The answer to this question is BOTH!
Natural glass is known as obsidian. Our curious and inventive ancestors tried to imitate what they saw in nature. They noticed that the sand melted when placed near the fire and they liked the results. Centuries of development later resulted in the glass you use today.
So how is glass made today?
Ingredients
To make glass you will need the following ingredients:
Silica sand)
sodium carbonate
Calcium oxide (from limestone)
Much hot!
Optional ingredients:
To get different effects, such as color, you can use one or more of the following options:
Cullet (recycled glass – see below in the Recycling Section)
Magnesium or aluminum oxide (can be used instead of calcium oxide)
Lead (if you want to make crystal glasses)
Boron (to change thermal and electrical properties)
Lanthanum oxide (if you need improved light reflective properties)
Iron (to absorb infrared energy)
Color (change the color by adding various metals or oxides)
Coatings (you may want to coat your glass to give it a special finish).
Much hotter!
process
1. Heat your ingredients to 1,500 – 1,600 degrees C and cook for up to 50 hours.
2. for float glass (sheet), allow the molten glass to flow over a layer of molten tin. Add any coating you wish to use and allow to cool slowly in an oven.
3. for drinking vessels and vesselsFirst, make a “parison” or preform (thick miniature bottle shape) by pressing or blowing a blob of molten glass (called a gout) into a shape using a mold. Place the preform in another mold and use compressed air to push the sides out into the shape of the final bottle or glass. Cool, reheat, and allow to cool again (this prevents breaking).
Don’t try this yourself at home!
recycling
Glass is an excellent material to recycle: it can be reused over and over again. Saves mining of raw materials and requires much lower temperatures.
When you send your glass in for recycling, it will be cleaned, color-sorted, and processed to remove any impurities. This will leave “cullet”. This is added to the raw ingredients where it quickly melts and is added to the mix.
So now you have a brief knowledge of how glass is made!
Copyright: You may freely republish this article, as long as the text, author credit, active links, and this copyright notice remain intact.