Let me explain the basic steps of creating ceramic pieces.
Clay comes in plastic bags. I use clay from Greece and also imported clay. Clay from Zakynthos is not suitable for my work as it is low fired (around 700ºC), light yellow – ochre in colour and only good for tiles for the floors and roofs and for big pots to keep olive-oil, wine, cheese and food inside. The clay I use is high fired (up to 1280ºC), strong, mainly white in colour and better for painting.
Although clay is pug-milled from the factory it needs more preparation before we I can use it. The first step is to remove all the air bubbles with special equipment, the pug mill. If I don’ t remove air, ceramics will broke during firing. The pug mill compacts clay and in this way most (if not all) air bubbles are removed. Clay also becomes more firm, more plastic and easier to work with.
Clay comes out from the pug mill in the shape of bars. Clay bars need to be cut in pieces according to the size of the items I want to make. After cutting clay bars to pieces I have to knead clay by hands. Only after thorough handkneading I am sure clay contains no air at all. Kneading is done by special technique called “the bull’s head”. I have to knead each piece of clay for about 50 to 60 times…
Sometimes I have to use flat pieces of clay. For this reason I use dedicated equipment, the slab roller, to prepare and produce small or big flat pieces of clay. These pieces are then cut and pressed in molds or used to make square objects.
To create forms in molds I first make the original piece (a plate, a tile, or any other form, usually flat) and then I make the mold of it, with plaster. Then I can use the mold to reproduce the original. I press clay in molds by hands, as I want my products to be really handmade. That’s why none item can be exactly the same with another. After pressing clay into the mold I have to sponge the inner surface of bowls, plates, and the back surface of tiles to make it smooth and even. Clay must remain in the mold for some time to dry before I can remove it easily without breaking it.
Making ceramics on wheel is fascinating and requires special skills and experience. The most difficult points are the centering of the clay and the creation of tall pieces.
Before putting ceramics into the kiln, when they are dry enough (but not completely) I have to make their surface smooth and even. With special tools and sponge I remove any roughness. Then ceramics are left to dry completely and after that comes the first firing. Time needed depends on the size of the ceramic, on the thickness of clay, on room temperature and atmosphere humidity. You realize that it takes less time during summer time (about 2 – 7 days), but in winter time it may take even more than a month for some big pieces.
After first firing ceramics are ready for painting. First I have to clean all the dust with a brush. Painting is done with special colors, oxides, which are natural colors from the land/earth and are the only colors which can stand the high temperatures into the kilns. Colors change a lot during firing. Usually they become more dark, more strong, more vivid, while some of them change completely i.e. from black to dark green!
After painting, ceramics are left to dry. Then comes glazing. Glaze comes in a form of a powder which I dilute in water in specific concentration. I deep ceramics into the glaze for just a few seconds and then ceramics are left to dry so as to absorb the water and the powder/glaze to cover the whole surface. The last step before putting ceramics in the kiln for the second firing is to take care about all the small marks and make the surface smooth and even.
I use two electric kilns. The majority of ceramics I make need to be fired twice. Each firing last for a whole night, about 10 hours. The temperature for first firing depends on the type of the clay and is usually set from 1050-1250ºC (peek temperature). Then I have to wait for the the kiln to cool down. This usually takes 2 days during summer, when the outside temperature is high. I can open the door only if temperature falls at around 150-160ºC, otherwise ceramics will crack due to the thermal shock. I put ceramics in the kiln in shelves. Care is taken for ceramics not to be in contact with the electric elements.
After first firing ceramics are white and hard like stone but not ready for use as they have pores on their surface. These pores will close with glazing and second firing. During second firing care must be taken so as ceramics will not touch each other in the kiln, otherwise they will stick together. Ceramics look white and you cannot see the painting at this moment because their surface is covered by the glaze. During the second firing it will melt, chemicaly react and stick on the clay, become transparent and let the painting underneath become obvious. Colors are more deep and vivid now.
The glazes I use are lead-free cadmium-free and are dinnerware safe.