Glazing Technologies

Decorative Glass: Kiln Formed Patterns

As the name suggested these effects and patterns are created using a kiln oven. A huge variety of effects can be created using this glass decorative method. For smaller patterns and for patterns on thinner glass the pattern or design is designed by hand on a fire rated board, indenting, texturing and scouring the malleable board with the view to achieving a pattern of choice.

For larger patterns and thicker panes of glass, the pattern is designed on a mould created using plaster, sand and chemicals bespoke-ly to suit each unit and design.

All pattern designs have to be made on a level block design table to make sure all pattern templates are completely flat, ensuring even glass thicknesses over the patterned effect.

For each case, once the design has been finished and approved it is fitted into the base of the kiln oven. These ovens can hold huge sizes of glass of over 18m2 in order to meet the design criteria for a wide variety of projects. Once the pattern base is in place the glass is then lifted and laid flat onto the pattern board inside the kiln.

Specialist Kilns

The kiln is heated to temperatures upward of 800°C until the glass takes on a molten quality. In this state, the glass will mould to the pattern shape etched into the board below it and the design is then acquired.

For coated glazing, be that Low-e or solar control, a slightly different kiln is used. As the coatings applied to the glass reflect heat the glass unit has to be heated from two directions, both above and below, to ensure the glass is formed properly. Specialist kilns using electrical heating at the bottom and radiant heating from above are utilised to kiln form coated glass.

This process can take anywhere from 10-14 hours depending on the glass thickness and then is cooled in what is called the Annealing Process. The cooling must be done at a very steady pace, ensuring the glass is cooled slowly and evenly to ensure no glass breakages occur due to thermal shock.

Once the Kiln formed design is ready the glass can then be tempered, toughened or laminated.