Pottery Kilns have been used for hundreds of years to turn clay into firm objects. Modern technology has led to modifications that have allowed the installation of pottery kilns at home. However, these kilns operate at a very high temperature, and you should be careful when using them.
Operating A Pottery Kiln Is Straightforward. If You Aren’t Cautious, Mishaps occur. Here are 13 Tips to help in Using a Pottery Kiln at Home.
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1. Place Your Kiln in a Secluded and Ventilated Place
You must install your kiln in a secluded place because it becomes very hot when you run it. The place should also be dry to avoid corrosion of your machine and possible electrical shocks.
You don’t want your children or pets to go near it. You can place warning signs near the place and teach your kids about the dangers so they don’t become curious and injure themselves. The warning signs will also keep away any strangers or your guests.
The second crucial thing to consider is to place your kiln in a ventilated place or a Vent System. The kiln releases toxic fumes, gases, and other compounds into the air during the heating process. These fumes can be harmful if not removed regularly. Most of the compounds and organic materials burn off between 500 and 1000 degrees Fahrenheit or (260 and 538 Celsius). However, you still don’t want to be hanging around the kiln area while it’s firing.
You can either use a Fume Extractor to transport the fumes out of the room. You can also install your kiln in a place where fresh air can circulate through it. The fresh air will drive out the fumes and help in keeping the temperature lower.
An excellent place to install your kiln would be your garage or basement. If you have a budget, you can also build a small studio with windows. If you cannot afford these, you can place your kiln in your backyard, but you’ll have to be extra careful to ensure the safety of your family and friends. For more detailed information on kiln placement, size and installation, check out Choosing your kiln.
2. Dry Objects Entirely Before Putting Them Into the Kiln
It’s crucial to let the clay dry out thoroughly before you put it in the pottery kiln. If the clay is wet, the moisture in it will evaporate into steam when the heating starts. Consequently, your pottery will explode into bits.
The result won’t only be a waste of your effort, but it can damage the internal lining of the kiln or components like the thermocouple and your heating elements.
Typically, clay takes a week to even a few weeks to get completely dry, depending on the pottery’s size, shape, and climate you live in. Dry clay will be pale in color and will feel dry to touch. For further drying information, check out How Long Pottery Should Dry Before Firing.
3. Wear Protective Gear Before Operating the Kiln
Pottery kilns can reach a temperature over 2000°F (1093°C) during the heating phase, which is why it’s vital to wear protective gear while operating it. Some potters will prop open the lid to vent for the first 1000 degrees Fahrenheit or (538 Celsius) then remove the fire brick that’s propping the lid up and close the lid.
It would be best if you took special precautions when you touched any part of the kiln. Although they have proper insulation, the outer part can still reach a temperature hot enough to melt your skin the moment you get in contact with it.
Even with the protective gear on, you should always try to maintain a distance between yourself and the kiln. For example, it would be best not to put your hands in the electric kiln while it’s on, even with the gear on, because the metal coil and other components can shock you the moment you touch it.
4. Keep the Area Near the Thermocouple Clear
A thermocouple is an instrument used to measure the temperature in the pottery kilns. The manufacturers place the thermocouple so that its tip remains inside the kiln to measure the temperature.
It’s crucial to keep the area near the tip of the thermocouple clear to obtain the correct reading of the temperature. A thermocouple works by sensing the heat in the kiln and generating a small voltage accordingly. It then converts the voltage into temperature.
If the area near the thermocouple isn’t clear and the tip gets in contact with the clay, it’ll show the temperature of the clay’s surface rather than the temperature of the kiln. As a result, you’ll see the wrong readings on your controller’s screen.
The temperature readings give you an idea of the progression of the heating process inside the kiln. If the thermocouple is too close to the clay, it won’t show an accurate rise in temperature and may lead you to believe that your kiln isn’t working correctly.
Moreover, it won’t show you the correct drop in the temperature when the kiln shuts off. It’s important to place your pottery at least 2 inches away from the thermocouple to ensure an accurate temperature reading.
5. Don’t Place Anything Above the Kiln Once It Starts To Run
Pottery kilns generate a good amount of thermal energy. Although it’s well-insulated the outer layer is can still reach a high temperature. That’s why don’t place Anything on top of the kiln while it’s on.
If you think that the excess heat will speed up the drying process of your wet clothes or shoes, you should know that it’s more likely that the heat will burn or melt your accessories.
If you need to use the excess heat for drying your greenware, you can place it near the kiln. It’s best not ever place Anything above the kiln.
6. Don’t Open the Lid and Peek During the Heating Operation
You can prop the lid open about an inch to vent, but you should never open the lid of an operating kiln. Because kilns reach a high temperature during heating, getting in contact with it during this process will increase your chances of being hurt.
Moreover, kilns radiate a substantial amount of heat and light, and it’ll hurt your eyes if you see them without wearing the proper protective gear.
If there’s a situation where you think your kiln isn’t functioning correctly, then shut down the kiln and attend to Anything after it cools downs.
In addition, if you have a top-loading Kiln, you should never open it because as soon as you open the lid, all the heat will escape upwards and burn you in the process.
7. Stay Alert When Removing the Peep Plugs
Pottery kiln peepholes were made to allow the potter to peep at their pottery and pyrometric cones while firing. They also allow the fumes and gases generated inside to flow out. Peephole plugs are responsible for covering the peepholes, and you can remove the top one to let the moisture and the hot gases move out.
