How to Cut Tempered Glass Shelves?

Tempered or toughened glass is commonly used in glass shelves and other glass applications around the home as it gives the décor elements augmented strength & durability. This high-strength tempered glass is relatively 4-5 times stronger than the ordinary glass and is best-known as safety glass as it doesn’t shatter into sharp harmful pieces of glass. This glass is simply an ordinary glass made stronger by undergoing a process called tempering and can also be returned to its original state by undoing the tempering process or annealing process. 

The Annealing process has one big advantage as it allows you to cut the toughened glass in customized shapes & sizes. This is done with the help of a kiln, as the whole process requires subsequent heating and cooling of the glass. 

Is it really possible to cut a shelf made of tempered glass?

Many homeowners are still confused about this exceptional characteristic of toughened glass. A lot of us have ample toughened glass lying around the home and the best way to utilize it is by cutting the glass into desired shapes & forms. In this way, tempered glass from tabletops and other applications can be used to cut a beautiful and elegant glass shelf

To understand how this is possible, it is important to know how toughened glass is prepared in the first place. This glass type is strong because of the presence of internal stresses in the glass, these stresses account for augmented strength, durability, and unique safe breaking mechanism of toughened glass. By undoing the process of tempering by subsequent heating and cooling, these strength-providing stresses are eradicated allowing the glass to be customized, fabricated, or cut in any shape, form, or size.    

Procedure to cut tempered glass shelves

The process of cutting tempered or toughened glass is the same as cutting the ordinary or untempered glass. However, before doing so, the safety glass undergoes an annealing process that converts the toughened glass back to its original form. Following are the six key steps for cutting tempered or safety glass shelves:

  • Step 1 – Heating the Tempered Glass

Procedure to cut tempered glass shelves

To cut a piece of tempered or toughened glass, first, it must be heated to a high temperature of 468 degrees Celsius or 875 degrees Fahrenheit. This can be done in kilns commonly used in art studios and art classes. To heat a glass piece in a kiln, a heat-proof vessel of adequate size filled with warm water is required to place the glass. The exact heating temperature varies with the quality and type of safety glass and is normally between 468 degrees Celsius to 566 degrees Celsius. 

  • Step 2 – Cool Down the Heated Glass

The next process is to cool down the heated piece of glass by lowering the temperature of the kiln down to 427 degrees Celsius. Some type of tempered glass requires an even cooler temperature up to 399 degrees Celsius. However, it is essential to cool down the glass gradually as rapid cooling can result in extra loss of stresses making the finalized glass weak & fragile.

  • Step 3 – Take the Glass Out from Kiln

The glass piece must be removed from the kiln once it has sustained the cooling temperature for up to two to three hours. Using tongs remove the glass and place it on a cooling rack for overnight cooling. It is never recommended to cut the toughened glass while it is hot or to cool down the glass piece rapidly as this results in the lesser buildup of internal stresses.

  • Step 4 – Clean the Glass and Mark the Cutting Line

Following this, the glass piece must be cleaned with window cleaner and a well-defined line must be marked on its surface with the help of a ruler. A permanent marker is the best to use for marking lines on the glass surface. 

  • Step 5 – Cut the Annealed Glass with Glass Cutter

Finally, the annealed glass can be cut into any desired form or shape with the help of a simple glass cutter. It is important to remember that now the glass has undergone the annealing process and is just like ordinary glass. This means it is no longer safety glass and safety goggles must be worn when cutting the annealed glass piece.

  • Step 6 – Place a Wooden Dowel and Apply Pressure with Hands

Lastly, place a wooden dowel below the marked line and equally apply pressure on both the sides with hands. This will easily split the glass into two parts of the desired shape & size. Following this, the roughened edges of the glass must be smoothened with the use of the sandpaper.

Cutting tempered glass shelf make it annealed

Cutting a tempered glass is certainly possible and can be done even in the luxury of home or in a nearby art studio. However, it is important to remember the finalized glass piece is no longer tempered or safe as it is now simply an annealed or ordinary glass.