Kilns, particularly electric kilns, are fired to high temperatures to harden and transform clay or other materials. While various types of kilns exist (like gas or wood-fired), the reference provided focuses on electric kilns.
Firing Electric Kilns
According to the reference, there are three common ways to fire an electric kiln. These methods involve carefully controlling the temperature increase and duration to achieve the desired result, often guided by indicators like pyrometric cones.
Here are two of the common methods for firing electric kilns described in the reference:
1. Manual Firing with Cone Observation
- Process: This method requires constant monitoring. The user manually turns the kiln on and gradually increases the temperature settings.
- Temperature Control: The firing progress and temperature are determined by watching pyrometric cones placed inside the kiln. These cones are specially designed to melt and bend at specific temperatures and heatwork.
- Monitoring: The user observes the cones through a small opening called a peephole in the kiln door or wall.
- Completion: When the cones indicate the desired temperature and heatwork have been reached, the user manually turns the kiln off.
2. Manual Firing with a Kiln Sitter
- Process: This method also involves manually starting the kiln and turning up the heat. However, it utilizes a mechanical device for automatic shut-off.
- Automatic Shut-off: A device called a "kiln sitter" is used. This mechanism holds a small pyrometric cone, specifically a "junior cone."
- Temperature Control: As the kiln reaches temperature, the junior cone within the kiln sitter softens and bends.
- Completion: When the cone bends sufficiently, it triggers the kiln sitter mechanism to shut off the power to the kiln, ending the firing cycle. This method offers a degree of automation compared to constant peephole observation.
Summary Table:
| Method | How it's Controlled | Shut-off Mechanism | Monitoring Required |
|---|---|---|---|
| Manual with Cone Observation | Manually turn on/up, watch cones through peephole | Manual shut-off based on cone observation | Constant |
| Manual with Kiln Sitter | Manually turn on/up, use junior cones in kiln sitter | Automatic shut-off triggered by cone melt | Less constant |
The reference mentions a third common way but does not provide details about it. Modern kilns may also include programmable digital controllers for more precise and automated firing cycles.
