Mark Smalley. “Words of Clay”

Yesterday,  I tried out some wood ash over a shino glaze and a new ash glaze, which is actually a mixture of a “fake” ash glaze and real wood ash. I was fairly pleased with the results. The teabowl below is glazed with carbon trap shino glaze plus a little mixed wood ash (unwashed) applied to the rim.

I also created a new glaze with the following ingredients:

Nepheline syenite 60g

Whiting 40g

plus one tablespoon of mixed wood ash (raw and unwashed, sieved only).

I only made a small amount for this test firing, next time I’ll measure the ingredients more accurately. This was applied to a biscuit-fired piece of rustic stoneware clay (contains a little iron).  This was the result of firing to cone 9-10 in a saggar:

The following pic is a close-up, which shows the tiny crystals which have formed on the surface. I rather like this effect, which happens when the kiln is cooled slowly.

Fake ash glazes are created by adding large amounts of calcium oxide to a recipe. The base glaze I used above is called “Steve’s Fake Ash” glaze, which I found in John Britt’s excellent text, “The Complete Guide to High-Fire Glazes”. In this case, the calcium oxide comes from the whiting (calcium carbonate).

I’m looking forward to trying this glaze out on a couple of pots in my next firing.

Not long ago, I discovered the fabulous sculptures of  Michal Puszczynski, a ceramic artist who lives in Poland and who also works in France, Switzerland and Korea. Puszczynski creates wood-fired work which he describes as “a bow to Nature”; nothing without it, nothing like it.  He states that it is difficult to explain his own work, and that is understandable when looking at the enigmatic, abstract forms which spring from his hands.

Clearly,  his work is partly the result of close observation of the natural world, of organic textures and processes.  The clay surfaces are split, cracked or wrenched open to reveal pitted, cell-like structures.  Some of his recent sculptures bring to mind notions of fossilised bones, or the scorched and flayed carcasses of mythical beasts. The dynamic way in which the clay has been manipulated gives each piece a life and soul of its own.  One can easily imagine that these objects were once pulsing, breathing organisms, or that long ago, primordial creatures thrived inside them.

Puszczynski’s work is wood-fired in Korean style, tongkama kilns, and it is evident that the method of firing is an intrinsic part of the creative process.  Some of the pieces  look as if they have erupted from within the earth’s molten core, their surfaces ruptured and folded by enormous, geological forces. Other sculptures are cocoon-like forms..ancient, dormant, blackened by fire, but still protective of some unearthly, embryonic entity within.

The following images are from Puszczynski’s recent project, Erosion, where he uses stop-motion photography to capture the gradual dissolution of clay objects.

Images courtesy of Michal Puszczynski

Videos of this work can be seen on Youtube: http://www.youtube.com/user/ErosionProject2009

Michal Puszczynski’s main website with galleries of his sculptural work can be found here: http://www.pottery.art.pl/inside.uk.html

All images copyright of the Artist, Michal Puszczynski

This weekend I tried out a new carbon-trap, shino glaze, adapted from a recipe by Ben Brierley (http://www.ben-brierley-woodfired-ceramics.co.uk/).  I opened the saggar this morning and was delighted to see the glaze on this coffee mug, which shows evidence of some carbon trapping.

Some of the glaze has crawled where it’s been applied in two layers, but where the top layer has cracked in the drying, some carbon has been trapped, creating this interesting, grey crackle pattern. Inside the mug where the glaze is thinner, the shino has developed a typical pinky-red blush.

Next time, I may experiment with smoking unfired pieces after they are glazed, to create a carbonised surface prior to the glaze firing. This could intensify the carbon-trapping effects and possibly allow some control over where the carbon is placed on the pot.

Anyway, I was rather pleased with this piece and even the crawled glaze works to its advantage I think.

“I want to get under the surface. When I work with a leaf, rock, stick, it is not just that material in itself, it is an opening into the processes of life within and around it. When I leave it, these processes continue.”

Andy Goldsworthy is an artist whose work I have long admired. He is a sculptor for whom the natural environment provides his raw materials, his tools and the setting for his work.  For the last thirty years or so, Goldsworthy has been creating unique works of art from found materials such as stones, leaves, petals, twigs, thorns, tree trunks, even cow dung. Pretty much anything that you might find on a walk in the hills of northern England or Scotland may be incorporated into one of his sculptures, many of which are ephemeral, such as those he creates using ice or snow.

