Glass Casting E-Book

Amy Whittingham

• Herausgeber: Crowood
• Kategorie: Lebensstil
• Sprache: Englisch

Veröffentlichungsjahr: 2019

Beschreibung

Glass casting is an exciting and versatile process involving chunks of molten glass melted into a mould, where it solidifies. This practical book explains the glass casting process, from the initial search for inspiration through to simple and then more complex casting. With step-by-step instructions and supporting photographs, it is an accessible and thorough account of this challenging and beautiful process. Topics covered include: advice on kilns and studio equipment; step-by-step projects in open casting, lost-wax casting, part-mould making, burn-out moulds and core casting; ideas for experimentation to increase the scale of your work, explore surface pattern and use other materials; instruction on de-moulding and finishing, and further tips on reusing materials in the studio. Of great interest to glass designers, glass blowers, craftsmen, jewellers, sculptors and interior designers, it is superbly illustrated with 184 colour photographs. Amy Whittingham is a glass artist and sculpture who specializes in mouldmaking.

Leseprobe

GLASS CASTING

GLASS CASTING

Amy Whittingham

First published in 2019 by The Crowood Press Ltd Ramsbury, Marlborough Wiltshire SN8 2HR

This e-book first published in 2019

www.crowood.com

© Amy Whittingham 2019

All rights reserved. This e-book is copyright material and must not be copied, reproduced, transferred, distributed, leased, licensed or publicly performed or used in any way except as specifically permitted in writing by the publishers, as allowed under the terms and conditions under which it was purchased or as strictly permitted by applicable copyright law. Any unauthorised distribution or use of this text may be a direct infringement of the author’s and publisher’s rights, and those responsible may be liable in law accordingly.

British Library Cataloguing-in-Publication Data A catalogue record for this book is available from the British Library. ISBN 978-1-78500-594-7

Photographs by Nicola Simpson except where specified otherwise

Disclaimer Safety is of the utmost importance in every aspect of glass casting. The practical workshop procedures and the tools and equipment used are potentially dangerous. Tools should be used in strict accordance with the manufacturer’s recommended procedures. The author and publisher cannot accept responsibility for any accident or injury caused by following the advice given in this book.

Acknowledgements I have to say a massive thanks to everyone who has helped and encouraged me during the writing of this book – especially to Mark Radford for being a whip, proofreading and generally supporting me in everything I do; my two glass artist buddies Jenny Ayrton and Toni Fairhead, and my mum for proofreading and cheerleading me along too. I have had the pleasure of working with Nicola Simpson, who is an excellent photographer with a huge amount of patience. Most of the photographs in this book have been taken by Nicola, unless otherwise attempted by me. We worked with Zephia Hood, who did some wonderful styling for the flat lays as the chapter openers. I had some incredibly helpful step-by-step testers – Mim Brigham, Pippa Brown, Justine Hadfield, Sarah Pursey (Brown) and Marion Smith – thank you to all of you, and to mum and Brian for being the guinea pigs and loving it. I’d also like to thank all the fabulous artists who lent me books, expressed an interest in testing, helped me, or provided images for the book too; you know who you are. Especially to Angela Thwaites for sharing her ‘mixing with the best’ research, Silvia Levenson for sharing some of her top tips, and John ‘The Pot’ Newton for the story.

To Plymouth College of Art, the University of Sunderland, Pilchuck and Northlands where I have learned so much – keep being those hotbeds of glass education, championing glass art and encouraging others to practise it.

Finally, thank you to Judith Noble and Mark Radford for getting me to commit to actually writing.

CONTENTS

1  FINDING INSPIRATION AND DRAWING

2  SETTING UP A STUDIO

3  MATERIALS

4  GLASS PREPARATION AND KILN FIRING

5  OPEN CASTING AND SLUMPING

6  LOST-WAX CASTING

7  PART-MOULDS

8  BURN-OUTS

9  CORE CASTING

10 DE-MOULDING AND FINISHING

11 REUSING MATERIALS

GLOSSARY OF TERMS

LIST OF SUPPLIERS

REFERENCES AND FURTHER READING

INDEX

Ivy trunk that was removed. (Photo: Nicola Simpson)

CHAPTER ONE

FINDING INSPIRATION AND DRAWING

Generating Ideas

Generating your own ideas for glass casting is like making artisanal bread. It requires patience and time to prove. To develop depth and flavour, for an intense taste sensation, you want your idea to resonate in you. Spark a few of the senses: sight, touch, taste or balance maybe? But to do that you need to let your idea mature. Through step-by-step projects, I will give you the main ingredients and some ideas to get you started. However, working through the projects with your own ideas will be the food that feeds your soul. It will be what encourages you to keep on trying through those times when your cast (or bread!) doesn’t come out as you expected.

