Īsumā par stikla krāvuma tehniku kā monumentālās tēlniecības veidu

Author: glass artist Ernest Vitin (Ernests Vītiņš), 15/10/2021

What is layered glass, aka stacked glass technique?

The term 'layered glass' is often used interchangeably with 'stacked glass' - it is the same technique, and one may use any of the two terms to denote the specific process of making a glass sculpture. Nevertheless, for the sake of consistency, the term - layered glass will be used. 

Layered glass sculptures have a unique visual character. Their interaction with light - its reflection and translucence, make the sculptures incredibly expressive. Thanks to these qualities, they are incomparable with any work of art created from any other material or technique. The layered glass technique is a full-fledged medium of artistic expression through which one can create various-sized sculptures - from small, table-size objects to multi-storey building-size sculptures. The greenish tint of the ordinary glass sheet (Clear glass) and the pronounced multilayer texture are typical of such artwork. However, the tone may differ depending on the glass used, and some artists prefer to smooth the surface by polishing it. Compared to other traditional sculptural expressions, such as stone, bronze, wooden sculptures, and hot glass methods - works of art created in the blown glass technique, sculptural objects in the layered glass technique are new and, therefore, are rare in occurrence.

In simple words, we can describe the layered glass technique as follows: it is a cold glass working method when parts of the required shape and size are cut out of factory-produced glass sheets, stacked on top of each other, with or without binding, thus obtaining the desired, glistening sculptural object. The layered glass technique may at first glance, be misleading with its apparent simplicity. But it is solid artillery of mental and physical skills and knowledge that the layered glass technique hides under its unpretentious name. The application and study of these is the only way for the artist to achieve the desired visual aesthetics of the layered glass artwork, ensuring its quality and durability. 

The most important aspects of the monumental, layered, aka stacked glass technique

The process of making monumental and small-size layered glass sculptures is technically vastly different. The small layered glass artwork, which weighs only a few kilograms and is usually planned for an exposition indoors, is only visually influenced by the quality of the sheet glass and the adhesive. On the contrary, in the case of large-scale glass sculptures, it is necessary to consider practical aspects, such as the planned weight of the sculpture, the planned location of exposition (often outdoors), optical tasks to be achieved, the type of adhesive to be used, and the quality of the sheet glass (should be high-quality, completely smooth). Therefore, the creation of large-scale sculptures in the stacked glass technique, which are resistant to a wide range of external conditions while preserving brilliance, transparency and durability for a long time, has only become possible in recent decades due to the progress within the sheet glass production and the chemical industry manufacturing the adhesives. Smooth glass sheets and high-quality glue are the primary conditions for creating monumental layered glass sculptures that are durable in external exposure. Any kind of irregularity, even less than a tenth of a millimetre, in between the sheets of a multilayer object will significantly increase the risk of crack formation. In addition, only in exceedingly rare, exceptional cases can thermally tempered glass be used.

When creating a monumental layered glass sculpture, the second most crucial factor is the choice of adhesive and glueing technique. As in the case of sheet glass, the quality and diversity of the adhesives have dramatically increased in recent decades, thereby enabling the creation of layered glass sculptures suitable for constant exposure under changing external conditions. Likewise, the glue's quality and application technique determine how durable the result will be and whether the visual properties of the artwork will change over time. 

Only rarely a glass glue will be suitable for an outdoor object. Its quality will be an essential factor on which the durability of the entire layered glass object will depend. Therefore, it is necessary to confirm the chosen adhesive's resistance to climatic conditions with the manufacturer so that the glue does not begin yellow, lose its strength, or have any other changes in time. Moreover, it would be best not to rely solely on the manufacturers' specifications since the glue will not have been tested in all the specific conditions of our interest - the manufacturer's technical engineers will confirm this. Therefore, it will be imperative to systematically test the selected glue and its behaviour in various conditions - both in the short and long term. Nevertheless, it is essential to follow the manufacturer's instructions for using the particular adhesive since deviation from it can significantly affect the endurance of the adhered surface.

It is equally important to use an interlayer bonding technique that has been tested in the long term and is suitable for this purpose. For example, while applying quality glass adhesive that meets the required specifications in separate points, lines, or patterns is okay for small layered glass objects, this approach will be unsuitable for large sculptures intended for the outdoors. Due to weather changes, the fixed areas would lose their strength and fail to perform their functions. Layered glass objects intended to be exposed directly under the influence of the environment must be glued in a way that the surface of the glass sheet is completely covered in glue. There are rare cases where minor deviations from this principle are possible. It will depend on the object's shape and whether additional fastenings are used. One must approach the glueing process with patience and precision, spreading the adhesive evenly over the entire surface keeping an eye that the layer of glue does not become too thick. The accuracy of this process can be well observed when placing the subsequent glass sheet on the applied adhesive - the glue must squeeze out evenly on all sides. If the amount is significantly more on some sides and nearly none on others, the adhesive is applied unevenly, thus can cause cracking or even loss of adhesive properties over time.

Finally, a practical tip for developing a visually homogeneous layered glass object is to use glass sheets from the same product batch and factory. The hues of glass under the same name, although they are similar, are not strictly defined. Therefore, the shades will differ among manufacturers and even among different production periods of the individual manufacturer. We can not see this difference when the glass sheets are in the windows or when the batch arrives, but, unfortunately, it becomes apparent in the layered glass object only when it is fully glued. Therefore, acquiring the glass sheets from one production batch with sufficient reserve when making a sculpture is essential. 

When quoting this article, indicate the author, date and website: 

Vitins, Ernests (15/10/2021). "A brief introduction to the layered glass technique - a medium for monumental sculpture making". Available at: https://glasstone.eu/en/articles/about-glasstone/a-brief-introduction-to-the-layered-glass-technique-a-medium-for-monumental-sculpture-making