Getting Hooked on Glassblowing

Our current window show celebrates the potential of glass to brighten our lives. Not everyone knows our KSC Manager Julia Donnelly is also a glass-artist. Nowadays she makes glass jewellery – here she describes her journey into glass and the joys of blowing hot glass.

Back in 1985, I was lucky enough to be taken on at Peter Layton’s London Glassblowing Workshop (LGW) in Rotherhithe to help run their gallery and carry out administrative work. I had a strong interest in art but I didn’t know anything about glassblowing. It wasn’t long before I was invited to ‘have a go’ at blowing glass, such was the friendly and relaxed atmosphere in the workshop.

I was hooked immediately. After staying behind a few evenings with Karen Lawrence, one of the women who worked there, I was encouraged to take my making more seriously. I juggled my admin work with glassblowing and was able to assist the glassblowers in the workshop, including Peter.

This is me assisting a glassblower by applying a trail of colour to a work in progress on the blowing iron, around 1988. (Image: Julia Donnelly)

I was very fortunate to learn this amazing skill on the job with some brilliant makers. It was a very exciting time. I left LGW in 1990 to work full-time on glassblowing. I rented Siddy Langley’s workshop two days a week and sold my glass to shops and galleries around the country, including Liberty in London. I also had a stall at Covent Garden Apple Market in the ’90s which was great fun.                                                                                                                 

Playing with fire. What equipment do you need for a glassblowing workshop?

Furnace with a crucible for melting glass kept at a constant 1200 degrees centigrade.

Glory hole – heating chamber for reheating glass during process.

Workbench – bench with an arm at either end for resting and rolling the blowing iron on.

Marver – flat steel table for shaping the glass and laying out glass colours.

Blowing iron – long hollow metal pipe for gathering and blowing the glass.

Pontil iron – solid narrow metal rod used for various jobs including holding the piece towards the end of the process, and for making glass trails as decoration.

Jacks – large tweezers in various forms for shaping the glass.

Annealing kiln (or lehr) – hot glass needs to cool down slowly to let the stress ease out of it. Each piece of glass is put in the kiln which is on all day and then cools down overnight.

Shears – for holding on to the iron where it is hot, and for cutting and trimming hot glass.

How do you make a glass piece? The process.

First of all you need some glass to work with. Molten glass is kept in a crucible in the furnace, which is the heart of the workshop. It is kept at a constant 1200 C. Throughout the day, glass is gathered from it on blowing irons until it is more or less emptied, and then it is time to stop blowing glass. Each day is ended by shovelling glass into the crucible to be melted over night. The furnace is never turned off, unless you plan to be closed for at least a week. Back in the 1980s we used cullet (leftover glass and seconds) from Dartington glass factory that arrived in tea chests. We just had clear glass in the furnace and colour was added to each piece individually. Nowadays, most workshops will use pelletised glass manufactured specifically for studio furnaces, which makes life a lot easier as you don’t have to pick out the odd stones and bits of iron that you will find in cullet.

From my Wave series. Three layers of colour picked up from the marver, plus the yellow chips. The wave shape is achieved by twisting molten glass with tweezers. Acid-etched when cold. I love how the turquoise colour breaks up in contact with the hot glass. Each colour has its own character. (Image: Julia Donnelly)
Peter Layton shaping a glass gather on the marver in his Rotherhithe workshop, with Norman Stuart-Clark. Norman set up his own workshop in Cornwall in the early 1980s. Coloured glass chips are on the marver waiting to be applied to the glass by rolling. (Image: Julia Donnelly)

Gathering glass out of the furnace on the end of your blowing iron is rather like twirling honey on a dipper – but hotter. Much hotter. For a small piece you can gather enough glass with one go. You then roll it and even out the shape on the marver (a metal table).

The blowing iron is, of course, hollow so that you can blow into the glass to create the shape and size you want. Starting the bubble is a skill in itself, needing a fast jet of breath and plenty of heat in the glass. Once your bubble has started, you need to pace yourself so the bubble expands evenly. Another vital piece of equipment alongside the furnace is the glory hole, or heating chamber. As the glass you are working on cools (relatively) it hardens and we need the glass to be hot to be malleable. Every minute or so then needs a trip to the glory hole to re-heat the glass. Turning the blowing iron constantly is something that becomes second nature – as the glass is in a semi-liquid state, if you don’t turn, gravity will make your glass droop.

