Can glass wreaths be made from bottles?
Last autumn a small group within the cooperative Jangling Space decided to see if we could make strip construction glass wreaths for Christmas. This developed out of a collaborative project with Christopher Jeffree on whether bottle glass could be made to fit together at various sizes of frit.
Testing for compatibility of glass at frit levels
It was postulated that small sized frits did not allow stress to build to critical length beyond the frit size. Work is still going on to discover the upper limits to the frit size for this postulation to become invalid.
We speculated that the same brand bottles from the same drinks manufacturer would be compatible. We thought this possible, because there are few bottle manufacturers that can produce the number of bottles required and that they would have consistency. After some experiments with same colour wine bottles we found very inconsistent compatibility. But some volume wine producers use distinctive bottle colours, which seem to have consistency.
After some experimentation we settled on green Gordons gin bottles combined with blue bottles of a reueda wine bottled under the Four Lines brand, both of which had consistency between bottles and production runs and showed acceptable stress levels between them for these purposes. This was important to be able to distinguish by colour the stress between the frit particles. The microscopic investigation of these frit combinations did show incompatibilities, but at very short lengths. The stress between less compatible frits was indeed interrupted by the connection of groups of wholly compatible ones. This was successfully tested in various proportions (25%, 50%, 75%) and sizes from 75 microns to 1200 microns. Testing for larger frits remains to be conducted.
Producing the flat glass
Jangling Space had been producing sheet glass from bottles by analogy from hand blown glass — where the glass cylinder has the ends cut off, and then split — for several years. After experimentation, it was found that cutting out a quarter of the bottle cylinder, the largest piece of flat glass could be made. Of course, we tended toward brighter greens, yellow greens, pale ambers, and various shades of blue. This kept part of the glass pallet inexpensively supplied.
Experimenting for the wreaths
A group of four gathered together to conduct the experimentation and preparing for a wreath making class. Knowing that the Gordons green bottles were consistently compatible, whether as retail or bar sized bottles enabled progress toward using strips to combine into fused objects.
Strips were decided upon because:
it is simple to provide parts for people with no fusing knowledge or experience to assemble,
there is less waste than from shards piled on top of one another,
consistent widths of strips placed on edge would make annealing more accurate,
It would provide a distinctive wreath pattern
We began experimenting with size, arrangement, paints, glues, Frits, glass dots, etc., to provide stability, texture, decoration.
The first element was to establish the principle, so began with small wreaths of about 15cm/6”. These were quick to assemble on shelf paper and we tried sticking them together with CMC. This was messy and required significant drying time before they could be moved. The second assembly test was to use frit to stabilise the pieces. We found we could use thin but relatively stiff plastic sheets to move the pieces on shelf paper to the kiln with little disturbance.
The pieces were fired at a 200°C/360°F rate to 720°C/1328°F for 10 minutes. This temperature was chosen as it is the softening temperature for float glass, which we believed would be enough to stick the glass together without loosing the textures of the radiating strips. We did not use the double thickness for scheduling and annealing as is usual in unevenly thick projects. Instead the pieces were annealed as for 12mm/0.5” although the strips averaged just less than 10mm, but of course there were gaps to be considered.
They came out looking well, and with acceptable levels of stress. But they proved to be fragile when handled. Inspection showed that the wreaths were breaking where the attachment points were small. This led to heaping fine and medium frit over the strips – rather than fitting fine frit between – for the next set of wreaths. It was also felt that the wreaths were pretty dark, so we decided to add clear glass from Gordons gin bottles in a ratio of two green strips to one clear strip. At the same time some of the wreaths had some Bullseye red and white dots added to add more colour. These were fired to 740°C/1364°F. There was little difference in texture of the strips – only a little more rounding – but the frits were more like sand than an enhancement to the wreath. We also found that the clear bottle glass increased the amount of stress, so we went back to all green. The dots showed very little stress, so they became part of the assembly.
Again, although more robust in handling, they were still fragile.
Having learned
frit can stabilise the unfired strips
frits need to be medium to large for a good appearance
higher temperatures are required
only the green Gordons glass could be used
Small Bullseye dots could be sparsely spread over wreaths
We went to a larger scale – 28cm/11”.
Stepping up in scale required a lot more glass – we found two bottles were needed to provide enough strips for a wreath. That is a lot of 75mm/3“ strips! We produced a lot of quenched frit from the bottle necks and bottoms, which required a lot of pounding and sifting, to get rid of the fine and powdered glass. At this scale drawing the limits for the strips became important to maintain the circular doughnut form. Props were needed to keep the strips upright, as many of the cuts were not clean, due to the thickness variations caused by the embossing of the Gordons design on each bottle.
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The essential "sprinkling" of coarse frit for a couple of centimetres (ca. 1”) out from from the centre of the strips was about two layers thick. During the firing most of this sank into the voids between the ends of the strips, and left a "moraine" texture over the internal part of the wreath. It gave an impression of the strips flowing out from the centre, or possibly as a retreating glacier. It provided strength to the vulnerable/weak areas where the sides of the strips contact each other.
This increase in size needed radiating guide lines to keep the strips radiating from the centre, rather than bunching up side by side. More short pieces were needed to fill outer gaps than expected from the smaller trials. The increased size required not only more glass, but a more robust method of transferring the unfired pieces to the kiln. A couple of things were investigated until we discovered pizza shovels. This was ideal to slide under the shelf paper and carefully carry to the kiln. Also more storage space was needed, as not all the wreaths could be fitted into the kiln at once. The minor problems of scale!.
A contour fuse was used to
maintain a lot of the undulations of the glass,
allow some bending over to lower pieces, and
make better contacts and incorporation of the pieces.
These fired well giving a much more robust, although heavy, wreath that was admired by the group and the members of Jangling Space. This reveal of what the group had been doing led to the suggestion of stringing LED lights and ribbons around the wreaths.
In preparation for the hands-on making of wreaths by members of Jangling Space, it was decided to make “statement” wreaths of 38cm/15” diameter. A trial showed that three large Gordons bottles would be required to make them. Also an additional 50% more frit required to be made.
Jangling Space members had to provide and clean sufficient bottles. They were cut and flattened for them, and frit made from the necks and bottoms. Each person had to cut their own strips after being shown that breaking thick glass is easier with cut running pliers without cushions. They assembled and decorated their wreaths and the experimental group placed the frit around the inner part of the wreath. The results were placed on a large pizza shovel and transferred to the kiln, and the waiting ones to storage shelves.
For the class that was subsequently offered, the bottles were provided by Jangling Space members who helped clean them. Members of the experimenting group cut, flattened, cut strips, made frit and red and white balls so each class attender had a set of parts with which to assemble their wreaths. It went surprisingly well.
Thanks to Chris, Linda, Lyndsey and all the others who helped in this project.
