About Glass

A Little Bit of Info About Glass Fabrication

When someone mentions glass, most people probably think about windows. This is an understandable reaction when you consider almost every building has some kind of glass window. Glass can be so much more than just windows though. Developments in diamond technology in the last fifty years have made it much easier to transform glass into a thing of beauty. Beveling is one of the most popular ways to increase the beauty of glass.

A bevel is simply when the edge of the glass is ground away at some angle and polished. This angle on the edge of the glass bends the light that is passing through the glass and produces a look that people consider very attractive. People do take for granted the process that must be performed in order to obtain a clear bevel on a piece of glass. When you cut metal, wood, or plastic, you are performing a shaving process. That's why you end up with a pile of long, stringy pieces of material on the floor we call sawdust.

Glass is different. The chemical structure of glass is cristatine, meaning the molecules are stacked in a very consistent pattern. These molecules are bonded very well to each other and cannot be shaved apart. Glass is cut only by forcing the molecules apart. If you were to take a hammer to a piece of quarter-inch plate glass, it would be impossible to put a nice clean bevel on it. But glass is beveled by use of an impact process. The trick is to perform many tiny impacts with the surface of the glass.

A modern beveling machine uses spinning wheels that have synthetic diamonds imbedded in a brass or resin bond. The glass is passed over these wheels by a conveyor that holds the glass very tightly. The glass passes over a series of wheels that have progressively smaller and smaller sized diamonds. Each wheel makes smaller and smaller chips on the surface of the glass until the chips are so small that the glass feels smooth to the touch. The glass then goes over a series of felt wheels that are sprayed with a slurry of cerium oxide. This material is quite rare but has the ability to polish glass better than any other known product. The cerium oxide actually chemically reacts with the freshly ground surface of the glass, forming a product called cerium cilicate. The felt wheel, which is simply tightly bound cotton, then rubs the cerium cilicate off the surface of the glass, exposing the perfectly clear glass surface below.

Beveling is only one edge profile that can be obtained on a piece of glass. Rounded edges, stepped edges, ogee edges, and flat edges can all be obtained using essentially the same process as beveling. To obtain these shapes, you simply use a wheel that is in the shape of the edge you want. Holes are also drilled using the same diamond matrix bonded to a tube-shaped piece of metal.

All of these controlled breaking processes do produce one undesirable result. Friction encountered in the process produces a great amount of heat. When glass is heated unevenly, it expands, therefore breaking the molecular bonds and shattering. To combat this build up of heat, water is constantly sprayed on the wheels at the exact point where the diamonds are contacting the glass surface. All glass edging machines have extensive coolant circulating systems that keep the glass cool enough to obtain the desired edge.

There are only a handful of companies in the world that manufacture glass edging machinery. Most of them are in the Mediterranean area of Europe. The machinery is relatively rare and is very expensive. The machines are built to last and with the proper maintenance provide many years of service and produce millions of inches of edgework.

Hopefully this information will give you a better understanding of the glass edging process. In the coming years, technology will certainly only improve and provide even more exciting options for glass. Windows are certainly a very good use of glass but it is nice to know we can do so many other fantastic things with this marvelous product.

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