Skip to content

Glass Fusing

I had such fun last year glass blowing that I thought I’d try another glass-related craft. After quite a bit of searching online, I found a one day course on glass fusing and slumping, hosted by Rainbow Glass in Stoke Newington, North London. It sounded intriguing, so I signed myself up for the one-day course for complete beginners.

The course was last Saturday, and it was absolutely fascinating! Much less technical than the glass-blowing course, and all the students’ input was done very firmly at room temperature. Glass fusing is all to do with layering pieces of different coloured glass on top of eachother, which are then heated in a kiln overnight to ~850ÂșC, at which point the layers fuse together. A second firing in a mould completes the process – the glass then “slumps” to form the desired shape – a bowl, ash-tray or whatever. It’s actually a pity that nobody on my Christmas list smokes, as I suspect I’ve ended up making a series of small ashtrays!

There were six of us on the course. The other five were more artistic than me, and had all done at least one course on Stained Glass in the past. I was a complete beginner – my one day of glass blowing had no relevance or carry-over at all! We started by learning how to cut glass, both in straight lines and (much more difficult!) in curves. We used tools to score the glass, then tapped it to create a fracture all the way through, before snapping it apart. The tutor made it look very easy – it wasn’t! We practiced on offcuts of glass that he got from the picture-framers on the other side of the courtyard, so that we didn’t waste any of his expensive art glass. I found it very difficult – for a start, I’m left-handed, so had to try to mirror everything the tutor was doing. And I’m short and not particularly heavy, so it was difficult for me to apply enough downward pressure on the glass. That was solved by standing on a wooden box to help me get the angle right! When you’re doing it correctly, the scoring tool makes a very satisfying crackling sound as you trace out the shape of the cut you want to make.

Once we were relatively competent at scoring and cutting glass, we were given a lecture on all the different techniques we could try. The basic idea is that semi-molten glass has a surface tension which means that it naturally tries to make itself 6mm thick. So if you start off with a 3mm thick piece of glass it will contract, and anything over 6mm will tend to expand. Each of the sheets of fusable glass was 3mm deep, and the idea was to have two layers on average over the area of the bowl. However, you could add more layers on top, put inclusions (e.g. bits of metal) in between the layers, or shape the underneath with fibre wadding that burned away in the kiln.

We were then given a sheet of paper, about 45cm square, and told that was the area we had to play with. We had to draw out, in advance, what it was we wanted to make. My mind was buzzing with all the possibilities we’d been given – there was almost too much choice, and I resolved to keep things as simple and abstract as I could! The tutor cut out the bases for us – either circular or rectangular (the glass is expensive, and he didn’t want rank amateurs making a mess and wasting a whole sheet!). We then decorated the bases with coloured glasses which we cut according to our pre-planned designs. We arranged the cut glass shapes on the bases, and when we were happy with the arrangement we tacked them in place with small drops of an organic glue that will burn away in the kiln.

Six glass bowls waiting to be fired in the kiln

Six glass bowls waiting to be fired in the kiln

Above you can see a rather blurry snap of my six pieces in the kiln. I’ve stuck to a pretty basic palate of blues, aquas and greens. You can’t see from the photo, but the top small square of glass is sitting on top of some abstract shapes made from fibre wadding, so should flow over it when heated and take on the impression of the fibre shapes. That’s the idea anyway. The others should be more a case of “what you see is what you get”. However, I’m not personally going to see them for several months – I’ve asked for them to be packed up and posted to my parent’s house, to be unwrapped next time we’re all together as a family – which probably won’t be until the New Year.