I often receive messages asking why glazes haven’t come out as expected. There are many variables that can affect the appearance of a glaze; glaze consistency, glaze application thickness, firing temperature, and firing time. We will have a look at some of the most common reasons why glazes sometimes don’t come out as expected.
The most important point is to keep your glaze thickness consistent. I like mine to be thinner than single cream but thicker than milk. Once you have established the consistency that works for you, measure the specific gravity by weighing 100ml glaze and dividing the weight in grams by the volume in ml. The specific gravity of my glazes is usually around 1.4 to 1.5. Every time you make up a new batch of glaze, make sure you add the same amount of water to achieve the same consistency. You can vary the application thickness by immersing your pots in the glaze for longer or dipping several times. If over time your glaze starts to look thin and settles quickly in the bottom of the bucket, it may have become deflocculated. You can correct this by dissolving Epsom salts in warm water and adding a teaspoon of the solution to your glaze. It should immediately thicken as the particles clump together and become flocculated again.
Many glazes are affected by firing either too low or too high. Kilns sometimes fire hotter than the temperature displayed. This can affect surface texture, fluidity and glaze colour. The only way to find out the actual temperature inside your kiln is by using pyrometric cones. These measure the heat work and depend on temperature in the kiln as well as heating rate and soaking time at top temperature. Use three cones placed at a slight angle in a pad of clay. The middle cone should be the one you’re aiming at, with a lower temperature cone on the left and higher temperature on the right, so for example I use cones 7,8 and 9. The two lower cones should bend over so that the tip touches the base but the guard cone should remain standing and determines whether the kiln has over fired. If all three cones bend over, set your kiln to a lower temperature or decrease the soak time at top temperature. I usually soak for 15 minutes.
Inconsistent glaze thickness and firing temperature are the two main reasons why glazes don’t come out as expected. More information can be found my books Colour in Glazes and Special Effect Glazes.
It has been ten years since my first collaboration with Ruth Cross, who designed cosies to fit my porcelain mugs and teapots back in 2006. Since then, we have sold hundreds of cosy mugs and cosy teapots, featured in the press and been copied widely. Our cosy tea sets have sold in London, New York and Tokyo,
Since the Great Pottery Throw Down aired on BBC2, pottery and knitting have become the latest trend, although we dislike the homespun, not-just-for-grandmothers angle on crafts taken by many journalists and presenters such as Kirstie Allsopp.
Ruth has since written a book The Knitted Home and, as well as knitting, also turns her hand to making bespoke shoes with her husband Adam Law. If you feel inspired to knit a mug cosy, the pattern is now available online.
I have really been looking looking forward to this series. The producers had phoned me to ask questions about how long it takes to make, glaze and fire a pot, so I was pleased when they asked me to send some of my pots to feature on the show. I was not disappointed; my nesting bowls were shown in the first ten minutes of the first episode, alongside nesting sets by Billy Lloyd and Daniel Smith.
The format of the Throw Down is similar to The Great British Bake Off. Ten contestants are given technical challenges and one is sent home at the end of each week. The presenter is Sara Cox, who asks questions and shows us how difficult pottery is for the beginner. The judges are Keith Brymer Jones, a production thrower of tableware and singer in clever spoof music videos and Kate Malone, an artist potter who specialises in nature-inspired forms and crystal glazes. Keith sets the technical throwing challenges, while Kate comments on the decoration and design. Keith usually cries once a week when one of the contestants overcomes a particularly difficult challenge. Kate reminds me of art teachers at school, often saying she wants the pots to give her a message.
So far, the contestants have made a set of five nesting bowls, a coil-built wash basin and a set of five raku-fired vases. There have been interesting glimpses of Burleigh transfer-patterned ware being made in Middleport Pottery, where the show was filmed. The programme shows how technically difficult pottery is and how many stages there are in making a pot. Because of the time constraints of the show, pots are often force-dried in the drying room and cracks usually develop. The technician, Rich Miller, has to carry all the pots to the kiln room, pack and fire the kiln. There are interesting snippets from Duncan Hooson of Morley College and Central St Martins Ceramics Design course and Alun Graves, curator of ceramics at the V&A.
I am looking forward to watching the rest of the series. Look out for my tea set in the final challenge.
Harrods magazine have created a beautiful Christmas food feature using my cake stands, plates and platters.
My hand thrown porcelain has been stocked in the Entertaining at Home department in Harrods since July this year. They have cake stands, plates, bowls, jugs and teapots in grey, pink and turquoise. I met the Harrods buyer at Maison et Objet in Paris, where I will be exhibiting again in January 2015. The buyer said they were keen to stock handmade products which were made in England as many of their customers are tourists looking for British made gifts. I actually live in West London only 15 minutes drive from Harrods and even closer to their offices in Hammersmith, so delivering the pots was very easy.
You can read Harrods magazine online. Christmas Food Special Stylists Seiko Hatfield and Emma Marsden, Photographers Tamin Jones and Mowie Kay