Project Report - Final Draft - Claire Settle
Introduction
This research explores the viability of using float glass as a sustainable alternative to art- based glass, such as Bullseye fusing glass, in creative practice. The primary aim is to assess whether float glass can be effectively incorporated into fused artwork, thereby enhancing sustainability. Furthermore, the research seeks to evaluate the sustainability and usability of two key construction materials, Jesmonite and Ciment Fondu (art cement), for artistic applications. In this report I shall refer using the term concrete, as it is a product which includes cement as its binding ingredient.
Glass has been a significant material in art and architecture for millennia. Its use has evolved significantly, particularly with the emergence of fuseable glass, which has driven a resurgence in glass art in recent years (Cummings, 2002). Fused glass involves layering and kiln-fusing glass of various colours, textures, and types, contrasting with stained glass, which derives its colour from oxides mixed during the molten stage (Foster, 1999). This distinction highlights the adaptability of glass as an artistic medium, but also raises questions about its sustainability.
Summary
The question of whether glass can be sustainable is central to this research. Initial investigations suggested that fusing float glass might not be feasible due to its industrial design. However, resources such as Glass Campus (Glass Campus, 2023) indicate that, with appropriate kiln schedules and techniques, float glass can be successfully adapted for artistic use. This study builds on such findings to explore the artistic potential and environmental implications of this material.
Over the years there has been a small amount of research in regard to glass sustainability. Historically, the word !window"#derives from the Icelandic !vindauga", that literally means !wind eye". The reason being that up until the 14th Century most windows did not have
glass in them, glass panes started to appear in the mansions of the wealthiest inhabitants of Florence, Venice, Genoa at the end of XIII century. The diffusion process was very slow, and only at the beginning of XIX century in the main European cities, were all the windows glazed, except the ones of the poorest people (Butera, 2004). In the modern age, the majority of buildings have glass within the contract in some form or another. The net result of this, is that there is a need to think about glass sustainably, as according to Cummings A, (2002) the majority of waste glass is not being recycled; but is being dumped in landfills. Glass takes 1,000,000 years to degrade in landfill fully. Therefore the waste glass causes severe environmental pollution threats. Due to the above reasons, researchers have started to investigate the potential for recycling the waste glass in concrete.
Cement/concrete on the other hand has both sustainable and unsustainable aspects, depending on its production, composition, and usage. The production of traditional concrete involves processes such as limestone extraction, which contribute to carbon emissions and habitat destruction. However, advancements such as recycled aggregates and alternative binders like fly ash or slag can mitigate environmental impacts (Scrivener et al., 2018). Concrete production is also a major source of CO2 emissions due to energy- intensive cement manufacturing, though alternative materials can reduce these emissions. Concrete"s durability and longevity support sustainability, by minimising maintenance and replacement needs. However, challenges arise at the end of its lifecycle, with demolition generating waste, though recycling efforts aim to reduce this. Overall, concrete"s sustainability depends on production methods, structural design, and waste management practices. Recent research shows that it is possible to ‘lock away’ CO2 into concrete so making it more sustainable, further, that cement actually absorbs C02 over its lifetime. Wang, Y., Li, X. & Liu, R. (2022)
Jesmonite is a versatile, durable, and lightweight composite material used in construction, architecture, and art. It consists of a gypsum-based powder or micro- cement combined with an acrylic polymer, creating a strong and mouldable material. Developed in the early 1980s, Jesmonite can mimic traditional building materials like stone and wood, making it ideal for architectural details and fireproofing. In art, it is popular for creating sculptures and intricate designs due to its ability to retain fine details. Jesmonite's resistance to moisture, chemicals, and UV light also makes it suitable for outdoor and demanding environments, as well as lightweight architectural projects.
Practical Research Report Methodology
Glass recycling is clearly, an essential part of minimising environmental impact, however reusing glass is an important part of this system. Notably, it promotes energy conservation, reduces carbon footprint, it minimises resource extraction, and finally it preserves material quality (techno-glass.com accessed 24/01/25)
Since 2015, I have developed an interest in the techniques of fusing glass. There are various suppliers specialising in the production of fusible glass which I will refer to as Art Glass. These products are engineered to melt (slump) or fully fuse at specific temperatures. For example, Bullseye glass fully fuses at 804oC, allowing the glass to
Figure 1.
The Float Glass Process
merge. However, the density of the glass varies by colour. This is demonstrated in the accompanying image in figure 1, where mid-blue glass becomes more liquid than white glass during the fusing process. The white frit (small glass particles) is denser and therefore melt more slowly.
Despite using Art Glass for recent projects, I am exploring more sustainable alternatives. Most fusible glass is sourced from the United States, resulting in a significant carbon footprint. As a more environmentally friendly option, I am investigating the use of ordinary window glass, also known as float glass.
The Float Glass Process
The float glass process, also referred to as the Pilkington process, was pioneered in the 1950s by British glass manufacturer Sir Alastair Pilkington. Understanding the differences
between the two sides of float glass—the air side and the tin side—has been termed as ‘crucial’ during preparation and cutting.
