Learning how to fire pottery is an important part of becoming a potter. When you learn how to fire pottery, however, it is important to be extremely careful, since you will be using a kiln that is cooking your pottery at extremely high temperatures. If you operate your kiln incorrectly, you may cause damage to your pottery, your home, or could even burn yourself.
Part of learning how to fire pottery is knowing when you should fire your vessels. Pottery that is fired when it is still wet may explode in your kiln. This is because the water will evaporate within the pottery and then expand as a gas. Without anywhere to go it will cause the clay vessel to explode.
Putting Pottery In The Kiln
Depending on your kiln, you may need to load your pottery from the bottom up or on shelves. Regardless, when you learn how to fire pottery, the steps are the same. Pick supports that are higher than the top of the tallest piece of clay pottery in the kiln’s bottom layer. Put your first layer of pieces on the bottom of the kiln around the supports. If you are firing several pieces, then all layers of pottery should be about the same height. After the first layer is on the kiln, put on your kiln shelf on top of the supports. Keep repeating the process until all of your pottery has been put in the kiln or the kiln is full.
How To Fire Pottery – The First Firing
When you fire your pottery, you will have to pick the temperature and the length of the firing process. The first firing is to turn your clay pottery into bisque wear or “biscuit.” The general rule is to fire your pottery for the first time at approximately 1,750 degrees Celsius. When you fire your kiln you will use clay test cones that melt at various temperatures.
This temperature is referred to as Cone 7, because that is the temperature at which those cones melt. Your kiln has a spy hole so you can see when the cone has begun to bend. Generally you will fire your clay pottery work in the kiln for approximately 18 hours. At this time they will be bisque wear.
The Second Firing
After you glaze your pottery, you will be ready to fire it in your kiln for the second time. This will set the vitreous glaze on your pottery, permanently affixing the glass coating. While it does not matter if pieces touch each other during the first firing, they cannot touch each other during the second firing. This is because they will fuse together when the glaze becomes molten and then hardens.
While the clay determines the temperature of the first firing, the temperature of the second firing, and any subsequent firings, is based upon the type glaze that you are using. Different glazes will undergo the necessary chemical reactions at different times and temperatures.
Related YouTube Videos
Check out the following videos to learn even more about starting this hobby.