My advice on how to generate ideas and find inspiration would be to draw, sketch, paint and photograph. Make models, allow your idea to develop from the first thought that pops into your head. People’s thought processes tend to start in fairly similar places. It is the kneading, stretching and exercising of those thoughts that encourage your own creativity to grow.

Whatever you do, only you can be you. Experiment and allow yourself to make mistakes. Something going awry is an opportunity to learn, and sometimes happy accidents can be the best way to explore these processes and discover your inspirational pieces. After all, the fun part is in the making.

To find inspiration, look in books, magazines and at news stories. I find reading a good source of inspiration as it’s easy to relate to a narrative. You could think about current topics of conversations, or visit museums and art galleries. If you are stuck for inspiration, look at what’s around you, the place, the people and the objects. There is an abundance of inspirational images and forms. If you are not inspired yet, pick something of interest to you and study it. Close your eyes and try to draw it. Failing that, go for a walk with your sketchbook or a camera. Get out into nature.

It could be that you decide to emulate or replicate something you find; this can be a great exercise in working through the processes. The photographs here show a rather big, beautiful ivy trunk growing through a garden wall; someone decided that it would be a good idea to stop this growing but unfortunately that left a gap in the trunk. The gap became an opportunity, a challenge to cast glass in the same shape to fill it.

On a daily basis I walk under a railway bridge. Lots of cars travel under this bridge too. It’s noisy, home to loads of pigeons, and feels somewhat under-appreciated. People travel past, fast, both under and over this bridge on a constant basis. It’s easy to overlook the things we see every day. I love this bridge, the walls, the stone, the moss, the dirt. The water trickling down some of the bricks, the mortar, the blank spaces where there used to be posters. I am inspired by the lines, the tone, colour, texture and forms. Sometimes I am too embarrassed to stop and take photographs of this wall. Instead, I started video recording the wall as I walked past. This way I could replay the journey and gain inspiration and ideas from it. With a lot of drawing, I was able to cast my own glass wall.

Inspiration opportunity: ivy growing through the wall. (Photo: Amy Whittingham)

Brick wall under a railway bridge. (Photo: Amy Whittingham)

In short, don’t be afraid of looking like an artist, you are one! Get out of the house and go somewhere. See if there is anything you notice on the way that piques your interest. If not, when you get there sit and look and draw, look and draw till you get bored of it. Sometimes boredom is where our best ideas come from.

Drawing

Drawing is an essential part of the design process. Even if it is on a scrap of paper or a napkin, scribbling it down will allow you to establish your idea. Think of paper like the sieve for sifting flour; you don’t need to do this but ultimately you get a better end result. Getting a sketch onto paper will help you to consider the form and visualize how this will look in glass. Drawings will also aid with working out how the form may be translated into glass. Drawing or sketching glass is hard to do on white paper. Try using coloured paper and chalk pencils to create the lighter outlines and highlights that glass forms have. This will help when you are translating your ideas onto paper. Remember there’s no pressure for these drawings to be perfect, nobody’s going to be scrutinizing them; they are your way of communicating your ideas with yourself. With practice you will find drawing a natural part of the making process.

A great exercise I did with a class once involved all of us going outside and drawing the same building for a set amount of time; in this case it was half an hour. It was such an excellent teaching and learning activity because everyone was so involved in the task with the little time given, they didn’t get a chance to be concerned about how they were drawing or how good it was. The self-consciousness of drawing was removed and then quickly replaced by another challenge, the time constraint. On returning to the class each person was given a piece of card and a glue gun. Then there were an additional thirty minutes to cut up and create that drawing in model form. This timed activity had the same effect when it came to the model making. Both drawing and model making became intuitive and more fluid instead of tentative and repressed.

TRY THIS

Use coloured paper and chalk pencils or pastels to draw a glass form.

Model Making

Once you have drawn your idea and have a sketch of what you would like to cast in glass, then you will need to make a model. Glass casting differs from most other glass-making techniques as you are not directly manipulating the material. Glass is placed into an investment mould, in a kiln, and is cast into a form. In order to create a mould for glass you need to make a model of the form in another material first. There are several ways you can do this and this is probably the most frustrating part about working in glass casting. You not only need to have a good knowledge of glass but how other materials work too to be able to create forms that you want. The projects in this book will help build a good foundation of glass-casting techniques and model-making options.

