Fused Glass Birds

The birds are fused glass. Fused glass is glasswork that's created by heating a piece or pieces of glass to a molten temperature whereby the individual components soften to form a solid piece of “fused glass”. Glass doesn't technically melt as it’s a solid material with no set transition point between liquid and solid. 

 

Kiln Fired

Glass fusing is usually done in a kiln. Depending on how hot you fire the kiln and for how long, you can create smooth or textured glass. A glass kiln has heating elements in the side wall and top of the kiln - unlike a pottery kiln which usually has heating elements only in the side walls. Though some kilns may be fired by other means, my kiln(s) are electric.

 

Fusible Glass

The birds are all clear or coloured glass. No paints or glazes make up the colour, and moulds were used for the shape. All glass is cut by hand. The coloured and patterned parts of the birds plumage are layers of crushed glass!

The raw material the birds are made from is a special type of glass called fusible glass. The glass is less prone to stress, has a more consistent rate of expansion, is suitable for high temperature processes and is generally more expensive! Fusing  different colours of random non fusible glass would make something unattractive and unstable. The fusible glass I use for the birds is made by Oceanside (TM).

Whilst there are companies in Canada that produce sheets of non-fusible or “float” glass (and strictly speaking you could smash this glass up and make some “art"); fusing float glass would be restrictive. You couldn't make colourful birds using ordinary glass unless they were painted. Unfortunately, fusible glass isn't made in Canada, and there aren't a lot of companies in the whole of North America that produce fusible glass. However, I purchase the raw material fusible glass through a Canadian wholesaler.

99.9% of the birds are made from the same brand of glass - Oceanside. I have a few made from Bullseye branded glass. Each brand of fusible glass has its own chemical signature, and temperature at which the glass expands and contracts (coefficient of expansion). If you fuse together glass that isn't compatible, cracks are likely to occur . You also won't be able to control the aesthetics as well.

 

Cutting, Grinding and lots of baths

The shape of The Glass Bakery birds is cut from a fusible solid glass, and the colour  from a fusible crushed glass. The base shape of the bird is hand-cut using a glass cutter. After drawing the bird shape, I score around the pattern using the glass cutter. Breaker-grozier type pliers are used to break off the surplus glass around the bird outline. The bird embryo is revealed! 

After the bird shape has been cut out of the glass, any rough edges are ground away using a glass grinder. The electric glass grinder has a diamond bit which grind(s) the edges smooth.

The glass gets hot as you grind it, so the grinder features a water bath to keep the glass cool and to prevent cracking. Unfortunately, there are no bubbles or wine involved  in this bath.

Once the clear glass shape is cut and ground, the bird needs to be washed thoroughly. if you don't wash glass properly before you fire it, you can end up with a less than glossy appearance. It looks a bit cloudy and undesirable - it's called devitrification. You can google that.

 

After the birds bath time, it's time to colour them with the colours and pattern of the individual bird species. This is the fun bit. The colour is crushed glass. Crushed glass is also called "frit". Frit can be bought or made. Although I have made the frit when I first began fusing glass, I now buy in the glass. A better range of colours are available commercially. It's also less hazardous for the fingers, toes and paws in my household than smashing glass.

Frit comes in different sizes ranging from coarse to powder. My preferred size is powder - which also happens to be the most expensive type. The coloured glass "frit" is carefully applied to the clear glass to build up a picture of the bird and its plumage. It's a bit like playing with sand, but rather than a bathing suit it's recommended to wear a NIOSH 95 respiratory mask and safety glasses! Glass powder is hazardous for the lungs.

The coloured glass is applied to the bird any which way I prefer. Once I've built up the birds plumage colours, it's nearly time to take the layers of glass to the kiln. Nearly. First I need to cut out bird beaks, make some eyeballs from black glass and chop up the metal wire for legs.

 

Firing the birds

Once the bird glass components are gathered and the birds colourised, now it's time for firing! I will have primed the kiln shelf with a glass releasing agent or special silicone based paper to keep the birds from fusing to the shelf. Now the different layers can be stacked on the kiln shelf. It's a bit of a balancing act getting the bird on the kiln shelf. Too heavy footed or clumsy with the hands and the bird layers will slide off before they're fused together. As I'm now working on a wooden floor which flexes, I end up tip-toeing around the room! 

Potters are lucky enough to be able to stack more than one layer of greenware (unfired pieces) in a kiln, and maximise number of pieces per firing. However, the birds are only fired on one shelf to avoid uneven temperatures in the kiln. There also needs to be a gap between the birds as glass tends to stick to each other when it's fired hot enough!

For my perching birds, the metal wire "legs" are sandwiched between the layers. It's not just any metal, but a metal that's compatible with the fusible glass when it's fired in the kiln. If the glass and the metal expanded/contracted at different rates, or the metal melted at a lower temperature than the glass softens, then cracks would happen!

The kiln firing takes at least 14-16 hours plus cooling time, and the kiln isn't opened until the glass has cooled.  Realistically it's around 24 hours or more before the kiln is opened again. Sometimes longer if the ambient temperature is hot and the kiln is slow to cool down. You could fire the birds over less or more time; less you risk cracking, more is arguably a waste of energy.

Those 14-16 hours of firing are split into a number of different segments, or "ramps". The number of segments and temperatures in each segment depends on the fused glass effect you're looking for - slumped, tacked or a full fuse. For each ramp, the temperature cools or heats at a specific rate, e.g. 200 degrees per hour, from 1200 degrees Fahrenheit up to 1500 degrees Fahrenheit. 

It's important to have a ramp in the firing to relax the glass. Heating or cooling the glass too quickly puts it under stress and can lead to a ruined piece. The glass also needs to be annealed which involves controlling the temperature the glass cools down from its molten to solid state. Annealing relieves the internal stresses of the glass and makes it less prone to randomly shattering. Electronic controllers on the kiln allow me to set the speed (degrees per hour) that the kiln heats up and cools down. I can also "hold" the kiln at a particular temperature for a set amount of time. Think of annealing a bit like soaking in the bath. The birds are kiln fused to at least 1400-1450F.

Once the kiln has cooled sufficiently, I either breathe a sigh of relief and smile when I see the birds; or grumble to myself because I failed to get the desired results. If something hasn't worked, it's usually because either an element or relay has broken in the kiln, or because I've rushed the process. Glass fusing has taught me patience! Perhaps not as much as having a large impulsive shepherd dog, but a reasonable amount of patience!

The kiln is then emptied - again using a NIOSH 95 respiratory mask, and the birds are washed. Usually they get a good scrub down.

After firing, hanging birds have a small hole drilled in their head or neck using a diamond bit a water bath and a lot of patience. The bath is necessary to prevent the glass overheating during the drilling process . Drilling glass is not a quick process. Each piece can take up to 2 minutes to drill. That doesn't sound like a lot but the time adds up. When you consider how quick it is to drill a piece of wood, 2 minutes is a long time. The bird sun-catchers dangle from discrete illusion cord (clear thread). Did I mention the birds then get another bath?

If the bird is to be perched on driftwood or a log, each piece of wood is drilled to the correct depth for the new owner simply slots the birds wire legs into the holes in the wood. 

The driftwood was collected along the shores of Nova Scotia, and the logs from the St Margaret's Bay and Annapolis Royal areas. The wood perched are cleaned, cut and sanded on the underside for stability.

I initial each bird on the back - currently using a Titanium pen. The perches are branded.