Ravensby Glass have recently invested in their heat soaking facilities due to increasing market demand for this process. They have doubled their heat soaking capacity by purchasing a second Torgauer oven.
Due to the regulated duration of the heat soaking process, there is a limit on capacity which can only be expanded with the introduction of an additional oven. The tempering process of glass increases the strength of glass around 5x. However, the tempering process can cause problems if the float glass used has microscopic inclusions within it. Nickel sulphide particles formed in the production of the float glass will cool down at a different rate to the rest of the glass. This can result in the toughened glass shattering, seemingly spontaneously. The heat soaking process serves to identify any problematic sheets of toughened glass. The tempered glass is heated to a temperature around 290C for a minimum of 2 hours and then cooled slowly which forces the nickel sulphide particles to transform to their low-temp state during the process, causing the toughened glass to shatter in a controlled environment. Heat Soaking will identify more than 95% of problem panes.