Maquettes

As glass casting can be an expensive endeavour, it is good practice to try and work out as much as possible about the final form before you embark on the mould-making process. Make a maquette of your sketch in a transparent material to get an idea of what the shape will look like from different angles, as well as help you to figure out how to cast it into glass. Maquettes will determine whether the form will need to be cast in an open mould, or, if the form is more 3D and has undercuts, whether it needs to be a lost-wax cast or a burn-out mould.

When pitching a design for some awards, I created a to-size model of the final glass award in acetate. This enabled the clients to physically connect to my drawing proposal. The model gave an indication of the size and feel of the design and allowed me to check if the angles and measurements would allow the piece to stand upright without tipping over.

Easy-to-use, transparent materials for maquette models are acetate, laminating pouches, used plastic milk cartons, plastic pockets and some transparent food packaging. If you can create the model with a glue gun or sticky tape and some plastic, it is often easier to translate that form into a master model made out of plaster, wax, rubber or clay. If the maquette is made well then it can be used as your master model to take moulds from. To make a plastic or card maquette more rigid, you can always mix and pour plaster into it. Set plaster when kept damp can be cut, carved, filed and even polished to create completely unique master models. Pouring plaster into a box or old carton will give you a basic form that you can draw on and sculpt.

Master Model

The beauty of glass casting is that your master model can be created in any material. You can use formers in card, wood, modelling clay, plaster, found objects, rubber, Styrofoam, wax, glass… the list is endless. Spend time sculpting and constructing your master model as this will be the object that gets translated into a glass cast through a series of processes depending on the choice of material and intended outcome. Most master models are the positive form. It is possible to cast the space around the form too; this is known as the negative.

Bear in mind that just because a material looks easy to use doesn’t mean that it will be the best one for you to create your master model with. For example, if you would like to create flat surfaces and straight line edges, modelling clay may not be the easiest material to use. Card, glass sheets, acrylic or even plaster can be used to create flat surfaces and straight edges. In the same sense if you wanted to create a fine detailed 3D model, oven-bake sculpting clays are excellent for model-making as you can bake them then cut, file and edit by adding more material and bake again to harden – meaning you can work on all sides of the object without inadvertently squishing the other side.

TRY THIS

As an immediate model-making exercise, take a found object and sculpt a miniature version of it in card or wax.

Sculpt a wax miniature version of a spade.

Positive and Negative Forms

The main thing you will need to note and learn through this book are the materials that can be directly invested to make glass casts, e.g. rubber or clay for open casts and wax for 3D forms (these are covered in the next few chapters), alongside the materials that need other part-moulds making of them to be translated into wax and then invested. As you are making moulds from master models you can also use these materials – plaster, rubber and wax – to work through positive and negative versions of the master model.

Here are two examples to illustrate how this has been used:

Rockpool, positive rocks and negative pool. (Illustration: Amy Whittingham)

1. Imagine a rock pool. You could cast in an opaque glass the texture of the rocks in a bowl form, creating a positive of the actual rocks. Or you could cast in clear glass the water in the pool itself, creating a cast of the negative space in the pool.

Positive hand and negative space around the hand. (Illustration: Amy Whittingham)

2. Imagine you want to cast a set of hands. You could cast the hands in glass or you could decide that you would like to cast the space around the hands instead. Both of these options would start with the positive hands, then a skin-safe product is used to create a negative mould of them. From this point, the materials you choose to use in the negative mould can be altered. The materials you use depend on whether you are creating a positive version of the hands using wax or a negative cast of the space around them, which could involve using rubber, plaster or investment.

I like to think of it like this: I am either casting the positive form or I am casting the space around the form, which is known as the negative. This can be confusing as essentially each form is physically positive. Don’t worry though, the distinction will become evident as we work through the projects in the book. First things first: in the next chapter are some of the basics for setting up your own glass-casting studio.

Flat lay of health and safety kit. (Styling: Zephia Hood and Nicola Simpson)

CHAPTER TWO

SETTING UP A STUDIO

The Basics

Glass casting has the potential to be a bit of a messy business. Having a designated space to make moulds and handle glass in makes casting that much easier. Setting up a studio can be simple, and knowing what materials you are using and having the right personal protective kit to wear means at least you are not putting yourself or anyone else in harm’s way. These are the bare minimum requirements you need to be able to create your own studio for casting glass. After discussing these I have also covered some of the bonus items, which are not essential straight away but are luxury extras to aim for. If you have a bit of space and can get access to the four below, you are pretty much good to go on your casting adventures.