“Roof” by Andy Goldsworthy (Image, courtesy of Thom Watson)

Often, his pieces are more like interventions, where he simply incorporates new elements into the landscape, transforming it through the addition of a meandering line of leaves or petals, for example. One of the Goldsworthy pieces I particularly enjoy,  is a dry-stone wall, along the top of which a layer of sheeps’ wool has been painstakingly laid (shown in the Youtube video below). The light is shining from behind the wall and the wool glows like a halo, giving the scene a surreal and ethereal atmosphere.

The image below shows “Stone River”, created for the Cantor Center for Visual Arts, Stanford University in California.  Goldsworthy has said that this piece is as much about the light as it is about stone: “I call it a river, but it’s not a river. The sculpture is about the flow. There’s a sense of movement in the material, through the individual stones, so you just see this line.”

“Stone River” by Andy Goldsworthy (Image, courtesy of godutchbaby)

Goldworthy’s work often reflects the cycles of birth, growth, death and decay in the natural world, and since many of the pieces are temporary, he uses a camera to capture the work at its maximum intensity.  Goldsworthy said recently:  “The ephemeral work is the soul of my art. That is the food. All these other things that I do — the permanent pieces, the installations in museums — are like breathing out.”

Many of his sculptural forms incorporate round holes and enclosed spaces, which evoke multiple meanings. The small round holes (or “oculi”) at the top of the nine domes of his “Roof” sculpture suggest access to shelter, protection from harsh winter elements, or the entrance to a womb-like space. Equally, one may begin to think of ancient burial rituals, the fear and mystery surrounding death, or entrances to spiritual worlds and dimensions. The perfectly round opening he creates within a network of twigs may provoke questions about the nature of existence and the delicate cycles of life on earth.

In many ways, Goldsworthy’s art reveals the miraculous power and mystery of the earth’s elemental forces. But his work also celebrates humankind’s   infinite creativity and the determination to mould nature’s materials into structures which enable us to survive.

Making progress with ceramics can be a slow process of trial and error. To achieve success, one usually has to extensively test glazes and clay bodies and discover which combinations work well at a given temperature. One of the advantages of an electric kiln is that the firing conditions remain fairly consistent, so outcomes are more predictable when you adjust one or two variables.

So far, my saggar experiments have shown me that shino glazes with a high clay content (30% or more) are difficult to fire, and the results are very unpredictable. I’ve had more success with a shino containing a high percentage of nepheline syenite (85%) and a lower clay content (15%). This is probably because nepheline syenite melts at a lower temperature (1170 degrees centigrade) whereas high-clay shinos ideally need to be fired to cone 10 or above.

I opened my kiln late last night after another firing, and was pleased to find the rich oranges and iron speckling this glaze has produced. Well, I thought I would share some of the results here on my blog (more photos can be seen on my flickr page). The pieces shown below were fired in reduction to between cone 9 and 10.

Tea bowl with shino glaze

Tea bowl with shino glaze

Vase with shino glaze

 Simon Leach is the son of David Leach, and grandson of the most famous studio potter, Bernard Leach. As a young man, Simon began making ceramics during a stay on the Greek island of Gavdos, but he served his main apprenticeship as a potter with his father at the Lowerdown Pottery in Bovey Tracy, Devon. In 1990 he left England and travelled to Spain to set up a pottery. Then, in 2003, Simon moved his business to Vall d’Alba, in the region of Castellon, where he continues to make work in Stoneware, Porcelain and Raku.

Stoneware table vase with iron slip and scraffito decoration
(Image, courtesy of Simon Leach Ceramics)

Simon enjoys experimenting with new glaze materials and he often collects wood ash created from the carob and almond trees which grow in the surrounding area. He also goes out into the hills locally to dig for clay which he then processes and refines himself. Like many potters, Simon gets a great deal of satisfaction from creating work which has a direct connection with the earth beneath his feet.

I think I’m probably one of many people who have become quite addicted to watching these clips, partly because we learn something new each time and partly because Simon is such a warm and likeable teacher. I can honestly say that I would have given up the potter’s wheel were it not for his instructional videos, and for that I’d like to say a very big ”Thank you!”. Learning to throw can be a highly frustrating experience, and possibly the biggest hurdle for beginners is learning to fail (again and again!) but to still “get straight back on the horse”. One of the main messages Simon puts across through his videos is that it’s OK to mess up, and that all the failures are an integral part of the learning process. His favourite motto, “Keep practising!” is one which all artists, not just potters, would do well to heed.

