are many ceramic firing techniques, some which most people are familiar
with, and others that the layman will never have heard of. This
article is an attempt to create an overview of those various techniques
of firing (the process of hardening and/or vitrifying clay through
heat), that are available to the studio potter and ceramic artist.
This week we start with anagama, black firing, pit firing and raku.
In the next feature we will look at wood firing, salt & soda/vapor
firings and electric firings.
The Anagama kiln will usually consist
of one long firing chamber with a firebox at one end and a flue
at the other. Often there will also be smaller stacking ports on
the side of the kiln. Traditional Anagama kilns are built on a slope,
so that a better updraught can be achieved. Firing time can vary
from one day to several weeks. The Anagama kiln is the oldest style
of kiln in Japan and has been around since medieval times.
The beauty of Anagama style
firing lies in the natural ash glazes that can be achieved,
and in the excitement of the long firing itself, appreciated by
many potters all over the world. There are many different designs
for the Anagama kiln, not only in Japan, but on other continents.
Not only are there different designs, but also different methods
of firing and stacking.
No two firings are ever exactly alike, in contrast to let's say,
the electric kiln.
Amongst the 'primitive' firing techniques you will find the technique
of Black Firing. This method involves
heating a primitive gas-brick kiln to about 1000oC (these
days with gas) and then adding copious amounts of sugar, which then
volatilize and impregnate the clay with carbon, giving it a matt
black surface. Glazes may also be used with this method, which can
result in some interesting effects. The required temperature is
usually reached in about five hours. The gas is then shut off and
flue and any cracks sealed. Sugar is pushed into the burner port
and volatilizes. Then the burner port is quickly sealed with bricks
and fire clay. The kiln cools slowly and can be opened the next
Next Page> Pit Firing