How To Fire Wild Clay
How to fire wild clay. Firing wild clay can seem like a daunting task, but after reading this article you’ll have a better understanding of how to fire clay quickly and efficiently.
There are many different ways to fire your clay pieces, but in this article we will go over how to pit-fire your pieces so that they are easily accessible to pull out and apply organics too. “Organics” is any organic material that can be burnt onto the surface of the pot. The process of burning organics onto your pieces leaves beautiful black gradients and lines.
Firing wild clay can be a tricky business when first starting out. All clay bodies found in nature hold different properties because of the different mineral compositions found from one place to another. This means that each clay body acts a little different when heat is applied to them. But there are some general rules and guidelines that everyone should know and abide by when firing wild clay.
The first step is to make sure that you have a sufficient amount of temper in your clay. To do this you can fire a test piece before you try firing something important. If you have cracks in the piece after firing, it was probably due to thermal shock. Thermal shock can be mitigated by adding temper to your clay before firing. To learn how to temper raw clay, read our latest article on the subject “How To Temper Wild Clay“. Tempering your clay will help with thermal shock and create a stronger structure overall because the clay particles will have something to bind to.
The second step is to make sure that your pottery is bone dry before you attempt any sort of firing. This means that there is no water left in your pottery piece, except for the H2O chemical bond that will be broken when fired past the boiling temperature of water. Your pot should feel dry, and room temperature, or the temperature of whatever room your pottery piece is in. It will also look ashy and lighter in color. To get a better understanding of these stages read our latest article on the subject “Clay Drying Stages“.
After your clay vessel is completely bone dry, and has been for at least one week, you can begin the next step which is candling your vessel before firing it. Candling is the process of breaking down the H2O chemical bond by bringing the dried clay vessels temperature into waters boiling range. This effectively cooks out all of the chemically bonded water in the vessel before it ever touches a flame. Candling is a crucial step and must be done for a successful firing. To learn the different methods of candling read our latest article on the subject “How To Candle Clay Vessels“
If you have read and followed the “How To Candle Clay Vessels” article, your clay vessels should start looking something like the picture above. They should have absorbed a lot of carbon from the smoke of the fire and should start turning black or darker in color. This is due to the clay pores opening as the clays core temperature raises. As the pores open the CO2 from the smoke is absorbed into the pores giving it gradients of black along the walls of your vessels. This is a great sign that it is time for the firing.
To begin the main firing process you need to have followed all other previous steps. If you have not followed all other previous steps your success rate for firing will be reduced.
To start, simply move the circle of coal and flame until they are surrounding and touching your pieces. Remember to use all protective gear when handling the fire. After moving the circle in as close as you can get it, begin adding on smaller limbs and twigs onto the top of the circle, creating a ceiling of organic materials for the fire to consume.
Eventually this top layer of organic material will burn off leaving you with a lot of embers and a pile of fired pottery pieces! To tell if your pieces have fired, the initial black carbon that was absorbed into your pots should be burnt off now. You should have also notice a change in the clay color. There will still be black carbon spots where your pieces have touched or are still touching an organic material.
Congratulations! You’ve successfully fired your first piece of pottery! You can either let them sit in the fire until cool or pull them out now with your tongs. If you don’t intend to apply organics to them, leaving them in the fire would only strengthen them further. It can however give them more carbon build up on the walls.
If you want to apply organics like horse hair, dog hair, people hair or something else organic to your pottery you will need to keep your pots blazing hot so that they can burn and absorb that organic material. You can do this by making a rack from your charred logs to set your pieces on. This will naturally create a vent that pulls up a strong flame with it. Or if you have enough coal, just submerge your pieces into a coal bed until you’re ready to apply organics to them.
Applying organics to your pottery is a simple process. Just make sure that your pottery is actually hot enough to burn and absorb the organic material being put on. If it is not hot enough, it will not work. Pull your pottery out using tongs and set the pottery down on sand or another inorganic substance that will not burn from the heat. Apply the organics however you like. Some ways of applying could be to drop the organic material onto the clay vessel, or wrap the organic material around the vessel. You could put the organic material on the ground and roll or lay your clay vessel onto the organic material or anything else you can think of. Each has their own effect, and finding what each one does for your pottery can be a fun and enjoyable.
Nice job! All of your hard work paid off, and now you can finally admire your finished work.
