high temperatures until the mixture become a syrupy mass. When this syrup cools, it is glass.
When glass is in a melted state, it can be shaped by many methods, but the most common are blowing, pressing, and drawing.
Blowing is the oldest method of working with glass, dating back thousands of years. A ball of molten, or melted, glass is put on the end of a hollow iron pipe, and a worker blows gentle into the pipe (much like the way you blow soap bubbles) until the glass takes the shape and thinness the blower wants. During this process, the glass is constantly reheated to keep it soft and workable.
When the glass is shaped to the blower’s satisfaction into a bottle or a vase, it is broken from the pipe. Although glass blowing by hand is still done today, it can also be done by machine.
In the pressing method, a hot glob of glass is dropped into a mold, then pressed with a tool, so the glass fills the inside of the mold. Ashrays, baking dishes, and glass containers are made this way.
The drawing method shapes glass flat, as for windows and mirrors, or into tubes, as for fluorescent lights, TV tubes, and laboratory equipment. To make flat glass, first the melted glass is drawn into a tank of melted tin. The tin’s perfectly smooth surface forms a smooth layer of glass as the glass floats on top of the tin. To make glass tubing, a stream of molten glass is drawn around the inside of a cylinder. As the cylinder rotates, air is blown through it, forming a continuous tube out of the glass.
No matter which method is used, the glass must still go through a process called annealing. In annealing, the glass is reheated and gradually cooled to restore its strength and prevent its shattering. Tempering is also used to strengthen glass. In tempering, the glass is reheated, then chilled by sudden blasts of cold air.
This process should not be confused with another method called lamp working, in which finished glass tubes are heated over a blowtorch, and as the glass worker bends, twists, and stretches the glass, he can create miniature animals, ships, and baskets.
Banks, tanks, aircraft, and some government cars have glass so thick and with so many layers that it can stop a bullet even at close range!
28 Comments
My sci-fi peoject is on glass
What about quartz?
I love this page I got alot of information!!
Rachel
i love glass and Rachel
This was good information, but I was also looking for specifics. Good insight on the history and the three common methods of glass though!!
thx you helped big-time
I wondering why when you named the 3 most common methods and put a paragraph for each one you didnt put one for pressing?
Me I am doing this report and I was wondering if you put alittle more infomation ABOUT NOT how to make it.Also if you can tell me who invented glass,when was it invented,where was it invented,why was glass invented and HOW was glass invented?
hi i am doing the a simapa thng to you so maybe we can help each other out
Thanks alot this really helped me!
Thanks.Big Help xx
el gato
good information
good information
Nice simple language for my year 9 class to find out how glass is made – very good.
Thanks this has helped my year nine students
i got alot of info.
this is all i needed for my science fair project.
can i get how fibreglass is made?
Everbody looks like ants from here!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
OMG I HEARD THE FUNNIEST JOKE….
y is 2×2=4?because 5 is already used!!!!!!!!!!! o wait did i mention that he was A COW?
Me I am doing this report and I was wondering if you put alittle more infomation ABOUT NOT how to make it.Also if you can tell me who invented glass,when was it invented,where was it invented,why was glass invented and HOW was glass invented?………..sri_1Nonly1
thanks very much ur a life saver
On my homework,I have to give the website and author of the article I got my information from.So, if there were an author this would have helped me a lot.
it doesnt say how glas is mad on a large scale !!!!!!!!!!!!!
hay it is very helpful but how is it made on large scale
Thanks for the info, now I can finish my project!
hi can enyone plz tell me wat it is made of cuz i am doing this thing for school so i wounld be thanked if ues could tell me
Hi! thanks for the info dude it really helped!
i love rahul