I use 3 different kinds of clay.
Air drying clay is used for children’s sessions where a more immediate result is favourable. This doesn’t need fired and can be taken home to dry and paint with any paint… from cheap poster paint.. to acrylics. Then if wanted, it can be varnished or covered in white pva glue(which dries clear). This option helps to strengthen the piece and gives a light sheen. Air dry clay is purely decorative so can’t be used for food or liquid.
Earthenware clay and stoneware clay are also used. Stoneware is fired much higher so is on the whole stronger and better for tableware while earthenware is fired a bit lower and better for decorative or light use.
The process of ceramics is a long one so not for the impatient.
Once clay is bought it needs to be weighed to suit the task and wedged(kneaded) to remove any trapped air.
After it has been made into its finished shape it can be decorated with underglaze or slips. This is basically coloured clay that’s watered down like thick paint. Or it can be left plain and decorated later with glazes. It is then dried thoroughly before going in the kiln. As a kiln is expensive to run, it’s important and economical to only fire once it is full. This adds to the long timescale of pottery. Earthenware is fired over 10-12 hours to reach a temperature of around 1000C while stoneware is fired to around 1250C. Then it has to be left to cool for 12-24hrs before opening the kiln.
TORTURE FOR A POTTER HAVING TO WAIT!!!!
Once cooled pieces are now ceramic and vitrified(all water removed) & will never be clay again. Up until firing clay can always be recycled for using again.
This is the stage pieces can be glazed if required which makes pieces waterproof. Glazes are basically liquid glass so need to be handled carefully as glaze dust can be very harmful if inhaled.
When the glaze is dry it then goes back in the kiln(this time extremely carefully with no glaze edges touching shelf, sides or other pieces or glaze will fuse to whatever it touches!)
Another long wait for firing and cooling before you can eagerly open the kiln to reveal your finished masterpiece!