The hidden work of the potter is to open a window for others into the secret working of the mineral world.
At a certain stage, early in the melt of the glaze, while the glass is still receptive to change approximately 1000 degrees Centigrade, the fire is starved of oxygen.
Giving the fierce fire more fuel than it can consume and less air, the fire now turns in on itself and seeks vigorously oxygen from the molecular structure of the materials placed in the kiln.
Then the kiln is coaxed slowly into magical white heat, temperatures in excess of 1340 degrees Centigrade, beyond the melting point of steel, temperatures at which the earth was first formed. Crystals form, colours transmute... Copper oxide normally green turns blood red, iron oxide breaks gloriously into russet reds, fat, waxy, glazes that threaten to spill off the pots populate the finished reduction firing, if successful. If not, the potter returns to the beginning again.
In fuel-burning kilns, firing atmosphere with insufficient oxygen to completely combust fuel, introducing abundance of unoxidized carbon and hydrogen, which extract oxygen molecules from surface of wares, altering appearance of clay and glaze.
These altered appearances can be very dramatic with most of the metal oxides used in the reduction firing at Starways Pottery. Iron oxide usually red-brown to black in appearance transmutes in reduction to tomato/rust reds usually breaking on the high surfaces of the pot, enhancing and showing off the potters gentle throw rings. The iron oxide usually present is ferric oxide (Fe2O3) and the oxygen is then leached from the iron molecule and this becomes ferrous oxide (FeO) which acts as a vigorous flux in the glaze. The colours of the iron substance is now under reduction conditions capable of colouring glazes from pale blue to blue green to olive green and finally black breaking rust colours.
Copper too is greatly affected by reduction cupric oxide (CuO) is usually green under reduction cuprous oxide (Cu2o) can be purple to purple /red and dramatic blood red.