During my journey of learning about Float Glass, I had understood that there are various ways to establish which side was the tin side, as apparently it is easier to cut glass on the non-tin side.
In comparison to Art Glass, float glass behaves very differently, and the biggest issue is the way it is made. Molten tin is used as a base to float molten glass, thus creating a smooth even surface on both sides. However, the tin in float glass can be unhelpful when trying to use the glass in artwork although some artists like Jennifer Antonio have managed to make it work to their advantage. Jennifer Antonio looked into the creative possibilities of !bloom,” (when she attended the University of Sunderland) which is a matte film that forms on float glass when reheated above 600°C due to the expansion of its tin-containing layer (see figure 2).
Traditionally seen as a problem in industry and indeed art, the research found that under specific conditions, this expansion can be controlled to create an iridescent effect rather than a matte finish and the glass was found to reflect light. Through creative practice, Antonio developed methods to produce artworks that combined imagery, glass, and light. Her research resulted in a body of eventual artwork, which illustrated ways to use and control these effects for her creative expression. (Antonio 2009).
Whilst this is an interesting side to float glass, my research involves firing pieces of foliage (fern, leaves etc) between two pieces of glass, so any bloom in the fired piece is, at present, undesirable.
For the type of work I wanted to do, it was essential that the bloom effect was not present, using float glass. Frustratingly I came across an issue, and it is this: it is extremely difficult to ascertain which side has the tin content.
How to check for the tin side:
The water droplet method - while this method is fairly simple, gravity can make it problematic. After you clean the glass thoroughly, place a single drop of water gently onto the glass from about 1 to 1.5 inches away on both sides of the glass. (Don"t touch the glass when you drop the water.) Then compare the results. If the
water drop spreads out, it"s the non-tin side. If it stays firm, it"s the tin side.
The UV Light Method - A shortwave UV light can detect the tin side. To use this
method, you need to turn off the lights to the room, then roll the UV light across the edge of the glass. The tin side will glow, the air side will not.
3. Use a multimeter to ascertain conductivity - This is the easiest and most reliable source for detecting the tin side. Simply place the meter on both sides of the glass and the detector will immediately let you know which side is the tin surface.
Despite trying all these methods, I failed to get any of them to work, and thought that I would have to resort to using art glass. Up until this point I had used broken greenhouse glass which was old and very dirty. I had also cleaned the glass with acetone which I regularly use on art glass to remove stains and finger marks. Quite by accident I decided I would need some slightly larger sheets from my local builders merchants, who had offcuts which would otherwise have been thrown away. This was relatively new unused glass.
Objective
This project aims to explore the potential for reusing the damaged float glass through creative practices, incorporating botanical elements for artistic outcomes.
Materials and Preparation
Glass Preparation:The broken float glass was washed using soap and water to remove accumulated organic debris from prolonged outdoor storage. Afterward, the glass was cleaned with acetone to eliminate any residual oils, ensuring optimal conditions for firing and fusing.
Glass Dimensions:Glass pieces were cut to: 1 x 3-inch rectangles and 2 x 2-inch squares
Botanical Inclusions:
A small fern frond and a piece of bracken—both with similar aesthetic properties—were chosen for insertion between two pre-cut 3mm float glass pieces.
Kiln Firing Process
The kiln was programmed using a four-segment firing schedule, optimised for standard bullseye glass initial Ramp: Rate: 222°C/hour to a target temperature of 677°C then a hold time of 30 minutes, Full Fuse Ramp - Rate: 333°C/hour to a target temperature of 804°C hold time of 10 minutes, then the annealing ramp rate: 999°C/hour - this means that the temperature starts to fall at a slow rate to a target temperature of 482°C - hold time 1 hour - controlled cooling: of 83°C/hour to a target temperature of 371°C. Although this programme is specifically for Bullseye glass it worked for float glass, although the float did not melt fully which suggested that the top temperature needed to increase slightly.
The kiln was allowed to cool to below 50°C before opening, ensuring thermal shock was avoided. It is important to allow a kiln to cool sufficiently before opening as this will protect the kiln elements from warping.
Findings/Data
Through my research and experimentation, I have discovered several key insights regarding float glass and the phenomenon of tin bloom:
Impact of Glass Age on Tin BloomOlder float glass is more prone to tin side oxidation, which results in the appearance of bloom during firing.This suggests that the age of the glass could play a significant role in the occurrence of this effect.
Chemical Influence on Bloom FormationThere is evidence to suggest that the use of chemicals, such as acetone, can encourage the formation of bloom.It is possible that a combination of both glass age and chemical treatment intensifies the bloom effect.
Experimental ObservationsThe discovery of these findings occurred unintentionally during the course of material sourcing. After cleaning the glass with warm soapy water, I dried and warmed the pieces using a heater in my workshop. This approach was informed by advice shared on a Facebook group (Glass Fusers UK) suggesting that warm glass cuts more accurately than cold glass.
