First published in The Log Book issue 39, September 2009.

Ten Years of Woodfiring
by Terhi Juurinen
My studio – Seenat Ceramics is situated in the small village of Palojoki, 40km north of Helsinki, the capital of Finland. A former farmhouse, the building is still surrounded by forest and fields.

I established the studio In 1976 together with two other eager, recently graduated ceramics artists. Our aim was to produce slip-cast, jigger and press-moulded functional ware in a small-scale production environment. We designed our products together and sold them under the joint name Seenat. This kind of very close way of working collectively was new in Finnish ceramic circles in those days. After five years we were reduced to a team of two – Riitta Siira and myself. During the really busy years our studio worked very well. We had many retailers selling our teapots, square and rectangular plates and bowls, both in Finland and abroad. We also received a big commission to produce 350m of tiles for the main metro station in Helsinki (1981 – 82), which was a difficult but fantastic experience.

After 25 years of production, firing in electric kilns, which is the most common method of firing ceramics in Finland, I found myself in a new situation, as Riitta left the studio in order to take care of her twins at home.

I have always admired Japanese Mingei potters work, especially that of Shoji Hamada and Kanjiro Kawai. I value their magnificent glazes made of local raw materials. The unglazed Bizen ware is also a favourite of mine – the beautiful dark clay, in which you can read about flyash and even how the work was stacked in the kiln. When firing in the electric kiln I tried to achieve similar kinds of effects using coloured slips and ash glazes on my work, but something was missing. The pieces were lacking the warmth and feeling of wood-fired ceramics. I decided that the time was right to make my dream of becoming a woodfirer come true.

I had some experience of woodfiring as a student, while studying ceramics at the University of Industrial Art and Design in Helsinki during the early 1970s. In those days we studied in the Ateneum building by the Square of the main Railway Station, in the centre of the city. Situated in the backyard of this combined Art Museum and Art University, the ceramic department had an old down-draught woodfire kiln, which was fired a couple of times during my four years there. You can imagine how nervous the staff of the museum were during these firings. Luckily all the Finnish national art treas-ures are still to be seen in the museum!

Having left college, I had no further opportunities to woodfire my work, but I began to gather information from books and magazines as well as attending woodfire workshops. In the spring of 1997 I spent two months as an artist in residence at the Cit Internationale des Arts in Paris, and visited the famous pottery village of La Borne in central France, where I saw many different types of woodfire kilns. The following year I had an opportunity to participate in a kiln-building workshop ‘Fireworks’, led by Fred Olsen in Edmonton (Alberta, Canada), during which we built and fired a groundhog type cross-draught kiln.

Around the same time there was an increase in interest in woodfiring here in Finland. A kiln-building workshop was held in Valkeakoski, where I met Mallu Jrkk, a passionate woodfirer and kiln builder. Soon afterwards Mallu designed and built a woodfire kiln for me. The kiln shed was built first and serves as a shelter against the hard climate and also keeps my wood dry. The kiln – a Bourry-box type, with a loading space of approximately 2m, was completed in 2000. As Mallu had built several Bourry-box kilns before, it was a natural choice. In this case she made some alterations to the basic design. In my kiln there is an iron grate in the firebox. Since the kiln was built my excellent firing crew and I have fired regularly three times a year – in spring, summer and autumn. The local sawmill provides us with wood, mainly pine and spruce.

After several experimental firings we have started to fire up to 1250C over two days. On the first day we start at 9am and fire until midnight, by which time the kiln has reached 1000C. After reaching this temperature and maintaining it for a couple of hours we close the kiln down and go to sleep until 6 am. The kiln usually cools down to around 600C overnight, then we continue the firing the following morning. This way the firing is not too strenuous and we are able to enjoy the process. We finish firing at around 6-7 pm on the second day. The kiln is allowed to cool for a week before the exciting moment of unloading.

I have kept a visual logbook by photographing the loading and unloading of each firing. This documentation has helped a lot and means that we do not repeat any mistakes. As I dislike loading in a hurry, the process usually takes about a week. I glaze my bisque fired pieces gradually as the loading progresses.

When I began woodfiring I tested the casting slips used for making pieces to be fired in the electric kiln. The stoneware casting slip worked perfectly in the woodfire kiln and I cast my pieces with the same thickness. However, if the bottom of the piece is very wide it doesn’t withstand the wadding, so instead I use white sand spread thinly on the shelves. Woodfiring gives good results with celadon glazes and beautiful flashings on unglazed pieces. My casting slip contains Hycast VC (which has excellent fluid properties compared to other ball clays) kaolin, and a little bit of Finnish earthenware clay. For my exhibition of bonsai pots in 2006, I succeeded in making a dark brown version of my basic casting slip, and for the copper red glazes I made classic porcelain slip. As stoneware clays are not naturally occurring in Finland, the ball clays and kaolin I use are imported from England.

Earlier I was not interested in ready prepared clays, but now I have tested some in my woodfirings and found one or two good ones, which are especially suitable for extruding. Besides slip-cast work I also make extruded pieces to be fired in the woodfire kiln, which are either shino glazed or left unglazed. I have always liked glaze testing. Sometimes I feel that all my ceramic pieces have been test pieces. The woodfire kiln has given me a new world to enter with reduction glazes. I began with celadons, and experiments with Sang de boeuf was the theme of my latest solo exhibition. Now I am concentrating on shinos.

What fascinates me most about my woodfired results? – In the electric kiln all the pieces in a series look alike. The same forms are transformed into unique pieces by the woodfire process and each piece gains an extra dimension, which appeals to the subconscious.

Ten years have passed quickly and it has been such fun. Now we know how to fire our kiln. These firings have taught me a lot about woodfiring. In the beginning I felt myself very nervous and stressed. Now I am able to relax and follow the rhythm of the firing. We have not made any alternations to the kiln from the start, it looks a bit worn out though, and some repairs will soon have to be made to the adobe insulating layer and also inside the front of the firebox.

With my great firing crew, varying from 2 to 4 enthusiastic wood-choppers, eager to fire, we have experienced all kinds of weather conditions, from summer heat, to chilly winter. We have all enjoyed these gatherings around the fire, cooking and eating delicious meals. The process is very important to us all, it makes us aware that we are a part of nature and is both physically and emotionally satisfying.