More information about Simon Leach and his work can be found at: http://www.simonleachceramics.com/shop/default.asp

Simon’s full collection of Youtube videos are here: http://www.youtube.com/user/sleachpots

The results of my latest  saggar firing were very interesting! I fired two saggars in the same electric kiln, both of which contained combustibles in the form of a few small pieces of charcoal and a small piece of hard wood.  One was sealed throughout the firing whilst the other was only sealed until top temperature had been reached (circa 1260 degrees c), after which oxygen was allowed to enter the saggar during the cooldown phase.

The results from the re-oxidised saggar were disappointing, with no evidence of reduction in the glazes whatsoever. I am wondering if the saggar was properly sealed and maybe oxygen was able to enter early in the firing.

The results from the sealed saggar were much more exciting as I achieved some dramatic iron reds and oranges with the different shinos tested. The three test pieces below have a shino glaze over a “rustic” stoneware body with yellow iron oxide brushed on. The one on the left has the iron oxide applied on top of the glaze, the other two beneath the glaze. 

The recipe for this glaze is:

Potash feldspar    55

Soda feldspar    25

AT ball clay    20

I was really pleased with the carbon trap shino below which was again applied to a “rustic” stoneware body. You can see the difference that the glaze application has made to the colour..the piece on the left was dipped for eight seconds, the one on the right for only three. The recipe for this glaze was adapted from one found on Ben Brierley’s website (http://www.ben-brierley-woodfired-ceramics.co.uk/):

Nepheline Syenite    52

AT ball clay    14

China clay    11

Soda ash    13

Red iron oxide    0.5

This last test piece was the “rustic” stoneware,  glazed with a simple shino consisting of 85% nephelyne syenite and 15% AT ball clay. Before the glaze was applied,  red iron oxide had been brushed on and then wiped off, to leave heavier deposits in the cracks and crevices. The glaze was applied milk thin and is therefore only white in a few areas where it’s pooled. Everywhere else it’s formed matt and satin rust-reds.

Several factors may have contributed towards the improved glaze colours in this firing. The smaller amount of charcoal used may have resulted in a lighter reduction. Also, the inside of the saggar was coated with a wash of red iron oxide. The cooling phase too was much slower, which may have allowed for better colour development.

Recently, I’ve been experimenting with firing pots and test pieces in a saggar. A saggar is simply a large container made of refractory clay which has an airtight cover. Because it’s airtight, the oxygen in the container is burned up if combustible materials are placed in the saggar along with the pottery. This creates what is known as a “reduction” atmosphere, which produces a range of glaze effects which can’t be achieved in oxidation.  For example, a copper glaze fired in oxidation will be green, whereas fired in reduction it may turn a deep red colour.

The kiln I use is electric and a reduction atmosphere can harm the elements. A saggar allows a reduction atmosphere to be created only inside the container, thereby lowering the chances of damage. I make the saggars using a heavily grogged, crank clay which is resistant to cracking at very high temperatures (1200 degrees plus centigrade).  I’ve had some problems keeping the lid sealed (clay seals shrink and split in the firing), so I’m now using a sheet of ceramic fibre blanket with a kiln shelf laid on top. The kiln shelf compresses the fibre blanket, forming a pretty effective seal.

There are two main problems with this type of firing. Firstly, you can’t control the level or timing of reduction as you can with a gas or wood kiln. Secondly, it’s rather inefficient, as the saggar takes up additional space in the kiln.

I have used different combustibles in the saggar, such as wood shavings, straw, and hard wood. At the moment, I am also using charcoal as a way of restricting the amount of smoke produced early in the firing cycle. Charcoal is very effective in removing oxygen but it’s easy to over-reduce with it.

I’m getting some interesting results with shino glazes. These next two pots were fired to cone 10 in a saggar containing lumpwood charcoal and a couple of small lengths (3 inches) of hardwood.

The shino glaze actually comes out a light grey colour with tiny gold specks from the reduction firing. The metallic coppery gold colour is achieved by re-firing the pieces to 1050 degrees centigrade in oxidation (a photo of the cup after the reduction firing is shown in my post “Coiling pots the ancient way”). This is the base recipe for the shino glaze:

Potash feldpsar 33

Soda feldspar 33

AT Ball clay 33

Here are two more test pieces, fired with a similar shino glaze but with approx 0.5% red iron oxide added to the glaze. The interesting effect with these samples is the crazing (created initially in the saggar) which has turned the same copper-gold colour in the oxidation firing.

The test piece on the left is white stoneware, the one of the right an iron-bearing body (the glaze was double-dipped on this sample).

