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Category Archive: Glass Tempering

FAQ — Thermal Glass Tempering

Tempered glass is one of the most popular choices for applications in which traditional, or annealed, glass may pose a safety hazard.

For nearly 100 years, Swift Glass has been providing quality custom glass fabrication services for a wide range of industries. To provide insight on the thermal glass tempering process and its various benefits, our experts have provided answers to some of the most common questions we field here.

Check out the FAQs below.

Is thermal glass tempering the same as chemical strengthening?


Tempered glass undergoes an intense heating process immediately followed by rapid cooling.

The extreme temperature shift causes the glass surface and edges to compress, creating an extremely tough outer surface with a tensioned glass core.

Material properties are enhanced, making the glass as much as five times stronger.

In contrast, chemical strengthening — also known as ion exchange — treats glass by submerging it in a molten potassium salt bath, causing sodium ions in the glass to be replaced by potassium ions from the bath.

The potassium ions, which are larger than the sodium ions, squeeze themselves into the gaps left by the smaller sodium ions when migrating to the potassium solution. The surface of the glass is then in a state of compression while the core is compensating tension.

Both of these glass-strengthening methods alter the outer surface of the glass, causing it to have a higher compression than the interior glass, which is in a state of tension. Depending on the specific application, each process offers unique advantages for a material’s final composition.

Can you thermally temper quartz?


Because of the high optical and thermal properties of quartz compared with other types of glass in their natural state, quartz cannot be tempered.

What glass materials can you temper?

  • Borosilicate
  • Float Glass/Soda-Lime
  • Starphire
  • Various Patterned Glass`
  • Solar Grey & Solar Bronze

Will tempered glass always shatter into tiny pieces?

Not always. It depends on the material.

The chemical makeup of different types of glass determines whether the glass will break into small, smooth pieces or sharp, jagged edges. For example, soda lime glass always breaks into small pieces unless it has been subject to temperatures above 450 °F.

When glass is subject to temperatures above this point, the glass begins to weaken and returns to the annealed state. Once this happens, the glass will break into shards.

Materials such as borosilicate, on the other hand, will not necessarily break into tiny pieces when tempered.

What is the largest size piece of glass you can temper?

The thickness of a piece of glass will determine the size you can temper. At Swift Glass, we can temper glass at 34 inches x 72 inches for pieces up to 1 inch thick.

For glass pieces with a thickness up to 2 3/8 inches, we can temper up to a size of 14 inches x 14 inches.

What is the thinnest glass you can fully temper?

  • Soda Lime — 0.125 inch thick
  • Borosilicate — 0.3125 inch thick

Where is tempered glass used?

Tempered glass can be found in a range of applications, including:

  • Sight Glass
  • Boating Windows
  • Lighting Products
  • Industrial Applications
  • Appliances
  • Vehicles
  • Explosion & Bulletproof Solutions

The tempering process changes the composition of the glass, giving it strength, durability, and scratch-resistance.

Tempering allows thin glass to withstand harsh environmental conditions without losing its functionality.

And since tempered glass can easily withstand temperature fluctuations, it’s well-suited to a wide range of industries, including:

  • Aerospace & Aviation
  • Architecture
  • Automotive
  • Buildings
  • Energy
  • Lighting

Learn More

Curious to learn more about tempered glass and its various uses? Download our comprehensive eBook, “Creating Glass That Withstands Extreme Environments.

Manufacturing Strengthened Glass for Extreme Environments

High-intensity industrial processes call for durable equipment that will prove resistant in the face of even the toughest of applications.

Sheets of Factory manufacturing tempered clear float glass panels cut to sizeIf you’re carrying out procedures against harsh or extreme conditions, it’s essential that your application is equipped with the proper glass component. Tempered safety glass in windshields, for example, provides extra security in the event of breakage.

High performance glass is required to withstand a vast range of pressures, elements, and external factors, each of which vary by industry. When operating in high intensity environments susceptible to extraneous factors, it’s important to be aware of common concerns that can arise.

Below are a few common risks associated with extreme industrial climates, along with the glass strengthening solutions that help reduce those risks:

High-Pressure Exposure

One of the most frequently noted stress points for high performance glass, this can manifest itself in marine, architectural, and even aeronautical environments.

Strengthened glass, however, can help prevent or reduce the adverse effects of high pressure. In addition, strengthened glass helps shield your work environment from harm caused by explosions, bullets, and projectile aftermath, each of which may pose a threat to safety and productivity. Safety glass offerings, like tempering, can help to ensure a less devastating effect upon impact than with regular glass.

Extreme Temperatures

Exposure to extreme temperatures can result in potentially adverse effects upon operations. Fortunately, heat-treated glasses can offer dramatically increased protection against hazards like thermal shock. Heat treatment offers glass—a material often susceptible to high temperatures—increased protection against high-temperature breakage.

Harsh Environments

Exposure to intense, abrasive elements or harsh, wet and extreme environments holds the potential to work against high performance glass. For certain extreme or outdoor environments, heat-tempered glass may not be necessary, but it can provide exceptional resistance against thermal stresses and extreme wind pressure. Fully tempered glass, however, can offer unparalleled safety when it comes to ensuring safety break pattern. If operations are under harsh weather conditions, tempered glass ensures your work environment remains both active and safe.

Learn More in Our eBook

At Swift Glass, we’re dedicated to providing consumers with the high quality materials they need for safe, efficient, and effective day-to-day procedures. For additional information regarding glass strengthening solutions, access our new eBook titled Creating Glass That Withstands Extreme Environments.


The Benefits of Glass Tempering and Strengthening

We interact with glass every day — we look through it, drink from it, and it helps us see clearly.

Thermal temperingBut not all glass is the same, and our ability to modify glass and improve its qualities is what allows us to use glass in applications where it would have been a safety hazard.

This modification process is referred to as glass tempering. Tempering is achieved through a thermal process. Chemical strengthening is achieved through an exchange path.

The heat tempering process involves subjecting glass to very high temperatures and then cooling it quickly. During chemical strengthening, chemicals applied to the glass change the surface to create compression.

In both instances, the outer surface of the glass is altered so that it has a higher compression than the interior glass which is in a state of tension.

This specialized glass has allowed industries to use strengthened glass in a wide variety of applications, as it delivers a variety of benefits:

  • Safety
    Tempered glass does not break apart and shatter as ordinary glass does. If the glass is broken, it will break into circular and small pieces and not sharp jagged shards that could cause harm. It is also easier and safer to clean up broken tempered glass without causing additional injury. Because of this it is widely used in high-pressure and explosion proof windows, lighting products, and doors for industrial and residential applications.
  • Durability
    The tempering process changes the composition of the glass giving it strength, durability, and scratch resistance. Tempering allows thin glass products to withstand harsh environmental conditions without losing their functionality. In medical, semiconductor, and energy applications, tempering enables glass to be successfully incorporated without fear of component failure.
  • Temperature resistance
    Its ability to withstand temperature fluctuations makes tempered glass suitable for aerospace and aviation applications, laboratory equipment, and household items. The ability to withstand high temperature and variations in temperatures makes this glass ideal for use in buildings to meet fire code regulations, fire engines, appliances, drinking glasses, cookware, and laboratory glassware.

Swift Glass is a leader in manufacturing tempered and strengthened glass for a wide range of industries and applications. Our extensive material selection includes float glass, Pyrex®, and Borofloat®.

Visit our website for more information about Swift Glass’s thermal glass tempering and chemical glass strengthening processes.


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