The summary of my clay career such as exhibitions, events I have been invited to and my works that are collected by public institutions.
Here you will find some academic writings and other technical notes or just some thoughts.
Log
In this presentation I will talk about an aleatory experiment in my studio that leads to a scientific research and finally to an artistic expression. It started when I got hold of several saggars and played around with them in the firing. The early result is very interesting to me. After a while I could repeat the result and control the effect I wanted. Three years later I formed a research project with material scientists in my university trying to explain what’s happening. The explanation from the research lends to the poetic concept of the work. The visual characteristic from the experiment feeds into my artistic creation and becomes part of the conceptualization. The cycle continues with more and more experiments, research and new expressions.
It started with this saggar. This is a box made of refractory material I got from a closing down factory. I imagine an isolated environment that I could create inside of my kiln, regardless of the kiln atmosphere so I started to play with it.
In a nutshell the technique I am doing is high temperature saggar firing with glaze. Using saggar is not a new concept. Historically the saggars were used in the firing to protect the wares from ashes and detritus in an unclean kiln environment like in wood firing in order to keep the glaze wares inside clean and spot less. However the idea of the isolated atmosphere between inside and outside of the saggar can be flipped. My main firing methods are electric and gas firing which are relatively clean. I use combustible material in the saggar to produce a heavily reduction atmosphere regardless of the actual kiln atmosphere. I end up making it so messy inside the box and have some unconventional effects on the clay and glaze.
There are similar types of firing called black firing or carbonized firing or smoke firing or saggar firing. Which is fired at about (1100 c or higher) ,to have vitreous body color dark gray to black,normally without glaze. The black/ silver of Ibushi tile is created by a special smoking process that takes place at the end of the firing .
For the same reason I have the hypothesis that the smoke reacts to the glaze as well. So i did my experiments with glazed items. The difference I'm trying to make in my firing is to work with glazed pieces and fire a little higher (1280 c) .
My question is “to what extent this firing technique could affect the glaze and how to control it?”
What caught my intention at first was the fact that a lot of things could happen to the very common glaze. For example these two cups are made with commercial transparent glaze on porcelain body. Both were fired in the same firing in an electric kiln. The left one was outside the saggar and the right one was inside(with some combustible material). One could easily predict that the atmosphere inside is reduction because combustion takes place and consumes the oxygen. But there’s also something else happening.
Another evidence of reduction atmosphere in the saggar is explained with the copper glaze. The cup fired inside the saggar turned red.
These are some early experiments that I tried with different glazes and amount/type of combustible materials. After many trials and errors I could control the result and repeat it to some degree.
I chose to work with just a few glazes. In this slide all the pots have the same glazes combination. Varying the thickness and the way they were set in the saggar.
These samples are made with the same clay body and glazes combination. The specimens on the bottom row have a tint of pink which caught my attention too. Later, the research has revealed that it is Almandite- a species of mineral belonging to the garnet group. That is a character I try to repeat in my work later on
One aspect that I try to control is the degree of blackness. Which I do by adjusting by the density of the combustible material in comparison to the space and the proximity of the work to the material.
The factors are : the density of the combustible material -charcoal/wood and
the volume of charcoal (or other combustible materials) in comparison to the space
the proximity of the work to the material (charcoal). I raise the pot with seashells to have the bottom of the pot exposed.
When I observe closer I find an interesting effect in the blackness of the clay bodyr. Although it may seem similar to the blackness you get from raku, pit firing or the smoke firing, the distinction is the sheen. The blackness in the vitreous body is very deep and more glossy. It could be because of seashells. A trace of salt in the shell has fluxed the clay a bit more.
Later on I select just 2 glazes to continue in my works. The two cups were made of the same combination of clay and glaze. I notice that when I layer multiple glazes they bubble. Because of the heavy reduction atmosphere the glaze starts to melt before it has completely de-gas. The gas that tries to escape causes the molten glaze to bubble.
The blistered glaze is regarded as a defect in most cases. But I find it attractive especially with the shiny black color under the blister.
This is how the sagger is set. Please pay attention to the shell at the bottom. I added small pieces of wood too. The ignition takes place around 250-350 degree c. and burns until 950c.
The volume of combustible material in the saggar affects the burning rate. That could also mean that the density prolongs burning rate and affects the glaze longer into the firing.
Fire in the electric kiln to cone 9 or cone 10.
