Evolution of a Pot
Making a piece of pottery is a slow process. Most potters have taken years to develop the skills and knowledge that allows them to craft a piece of art. Unlike the carbon copy pieces you may see at a large store there is no automation involved and every piece is a unique, one of a kind work of art.
To “throw” a bowl on the wheel, similar to the ones you see on my website, you start with a lump of clay. The clay must be free of other substances, dry enough to maintain its shape and strength, while also wet enough to be workable.
Preparing the Clay (3 – 5 minutes)
Preparing or wedging the clay removes any air bubbles that may cause problems later and begins the process of centering.
Center the Clay (5 – 20 minutes)
Centering the clay on the pottery wheel ensures the sides and edges of the bowl will be a consistent thickness and develop structural strength.
Open Up and Lift Bowl (5-10 minutes)
Once the clay is centered you then open it up and lift it to begin forming a bowl out of the solid mound that was created when centering.
Shaping (2-10 minutes)
Once the sides have been lifted and are an appropriate thickness the clay can be shaped to suit the tastes of the potter. Curves, edges and/or straight sections are formed.
Setting Up (several hours to several days)
The shaped bowl is now set aside to begin to firm up and start the drying process. The firm stage is referred to as being “leather hard”. The clay is strong enough to hold its shape and be handled without distorting, but still wet enough to be trimmed, altered or carved. This time varies depending on the air around it. A piece placed in the sun might be ready in a very short time, while one on a shelf in thee pottery studio, with several other wet pieces around it, may take days to get to the leather hard stage.
Trimming (5 – 10 minutes)
Once the bowl has dried to the “leather hard” stage it is trimmed to refine the shape, form the foot and smooth and level the bottom.
Carving and Patterns (5 – 60, 90 or more minutes)
If the potter wants, while the piece is still leather hard, the trimmed bowl can have a pattern, decorations or even holes carved into it. A complex pattern can take hours to carve.
Handles, Spouts, Lips (5 – 15 minutes)
Handles, spouts or lips as well as some decorations are attached once the trimming and carving are complete.
Drying (1 to 7 days)
The bowls is now set out to slowly dry completely. If handles or other additions have been added it is dried slowly so theses additions don’t separate from the rest of the pot.
Fettle the Bowl (2 – 5 minutes)
Once the bowl is completely dry it is often fettled - a process similar to sanding. Fettling will remove any remaining rough edges, small pieces of scrap clay and smooth any small nicks that may have been created while the bowl was being trimmed and dried. Until the bowl is fired it is extremely fragile and will easily break while being fettled if too much pressure is applied.
Bisque Firing (8-12 hours plus up to 12 hours of cooling time)
Once the clay is completely dry it can be bisque fired in the kiln. Bisque firing for stoneware happens at temperatures of between 1800 and 1900 degrees farenheit. Work that was not properly centered or has some other fault may crack on the bottom and have to be thrown out after the bisque firing. After being bisqued the bowl will be hard, stronger, rough but still porous.
Glazing (5 – 60 minutes)
The bowl can now be decorated in one of many ways depending on the look the potter wants to achieve. A piece can be dipped in a combination of glazes (anywhere from 1 to 3 or 4 glazes). Sometimes a piece will be decorated with a series of sprayed on glazes. Often a potter will add a pattern onto the piece in one of many different ways including painting, scraping, screening or hand made transfers. Some decorative glaze techniques can take hours to complete.
Glaze Firing (8 – 14 hours plus up to 15 hours of cooling time)
The final firing in the kiln is the glaze firing which is done at temperatures between 2200 and 2400 degrees Fahrenheit. The glaze will give the colour and finish (shine, satin or matt) to the piece as well as making it capable of holding liquids. Once the piece has been glaze fired it is now vitrified which means it is no longer porous. Most glazes will now be food safe.
There are several different methods of firing, each taking a unique set of skills & materials. Some can be beautifully simple and great for use everyday, while others create complex finishes that aren’t safe for food.
Once the bowl has cooled down after the glaze firing it must be checked to make sure there are no rough spots, glaze imperfections and rough bottoms. Rough bottoms will be sanded smooth, but glaze imperfections and rough spots in the glaze will mean the bowl has to be thrown out or in some instances re-glazed and re-fired.
Up to 25 percent of the pieces a potter starts may have to be tossed out for some reason (crack while drying or being bisqued, broken while fettling, glaze damage, imperfections or just plain dropped and broken).
For most potters however, all this work is worth it, because of the beautiful work that does make it through the process.