As the technology of production of large glass objects is being developed, large demand arises to combine two or more pieces of glass. The practice of recent years proves that this can be done using glass materials with precise dilatation. Our glass meets these requirements; however, it needs to be said that:

• we do not guarantee use of multiple colours in one object of kiln casting; even though we observe the production technology of our glass with utmost care, use of multiple colours in one object is risky
• the large and thicker the glass object, the more tension remains in the glass (glass is a toughened melt and the tension can never be completely removed from it during cooling)
• during passage of thermal rays through the glass object the light is filtered to various components which have different thermal character and therefore they can warm up the object irregularly – obviously due to low thermal conductivity of the glass this is happening especially on the surface of the glass object, however this causes the risk of excessive tension inside the object
• in order to reduce the risk it is necessary to perform dilatation test on a small sample prior to production of large glass object, i.e. to cast the glass materials, properly cool them and check joints of individual colours under polarization scanner – this will minimize the risk of using incompatible glass materials

Conclusion: many artists are successfully using multicoloured production of glass objects from our materials and they are able to explain to the customers where the object can be placed so as to minimize the risk of tension due to external effects.

In order to reduce these risks we are developing new glass materials. In 2012 we have managed a small miracle and we have developed :  a specific low-dilatable glass EX, which can be used outdoors.