However, you have to be very alert and cautious when you’re dealing with the peepholes. Wear your Fire Gloves and Safety glasses, and remember to never stand right in front of the peepholes when removing the plugs.
If you stand too close while removing the plugs, the hot air will drive out of the kiln and straight towards your body which can cause burns and injuries.
Moreover, don’t open all the peepholes because the kilns have to maintain a specific temperature for the clay to turn solid. Opening all the holes for a long time will reduce the internal temperature and can cause your pottery to crack from thermal shock.
8. Use Pyrometric Cones as a Backup To Monitor the Temperature
A pyrometric cone is a tool that you can use to measure the kiln’s temperature. Even if you have a controller that displays the internal temperature, you can use pyrometric cones to see if the controller shows accurate readings. Or used as a backup when the controller or thermocouple starts to malfunction.
Pyrometric cones are temperature-sensitive objects that start to deform at a particular temperature. Each cone has a number associated with it, and each number tells you the deforming temperature of that cone.
To achieve better results, use three cones with different temperature ranges. One cone will bend when the temperature is below the required temperature. One will bend at the desired temperature. And one will deform at the rated temperature and work as a signal for you to stop the kiln. Place near the peephole to peek a look at them.
Using three cones will give you a better idea of the progression of the temperature change and whether you’ve achieved a suitable temperature.
9. Leave Kiln Closed Until the Temperature Is Under 125°F (51.7°C)
Pottery kilns take a day or even longer to complete the whole heating and cooling process, depending on the speed or rate of heating, the size of the kiln, and the insulation. The control screen will give a better idea of the kiln’s internal temperature. However, it would be best to wait until the temperature comes down under 125°F (51.7°C) before you open the lid and see the final product.
You should be cautious even in the cooling phase of the kiln because although the temperature isn’t hundreds of degrees, it’s still enough to get burned.
It’s also better for pottery. If you are removing your pottery with gloves on, then your pottery is still too hot and crack from thermal shock. It’s always best to wait. Nothing about pottery is fast anyway.
10. Don’t Put Anything in the Kiln if You’re Unsure About It
The two crucial reasons you shouldn’t put something in the kiln if you’re not sure about it include:
- The object may not tolerate extreme temperatures and might melt or explode, which will also damage the internal lining of your kiln.
- The object can release toxic fumes when heated, which can be hazardous to your health.
Clay is known to withstand extreme temperatures up to 3000°F (1649°C). It’s this property that makes it possible to heat the clay in a kiln. In contrast, if you decide to use a substance without knowing its tolerance to temperature. It will melt if its tolerance is low or will stay brittle if it has a very high tolerance.
Moreover, some materials release highly toxic fumes when heated due to their chemical composition. These toxins can be dangerous to your health if you inhale them. That’s why you have to be careful when using a material other than clay.
11. Stop the Kiln When It Goes Above the Rated Temperature
Every piece of electric equipment has a rated value of current, voltage, power, and temperature. Rated values are defined based on the tolerance limit of a particular appliance, and you should never operate a machine beyond its rated capacity.
Electric kilns have their rated temperatures mentioned on the serial plate. The value corresponds to the heat tolerance of the metal coils and the thermocouple.
If you operate your kiln above the rated values, the metal coils might melt, or the thermocouple might break. The metal coil and thermocouple are responsible for heating and measuring the temperature of the kiln, respectively. Without these components, your kiln won’t be functional.
Many kilns, especially newer ones, will shut down automatically if the control board starts to overheat. I know the 818 -3 Skutt Kiln that I have will shout down if the control board exceeds 160 degrees Fahrenheit.
12. Regularly Maintain Kiln to Ensure Optimal Performance
Regular maintenance of your kiln will ensure optimal performance and increase the life cycle of your machine.
Vacuum your kiln after every bisque firing to clear out the dirt or other residues that might remain inside the kiln. Also, don’t forget to clean the lid because the remnants on the cover can fall on your ware the next time you use your kiln.
However, make sure the kiln is off, and remove the plug if you can before you start vacuuming.
Moreover, the kiln’s lid is the part that requires more maintenance. When the kiln runs, its top expands during the heating phase and contracts during the cooling phase. This expansion and contraction can slack its band clamps, so you should tighten these clamps occasionally to avoid any problems.
You should also check your plug and socket box from time to time to see if there’s discoloration or overheating. Moreover, you should change your plug if you notice any damage to the insulation of the wire. The damaged insulation can expose the inner copper wire and give you an electric shock if you touch it.
13. Safety Tips to Keep in Mind When Using a Kiln
When you buy a new kiln, ask the manufacturers if they provide the installation services. If not, you should hire an electrician rather than installing it yourself. Home Advisor (affiliate link) is an excellent choice for hiring an Electrician to ensure the safe and correct installation of any wiring, breaker boxes, or outlets.
Installing includes configuring the breaker box, and an electrician will know how to safely complete the job.
In addition, don’t put Anything flammable or temperature-sensitive in the same room as the kiln because they can catch fire if they come into contact with the kiln’s surface or due to the release of hot fumes and gases.
Lastly, always unplug the kiln before working on its components. If your kiln is hard wired, make sure that the circuit breaker has been turned off first if there’s one in place!
Although easy to use, pottery kilns can cause severe damage or injury if you don’t handle their operations properly. For more questions and concerns about using your pottery kiln at home, check out 21 kiln questions Answered
The steps covered above and the safety tips will help you enjoy using your kiln at home without incident.