One Ash: Tim Thornton
In our latest One Ash blog local ceramicist, Tim Thornton tells us a little about the chemistry behind his process of using wood ash to create beautiful textures and colours to his glazes.
How will you be using the One Ash in your work?
Most of the ash I took is small branches. Now the weather has warmed up and dried out a bit, I will be burning this to create wood ash that I use in my glazes, mixed with some sand and some china clay.
I’m also looking at using some as handles for some of my pots, or as a base to put the pots on to.
Can you tell me a bit more about how you use wood ash in your glaze and how the glaze varies depending on what type of wood you use?
Chemically, wood ash is a mix of metal oxides, primarily calcium but also significant amounts of sodium, potassium, magnesium, phosphor, manganese and iron, plus a little silica. In the glaze, these act as fluxes, determining how easily the clay and silica in the glaze melt. The proportions determine how readily the glaze melts, varying from a high gloss clear glaze to a matt white one as the melting temperature increases.
Some woods also add colour – manganese gives pinks, purples and black, whilst iron can give yellows and browns, or greens and blues, depending on how you fire it. The others also have a secondary effect on the colours. So it’s a complex mixture, and no two batches of wood ash are the same – particularly as the composition varies with the species of tree, the part of the tree, its age, the season of the year and the soil the tree was growing on.
What is your favourite wood to use?
Most of the time I have to take pot luck with whatever wood I can get, and seldom do I get an opportunity like this to get enough wood of a single species. So I generally have to fire with a mixed wood ash.
I’m really interested in your use of wood for imprinting - can you tell me more about this?
What I do is split small logs when green, so the wood has a fractured surface of ridges and hollows. I then cut off the back and shape it into a paddle. Then, once I have the basic shape of the piece, I may beat some or all of it with the paddle to create a surface texture. This also squashes the clay, thinning the wall thickness and changing the shape of the pot as the clay is displaced sideways. This isn’t a problem for me, as I don’t go for strict geometric shapes in my work.
How did you get started with your craft?
About 13 years ago I wanted to do something with my hands, as I was staring at the computer too much in my job, and saw that there were pottery classes at Peter Symonds College in Winchester, run by Sally Bettridge. I went along there and got hooked!
What are you essential tools?
The most important is the kiln. Some of my work is thrown, and I use a treadle wheel for this. But a lot of my work is hand built – most of that is just using my hands, though I may use a rolling pin and some simple wooden modelling tools. Mixing up and applying the glazes needs buckets, sieves, scales and brushes, plus I use some software to keep track of recipes and do the chemical calculations.
Are you noticing a growing interest in traditional crafts at the moment?
Over the last year, during lockdown, I think that many of those lucky enough to have the time, money and opportunity took up crafts to fill the void left by the absence of work or their social routine. And possibly people realising that things don’t just arrive out of nowhere, and the supply chains on which our consumer culture depends are quite fragile, and there is little reserve to buffer disruption, so this may have engendered more interest in material objects.
Over the longer term, I think programs like the Pottery Throwdown and the Repair Shop have created an interest in the crafts, which is good as exposure in the education system and to youngsters is minimal nowadays. But I think that whereas people used to take up an activity and get engrossed in it, wanting to become highly skilled, I think nowadays many more people are wanting an “experience”, so they may go off on, say, a short ceramics course, and come away with a mug to show their friends, but then switch to blacksmithing or flower arranging next time they want to do something creative.
How do you see the future for your craft? What would you say to anyone wishing to get started?
I think the situation is mixed. Almost all university courses teaching ceramics have closed down, or been incorporated into general courses like 3d design or arts courses, which makes it hard for people to get a really good foundation in ceramics unless they are willing to do a lot of reading and studying themselves. But there are lots of people who take it up in their spare time, and a large proportion of potters also teach.
To get started, if you can get in to an evening class or group lesson then that’s good, as you learn by seeing what other people are making and how they are doing it – around me these are available at Peter Symonds on Winchester or at Salisbury Arts Centre. Or to find potters who teach, many in the area are members of the Southern Ceramic Group, and they have a list on their web site.
If you would like to find out more about Tim’s work on his website.
You can read about all the crafters, artists and wood-workers on the One Ash project page.
An exhibition of the One Ash project, including Tim’s work, is planned for 2022 and will form part of the 10-year celebration of all that Andover Trees United has achieved, including the completion of planting in Harmony Woods.