Comparison of Bloom Formation in New vs. Old GlassWhen the newer glass pieces were cut and fired, no tin bloom was observed on any of the samples.This indicates that newer glass, when cleaned with warm soapy water, is less likely to develop bloom during firing compared to older or chemically treated glass.
These findings highlight the significance of both the age and treatment of float glass in influencing its behaviour during the firing process.
Why do Ferns leave an image when fired compared to other foliage?
I chose the fern as it is a favourite woodland plant of mine and it symbolises the positive effect that the natural world shares with us, improving our state of mind and mental health and this is the primary reason for using these particular woodland plants.I first encountered the concept of firing leaves between glass on a social media platform. Unfortunately, I did not document the details or the creator"s name. It is highly likely, however, that the original maker employed specialist fusing glass (Bullseye). With no prior knowledge of how float glass would behave or how the leaves would interact during firing, I proceeded experimentally. Upon opening the kiln I discovered that the leaves had burned away completely, leaving a detailed imprint of the fern and bracken. Additionally, the float glass had fused together, which was the first unexpected outcome. The second was that, the leaf may have burned away leaving an impression of the original leaf in ash, or, the chemical composition of bracken ash is indeed related to the components used in traditional glass-making, but there are key differences.
Bracken Ash Composition
Bracken ash is rich in potash (potassium carbonate, K2CO3) and other minerals like silicates, calcium, and phosphates. Historically, potash from bracken or other plants was used as a flux to lower the melting point of silica (sand), enabling the formation of glass at lower temperatures.
Glass Composition
Traditional glass is typically made of silica (SiO2), combined with fluxes like sodium carbonate (Na2CO3) or potash, and stabilisers such as calcium oxide (CaO). Modern soda-lime glass, for instance, consists of approximately 70–75% silica, 12– 16% soda, and 10–15% lime.
So there is a distinct possibility that the burning fern has acted like flux within the glass so leaving its image by slightly lowering the melting point.
These findings present opportunities for further exploration, particularly in the use of plant-based fluxes in glass art and production.
Background and Observations:
Several factors could explain why ferns leave a distinct image when fired compared to other foliage, as the leaves burn away, they may leave an imprint in the form of residual ash. This ash could preserve the outline and details of the original leaf on the glass surface. Chemical composition of bracken and fern ash contains minerals and compounds that could react with the glass during firing. The chemical properties of bracken ash closely resemble materials historically used in glassmaking and the presence of this ash during firing was more beneficial to the final result than using a standard leaf I.e. Ivy.
Observations from Jesmonite Research
Jesmonite is made from a combination of ground stone bound with an acrylic/resin binder. The particular type of Jesmonite which I used is AC730 which is more filler/putty like rather than the more popular AC100 which is has a texture like pouring cream, and is suitable for molds. Jesmonite is an attractive pale colour when set, however it was found to have unpredictable qualities. During the experimentation with making the Jesmonite bowls, the following observations were made. In the initial Trials: Vicks Vaporub was used as a resist due to its availability at the time of making. However a notable side effect was that the bowls emitted a strong menthol scent after setting. In subsequent trials Vaseline replaced Vicks Vaporub in later experiments. An unexpected darker hue appeared on the inside of the bowl where Vaseline was used as a resist, potentially caused by mould growth. Analysis suggests that the ingredients in Vicks Vaporub, such as turpentine oil and thymol (a known anti-fungal and antibacterial agent), may inhibit mould growth better than Vaseline.
Potential Incompatibility Between Float Glass and JesmoniteAn additional observation was the potential incompatibility between float glass and Jesmonite. During transportation to an exhibition, the piece of fused float glass inclusion in one of the bowls had cracked. This may have been caused by a differential expansion rate between the materials, particularly when subjected to temperature changes.
Evaluation
Although Jesmonite is a remarkable material, its plastic/resin content makes it unsuitable for recycling. Due to its cost, unpredictability, and plastic composition, I have chosen art cement as the base for my bowls. Cement provides stronger contrast with the fused float glass and offers a grey, brutalist, industrial aesthetic. This frames the clear glass inclusions of fused ferns effectively, symbolising light and hope in mental health.
Having used Cement (Ciment Fondue - Art Cement) last year, I am very familiar with its behaviour. The fact that its carbon footprint is reduced by the recent research (Wang,Y Li, X, & Liu, R. (2022), and its ability to absorb CO2 overtime illustrates that cement is more sustainable than previously thought and is robust in most environments. Ciment Fondue is a product that I foresee moving forward with. as it contrasts well with the blue/green colour of float glass.
Upon reviewing the method of fusing float glass, I can confirm that, it is possible to fuse it in the same way as art glass, with a few heat/fuse adjustments and I confirm as a result of my research that it is a viable alternative to art glass. I will be using it in future work, particularly in the field of fusing fern and bracken into float glass pieces. This project report has enabled me to evaluate the positive aspects of float glass and its use and I am now planning to make a set of four bowls using cement and float glass fused with four different types of English ferns.
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