Finally, this last test piece may well be the most interesting. It has the base shino glaze over an iron-bearing clay body. It was laid directly on top of a piece of charcoal at the base of the saggar, but the saggar was fired to cone 10 in oxidation with no lid in place. The exciting thing here is that there was localised reduction of the clay and glaze, but also oxidation, which perhaps produced the rich reddish brown hues in the glaze. The finish on this test piece gets closer to the effects often achieved in wood-firing kilns. Also, the charcoal ash has melted and turned to a dark green glaze on the underside, eating into the clay surface as it sometimes does in anagama kilns.

It appears that the charcoal also increases the temperature next to the clay surface, as you can see the clay itself has begun to blister. This didn’t happen with test pieces placed further away from the lumps of charcoal (and the glaze on those pieces remained oxidised, coming out white in colour).

So far, the kiln seems to be standing up well to these unorthodox methods of firing, but I have no way of knowing yet, how much damage, if any, may be done to the kiln elements. The kiln is fired in an out-building, but in a very well ventilated position. It should be noted that reduction firings produce carbon monoxide,  so safety precautions must be taken with regard to proper ventilation.

The next stage in these experiments, is to find a way to re-oxidise the saggar during the cool-down phase. One possibility may be to use nichrome wire to lift the lid off the saggar during the firing. If the wire could be attached to the lid and passed through the spy hole in the top of the kiln, it may be possible to remove the lid at top temperature.  More research needs to be done into the technical and safety aspects of this option.

I’m also planning to reduce the amount of charcoal in order to achieve a much lighter reduction. More results from this experiment to be posted next week. If anyone has any tips, ideas or theories on this subject, please do get in touch.

Note:  some potters would argue that what I have referred to as an “oxidation” atmosphere is technically a neutral atmosphere, since additional oxygen isn’t being pumped into the electric kiln.  But the term “oxidation” has been commonly  used for all firings which are not specifically reducing.

One of my favourite ceramic glazes is Japanese Shino, which is often used to create wonderful surfaces on ceremonial teabowls.  It’s become very popular with wood-firing potters in the USA, where they now use it to glaze both functional and contemporary, sculptural ceramics. The recipes for shinos are fairly simple, but the glaze itself is usually sensitive to the atmosphere in the kiln during firing. The glaze may also develop colour from the clay body beneath, especially if iron oxide is present. As a result, an incredible variety of colours can be achieved, ranging from whites and greys through to oranges, reds, pinks, buttery browns, even lustrous golds. When soda ash is added to the mix, yet more effects are possible as the glaze may trap carbon and other impurities, creating blacks, greys, crystalline patterns and dappled effects. A potter could spend a lifetime just exploring the potentialities that this one type of glaze opens up.

This is something I have discovered for myself when firing shinos in a saggar (a sealed container) inside an electric kiln. When fired only in heavy reduction, the test samples came out a light grey colour, some with gold specking from the iron oxide. I’ll be writing more about “saggar-fired” shinos in my next post.

Reference:

An artist whose work has been a major source of inspiration for me, is the  sculptor, Ian Gregory. Ian is an extremely talented ceramic artist who has produced both functional and sculptural pieces over many years. He has mastered a wide variety of skills in the field of ceramics, including wheel-thrown pottery, salt-glazed stoneware, life-size sculpture and mixed media installations. He is also an acknowledged expert in the design and building of kilns and often demonstrates his innovative, portable kilns at workshops and exhibitions.

One of the things I like about Ian, is that he recommends learning through experimentation rather than hearsay, and he is happy to dispel some of the myths concerning what is and isn’t possible in ceramics. I remember being astonished at a demonstration when Ian told us that he’s able fire his ”little rocket” kiln to 1300 degrees centigrade in less than 15 minutes (many kilns take at least 14 hours to reach the same temperature)!

 ”Sitting Nicely” by Ian Gregory
(Image courtesy of oakwood ceramics)

Most of Ian’s recent sculptures have been created using paperclay, and he was among the first ceramic artists to discover the unique properties of this material.  If you’d like to learn more about paperclay and Ian’s working methods,  an in-depth article can be found here, on his website. Below are three photos I took in 2006, while he demonstrated his techniques at the “where I fell in love” gallery in Shipston-on-Stour:

Ian uses only a few simple tools to create his highly expressive artworks. His style is immediate, instinctive and fluid and his pieces often have an impressionistic quality.  He has become well known for his sculptures of animals, especially dogs, and he is very adept at capturing both their charming and more menacing idiosyncrasies. Ian has stated that he doesn’t aim for perfect, anatomical precision in his work, preferring instead to try to reveal the essence of things. He creates timeless sculptures which are heavy with latent meaning, objects which may take on a life and reality of their own for each viewer.