Shaping the glass – as the bubble in your piece starts to expand it’s necessary to start cutting in at the neck, where the glass meets the iron. Tools called jacks are used for this – rather like a large pair of tweezers. You may pull the neck down if you want a final object with a long, narrow neck or a pulled back flange.

I have heard about the ‘punty’ but not sure what it is.

The derivation of ‘punty’ is from the French for bridge, pont, and Italian, puntilo

When the body of the piece is blown and shaped as much as is wanted, the glass will need to be transferred to the punty iron allowing you to work on the mouth of the piece to finish it. To do this a punty iron is attached to the base of the piece with a small amount of hot glass which works as a bond when attached to the piece. The shock of a drop of water on the mouth end and a light tap with a file will make the glass piece break from the blowing iron while staying attached to the punty iron. The blowing iron is set aside and you continue working on the punty iron heating the neck in the glory hole.

The picture of the punty iron being attached to the main body of glass is courtesy of David Jacobson of Maine, USA. The punty iron will hold the piece of glass when it is unattached from the blowing iron.

The mouth of the piece of glass at this stage will be rather jagged as it has broken away from the iron. Applying some heat to the mouth and then using shears if necessary to cut any large jutting out bits, or just flattening down with a flat tool, you can make a lovely neat neck. Or you can widen the mouth of the piece to make a bowl, using well-directed heat and pressure from the jacks.

Much of the skill in glassblowing is in timing and getting the temperature right for what you want to achieve.

You can sometimes find the mark left by the punty on the bottom of handmade glass, but often it is ground away. I rather like it as it signifies the process.

Adding colour to glass

Most studios have just one furnace which contains clear glass. As many people will agree, working with colour in glass is one of the joys of this medium. Glass colour comes in a variety of forms, can be opaque or transparent. These are just some of the ways of applying colour:

Coloured glass rod – this is rather like a stick of rock and is used for casing colour, where you want an even distribution of colour throughout the piece. A slice of the rod is broken off, heated in the glory hole on the end of the blowing iron and smoothed to cover the end. Clear glass is then gathered over the colour on the iron, and as it is blown the coloured glass expands with the bubble. If you look at the top of a cased glass object, you will see a clear layer around the outside of the piece.

From my Water Garden range the background  is fine powdered opaque celadon, with transparent turquoise/purple and green trails. It has been acid-etched for a matt finish. (Image: Julia Donnelly)

Glass powder and frit – coloured glass is available in various forms from very fine powder similar to icing sugar through fine granules to frit or chips of up to 5mm. The colour is laid out on the marver, and when you have the right amount of glass for your piece, you can apply the colour by rolling the glass in the powder and chips. The colour will melt in to the glass as you reheat it in the glory hole.

Trailing colour – gather a small blob of coloured glass on a separate iron, heat it up and then trail it, as you might Golden Syrup, on to the main body of glass in horizontal, vertical or random ways.

In many cases the colour is applied to the main body of glass before the blowing starts and is melted into the glass. It is possible to add a trail of colour in relief form just prior to finishing, heating it enough to attach it to the glass but without melting it in.

Although I left London Glassblowing many years ago and have worked in various areas, I have kept in touch with Peter over the years. And we were delighted that he accepted our invitation to take part in the first KSC symposium back in 2018 when he came to give a fascinating talk about the history of studio glass in Britain, and his own individual journey. Here he is catching up on old times with Ken.

Ken Stradling and Peter Layton in conversation at the Stradling Collection in 2018

Here is a link to London Glassblowing’s website. You will find a film of glassblowing, and lots of information about the current glass world, which their Bermondsey studio is at the heart of.

I stopped blowing glass in 2000, but a few years ago was introduced to lamp-work glass bead making. I have set up a small studio at home and am able to work with hot glass on this tiny scale, which gives the opportunity to be creative with colour and shape but on a more economical budget.

More to follow about that!

Julia

Go to the Ken Stradling Collection website for more information about the Collection, for details of upcoming exhibitions and how to visit us in Bristol.

This entry was posted in 20th Century Design, Crafts, Glass and tagged , , , , , . Bookmark the permalink.

2 Responses to Getting Hooked on Glassblowing

  1. Pingback: Don’t miss ‘Making Joy: Fire and Ice’ – one more month to visit | Ken Stradling Collection Blog

  2. Helen Alvarez says:

    Julia, thanks for this… great to read about your background in glass and see some of your work. Really lovely pieces.
    I love the shapes and the colours.

    Hope all is well with you.
    Kind regards
    Helen

    Like

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