A test kiln is a must for all potters and small manufacturers, even serious hobbyists. Here is why.
A test kiln is a small kiln having the ability to fire to the temperature and firing schedule of your production kiln. It uses on a fraction of the energy. A shelf in a test kiln, the heating of which takes most of the heat-up energy, might weigh 500g. Even a half-shelf in a studio production kiln can weigh twenty times that. Test kilns can fire in a fraction of the time and the controllers on modern devices are amazing.
A test kiln is a must for all potters and small manufacturers, even serious hobbyists. When people are first caught up by the magic of ceramics, they are just happy to make a vase or bowl that does not fall down on the potters wheel or crack on drying. But the charm wears off quickly when large kiln loads of ware are lost due to inexperience, mistakes or unfulfilled expectations with a body or glaze. Later, when customers return ware that is crazing or leaking or leaching or cutlery marking, ability to test is critical.
You may be taken aback by the price, but weigh that against what such a device can deliver. A test kiln, more than anything, determines where your ceramic knowledge and ability will be in a year. Five years. People who only have a production kiln do few tests. Why? Because most tests are failures, in larger kilns that costs money and time!
People with test kilns commit themselves to think more about the technical aspects of ceramics. They learn why things happen. They are likely to be interested in how functional and durable their ware is. They are more likely to know about what bodies and glazes do at higher and lower temperatures, about things like vitrification, density, firing shrinkage, thermal expansion, glaze fit. All by actual experience in firing tests. They are prone to experimenting, to think outside the box, to dream and test the dreams. They see more clearly the infinite universe of techniques and materials that is ceramics. A test kiln makes you independent, able to utilize local materials or mix-your-own own instead of buying premixed. The ability to test will enable you to work at lower temperatures, where more testing is required to find success. It will enable you to develop the ceramic traditions of the area in which you live. Or to experiment with crystalline glazes, translucent porcelain, frit ware, decals, bone china, agate ware, porcelain jewelry, fast-fire, and more.
If you make small pieces a test kiln can be a production kiln. You can even develop a fast-fire process that enables firing it multiple times a day. Coupled with a plaster table and a good propeller mixer, you could be independent and develop and produce a totally unique type of product. If you make high-value pieces a test kiln could be a far more practical production device. Our ConeArt 119 can hold 5 mugs so even some functional ware can be done. Considering that test kilns commonly run on 110 volts, the true practicality for a small scale manufacturer at home can be seen. Imagine what could be done in 3D printing custom-shape refractory setters, this could really maximize the use of the space for a production purpose.
Every potter should have one of these. This one has a separate electronic controller (hanging on the wall behind it), newer ones have it built-in. Start with one of these and then graduate to having a large, second kiln. We have worn out many sets of elements in this kiln, firing it hundreds of times on each set. Ongoing testing is the key to constant development of product and quality.
Red controller on the right: A Skutt Kilnmaster. Blue controller to the left of it: An Orton Autofire. These controllers both attach to a thermocouple in the kiln so they know the temperature. Both are external to the kilns (but there is a big difference). The controllers monitor the temperature change as they turn the power on in bursts, changing the length and frequency of the bursts to control temperature rise. The KilnMaster controller is attached to the 220V power line and the kiln power line attaches to it (there are heavy duty electrical relays inside). The blue Autofire controller connects to the switching mechanism in the other kiln (built to receive it), thus no heavy duty relays are needed within it. The KilnMaster is more flexible since it can connect to any kiln, but it is also triple the price.
This is a ConeArt 119D, 0.57 cu ft, 11"x9" cone 10 test kiln. It only needs 18 amps and runs on 120 volts (although having special plug). We have fired ours hundreds of times, mostly in the cone 4-7 range. The old BX controller is shown here, it is $300 cheaper, but don’t even think about getting that! Get the Genesis GX, that puts the cost at $2285.00. It is economical to fire. Big enough for 5 mugs, but I typically fire a dozen clay and glaze test specimens. We make our own super-thin shelves. It holds about 20 schedules, even controllable remotely (it is Wi-Fi connected). We can fire cone 03 up and down in three hours.