• A kiln

• A level surface

• Extraction or ventilation

• Water and drainage system

A Kiln

A kiln is an insulated heating chamber (like an oven) that is capable of going up to temperatures of around 1,000°C (1,832°F). Kilns are available to buy new and old. They do crop up on online auction sites occasionally, so keep an eye out and do your research. Don’t despair though – it isn’t essential to have your own kiln. If you don’t already have your own, you may find that it is worth contacting local glass makers or artist’s studios to see if they hire out space in their kilns. This way you can determine which type of kiln would be good for the glass projects you like to do without that initial expensive investment.

Kilns can be used for firing glass and ceramics, although some glass kilns do not reach the higher temperatures required for ceramic firings. I have mentioned this because unless you are melting your own glass from the raw ingredients, you will not need your kiln to fire up to temperatures this high. The top temperature range required for casting glass, using all types of ‘ready-made’ glass from bottle glass to Bullseye sheet glass, is unlikely to exceed 900°C (1,650°F). I have an old ceramics kiln that has heating elements around three sides, which works perfectly well for the glass-casting projects I do.

Front-loading glass kiln at Plymouth College of Art.

Kiln controller at Flameworks Creative Arts Facility.

Investing in a programmable kiln controller is definitely necessary if you want to use your own kiln. Essentially all types of kiln can be used for glass casting as long as they have a programmable controller. The controller and therefore the programme or ‘firing cycle’ is potentially more important than the kiln in terms of your glass-casting success. This will be covered in more depth within each project, but the firing cycle is used to control the rate of temperature change, so as not to shock and crack the glass as it heats and cools. It may not be obvious when you are thinking about purchasing a new kiln, so double check that it comes with a controller included as some are sold separately.

A lot of glass-fusing kilns have heating elements inside the lid. The heat from the top allows an even surface on a flat piece of fused glass. Great news, these fusing kilns, known as top loaders, will work for shallow open glass casts and relief moulds. Due to the internal height of these kilns, they may also work for some of the deeper casts, but it is advisable to take measurements before you make any moulds. Measuring the internal dimensions of your kiln is good practice anyway, as you really don’t want to go all the way through the mould-making process only to discover that your mould will not fit in your kiln. Take a couple of centimetres off each dimension to ensure that there is still sufficient air flow around your mould within the kiln.

Top-loading glass kiln at Plymouth College of Art.

If you are interested in casting deeper moulds, then a front-loading kiln or deep top-loader may be better for you. These taller kilns have elements that are built into the walls of the kiln and sometimes also in the base. Generally, these kilns will provide a more even temperature for lost-wax and larger casting projects as the heat can penetrate the mould from around the sides, not just the top down. Some kilns may require test firing to determine whether the temperatures need to be adjusted to make allowances for where the heating elements are.

If you are really struggling to find access to a kiln and just want to get started with some of the smaller casting projects for jewellery, then a bead annealing kiln may be the answer. I have a Kilncare one which is tiny but I love it because it has a no-fuss, single-phase 3-pin plug, which can be used at home, and has a controller built-in which is programmable. It has four programmes, where you can amend and store firing cycles to suit your purposes. I use this frequently for small open casts, burn-outs and lost-wax cast jewellery pieces. It’s a great starter kiln as it is so versatile in its uses, from annealing glass beads in lampwork to glass fusing, slumping and casting. I have a friend who even uses hers for enamelling on metal and firing precious metal clay.

Top-loading ‘coffin’ kiln at Plymouth College of Art.

A level table.

A Level Surface

This seems like a really obvious and essential item to be talking to you about, but I found out the hard way how necessary a level working surface can be. Make sure your table top or side is stable and level. An uneven surface can adversely affect any moulds you make and therefore the depth or evenness of the glass you cast into it. This is particularly evident when making open cast moulds. Sometimes this can be corrected in the kiln but it can be a time-consuming step in an already complicated kiln-loading process.

You will need a table with an easy-to-clean surface. Wooden tables will need oiling to create a barrier on the surface in order to make it easier to clean mould materials and spillages off. You can use anything from linseed oil, which can be expensive, to WD40 to coat the table. I recommend working on plastic or wooden boards (old chopping boards are great) as you can pick them up and clean them with ease and move whatever moulds you make out of the way without disturbing them. I have an additional board that is the same size as my table with carpet glued to one side so that I can easily get this out as a glass-cutting surface and store it out of the way when I am finished. Carpet tiles are also great for this. If I am making a lot of moulds or using silicone that is particularly messy, I will cover the work surface. Thin plastic sheeting or old lino stuck down underneath with gaffer tape works well.

Extraction.