6 Common Electric Kiln Questions

1. What are elements and how long do they last?

Elements are essential components responsible for generating the heat necessary for firing pottery and ceramics in a kiln. The heating elements in most studio style or top-loading ceramic kilns last about 100 to 150 firings. This can vary depending on how high in temperature, how fast, and what one is firing (bisque, glaze, or both). Good kiln venting also has a positive effect on element life. Most schools who have dedicated, busy, ceramics programs will get about 2 years out of a set of elements in their kilns or more. It is not uncommon for heavy production studios to change elements as quickly as every 6 months. Less frequently used kilns’ elements can last many, many years. Elements should always be replaced with factory units.

Now, we do see elements from time to time with over 250 firings on them. This is not typical and these rare kilns are always low-fire only, vented, wax free ware, and in private studios, among some other rare but perfect firing conditions.

2. What are relays and how long do they last?

In a digitally controlled kiln, power relays are electronically controlled switches. The kilns digital controller tells these switches to turn on or off at certain rates/intervals/times to achieve certain parameters/temperature goals that are programmed into the kiln’s controller. That clicking one hears when the kiln is firing is the 12-volt relays turning on and off. Relays, like elements do a lot of work, they typically last about the same amount of time as a set of elements. There is typically one 12V power relay per section of kiln, i.e. 3 section kilns have 3 relays. It is good practice to change both relays and elements at the same time.

Most top-loading kilns have 12V relays, some have mercury relays, large contactors, or relays for higher voltage or higher amperage. These are not interchangeable. Like elements, factory parts are best.

3. What is a thermocouple and how long does it last?

A Thermocouple can be described as thermometer for high temperatures. They are made of metal and ceramic components and typically last about 75 firings. A kiln will often need to replace its thermocouple(s) once between element changes and again when the elements are replaced.   

4. Can wiring get damaged from the excessive heat?

It’s not uncommon for the wiring and electrical components in kilns to get damaged by the high temperatures that they are subjected to. High-temperature wire insulation corrodes,  connections loosen from heat expansion, and terminals deform and break – these are all common occurrences in kilns. These components should be replaced at the first signs of damage or wear to prevent dangerous arcing or other catastrophic failures or safety hazards. These parts and materials are usually specialized and specified for high-temperature applications.

5. What is the serviceable life expectancy of top-loading electric kilns?

Generally this answer falls into 2 categories- Schools/institutions and private studios. Manufacturers and AKS typically agree that most kilns in most schools will last about 15 - 20 years if properly maintained. This will depend on multiple circumstances, and adequate service. Some schools will get less than 15 years out of a kiln, and some will get slightly more. As a general policy AKS does not suggest any manually controlled kiln (“kiln sitter” kilns) be used in schools.

Private studios can get longer out of a kiln than 20 years with proper maintenance and inspection. We have repaired kilns that are very old. Circumstances matter a lot. Generally speaking, we do not recommend putting old discontinued technology (old kilns) in your home. If your kiln is in an outbuilding or dedicated, detached, studio space, it is likely that we can fix it no matter how old.

6. Why do you suggest annual inspections?

Inspections are relatively inexpensive, and essential. These pieces of equipment regularly fire to, or far beyond 2000 deg (F), over and over, and over. Kilns should be inspected annually and serviced at the first signs of malfunction or concern.  Doing so will ensure most kilns will safely last 15-20+ years with even heavy use. You can read more details on the importance of inspections here.