All About Glass

Generally, people know what glass looks like but they may not know what glass is. Glass is defined by Merriam-Webster as "a hard, brittle, amorphous, usually transparent or translucent material consisting typically of silica.". The "material" actually is a liquid of very great viscosity or "resistance to flow in a fluid."

When looking for the right type of glass for any particular purpose, you need to consider:

  • The amount of light transmitted by the glass
  • Solar heat gain allowed by glass
  • Thermal conductivity of glass
  • Where it will be installed
  • Amount of weight or force it needs to sustain

You’ve come to the right place to learn all about glass and glass making. Below is more information about the professionals who work with glass, what glass is made of and what determines the energy efficiency of different glass types. But first, there are so many types of different glass, all with unique properties specific for their use. Click the links below to find out more about each type.

What is a Glazier?

No matter the type of glass, the material is installed or, when damaged, repaired by a glazier. People have known about glass for thousands of years, but few dare to handle it every day. Those who do are glaziers (not glaciers); members of a select, little-known professional trade specializing in glass installation and restoration. As science and research continue to develop new glass products, the glazing profession becomes more complex. People with mechanical ability, detailed thinking and hands-on work skill, who love a new challenge every day, are in high demand nationwide to join the glazing profession. Glass Doctor franchise owners recruit the best glaziers to be glass specialists, especially those who are certified by the National Glass Association (NGA). Glass Doctor specialists are qualified to cut and handle all sizes and types of glass. Because the glass industry is changing quickly, Glass Doctor specialists continue to develop their skills through web-based distance learning tools such as Some Glass Doctor specialists are cross-trained to work on home, auto and commercial glass, while others specialize in one type of glass; similar to general practitioners and specialists in the medical field. While practicing glass repair and replacement is not as complex as practicing medicine, the same care must be taken because the glass is important to the person – the customer – who needs help.

What is Glass Made Of?

Basically, glass is sand; a high-quality silica sand, to which other materials are added. The resulting mixture is called a batch. Other materials in the batch are salt cake, limestone, dolomite, feldspar, soda ash and powdered cullet. Cullet is broken glass. It remains from a previous batch or from the edges that remain after a batch of glass has been formed and cut to size. Adding cullet helps the batch melt easily. Glass making is done by melting and cooling the batch. As the batch cools, it becomes solid without forming crystals. Crystals are three-dimensional building blocks that make a substance internally rigid. The lack of crystals makes glass technically a liquid, not a solid. It also makes glass transparent.

Energy Efficient Glass

One of the biggest differences in glass types is its energy efficiency. Low-E, reflective and insulated glass contribute to energy efficiency by increasing the effectiveness of the insulating system. Energy efficiency is measured in two ways, the U-value and the R-value. The U-value is a measure of the heat gain or loss through glass due to the difference between the indoor and outdoor temperatures. The lower the U-value, the less heat is transmitted through the glass. The R-value measures the overall resistance to heat transfer. The R-value is the reciprocal of the U-value. The higher the R-Value, the less heat is transmitted through the glass. For example, a material with an R-value of 19 is a much better insulator than one with an R-value of 6.

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Have questions about a glass project for your home or business? Contact your local Glass Doctor at 888-516-8133 for upfront pricing, expert workmanship and 24/7 emergency service. We fix your panes!®