After firing you’ll see that the charcoal and wood has decomposed. Left some ash at the bottom. Shells prevent the pot from sticking to the saggar.
Tap away the blistering glaze. And grind to remove sharpness.
It is possible to control the result to some degree. So that it becomes a composition of light/dark , smooth and rough or having certain character where i wish.
In the box after firing sometimes looks like a disaster. So make sure you protect your kiln well if you build the enclosing space yourself. I use seashells to set my work above the saggar floor and prevent it from sticking to the melted ash at the bottom. The wadding or stilt can be used in a similar fashion.
The shell can be used once. Post firing, after it is exposed to oxygen it expands and crumbles into fine powder. Shell is composed of Calcium carbonate. It turns into Lime after firing.
Listening until now you may wonder about the word Breccia in my title. Breccia is a geographic term that refers to a type of rock. The rock cycle in nature changes from Igneous rock to Sedimentary rock and Metamorphic rock alternately over time, with help of heat pressure and weather. When I took various kinds of minerals and stone and arranged them in a specific way and heated them in my kiln I felt like I was cooking a new type of rock. – hence the borrowed name Breccia–
The distinct blackness in the clay body has caught the attention of my colleague at the university. Together we secured the research grant that allowed us to find out what it is.
The research observes the fabrication of partial black porcelain by carbon diffusion from wood charcoal as a solid carbon source, and the characterization of the body at bottom area.
This is the publication resulting from the research. the research aims to
confirm that the black color on porcelain body can be generated by
carbon directly transferring from wood charcoal.
Samples taken from different parts of the pot.
So we cut up my cups, took samples from different parts and put them through Raman spectroscopy and X-ray photoelectron spectroscopy (XPS). The graphite peak was detected by X-ray diffraction (XRD). This work provides a confirmation of solid diffused carbon from wood charcoal into the porcelain body by scientific techniques.
Although it is not a surprise for us potters who work with smoke or pit firing, raku or anything that makes the body black. We all know that there is some form of “carbon” that makes the pot black. We always relate to the carbon in the form of gas (smoke) that gives the color. The scientists call it chemical vapor deposition (CVD) of hydrocarbons.
What has surprised me is a confirmation of solid diffused carbon from wood charcoal into the porcelain body . This result confirms that one type of crystalline carbon in the product is graphite. The results can be discussed that carbon atoms can directly transfer
from charcoal into cup by the contacting area and the solid diffusion phenomenon play an important role.
the predicting mechanism and
transportation partway of carbon atoms during firing process is
described as follows. Firstly, the gaseous carbon (CO and CO2) atmo-
sphere was occurred by decomposing of charcoal at 400 ◦C . After
that, the carbon atoms in remaining charcoal at the contacting area
diffuse into the cup. They mainly diffuse along the surface and some of
them diffuse along the thickness, and form both crystalline and amorphous graphitic carbon in porcelain body.
As mentioned earlier , I have been selecting and keeping my glazes down to just 2 glazes. One is a commercial transparent and another one is opaque crawling glaze containing Nepheline Syenite and Magnesium Carbonate. No colorant oxide is added. There’s traces of Ferric oxide in raw material naturally.
As an artist I only pay attention to the visual quality. I am happy with matte black, semi-matte black, shiny black, white, many shades of gray, tint of pink, tint of blue/green, the blend between those colors and the tactile texture. All of those I got from seemingly colorless minerals and wood and some shells.
Anyway The pink made me the most curious. My colleague tried to explain with this test.
By taking samples with the pink and without pink color to analyze. Comparing the result they found peak of Almandine only in sample with pink and not in sample without pink color. This is something for further research.
At the end of the day I am an artist working with clay. Every finding fuels into different expressions that I pick and choose for my creation. Visual elements are very important. What do the experiment and the research give to my art?? Can Material and method – lead to conceptualization?
When I ponder over my works I see these things. And I go back and forth with these thoughts.
They sometimes relate to faraway places and a long period of time. To age and to wait…
Can Material expression– lead to conceptualization?
Can the materials have meaning by itself?
I must believe it is possible. Because I keep doing it over and over.
These are some of my works that I try to record time and places with the expression of clay and firing method.
At the end of the day I am an artist working with clay. I keep looking at the world around me. Try to live close to where there’s clay. , kiln, rocks, wood charcoal and seashell. And Making a new pieces of rock from time to time.
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