What is a Kiln Sitter?

Updated July 27, 2026
8:15 am
All About Kilns, How to Use a Kiln

Before the invention of automatic kiln controllers, the kiln sitter was a major innovation in kiln control technology. Introduced in the 1950s, a kiln sitter is a mechanical device that automatically shuts off a manual kiln when it has reached a specified temperature.

Unlike digital controllers, which utilize thermocouples, control algorithms, and microchips to precisely monitor kiln temperature and regulate power, kiln sitters utilize more primitive technology to determine when the kiln has reached temperature: melting and gravity!

Components of a Kiln Sitter

Before explaining the mechanisms of how a kiln sitter determines when to shut off power to the kiln, it’s important to understand the various components of a kiln sitter:

Cone Supports: Two cone supports in the kiln’s are used to support the sitter cone.
Sitter Cone: The sitter cone (or witness cone) is a small pyrometric cone that is placed on top of the cone supports and used to prop up the sensing rod.
Sensing Rod: The sensing rod is a metal rod that connects the interior of the kiln to the exterior components of the kiln sitter. On the interior side of the kiln, the sensing rod is propped up on top of the sitter cone. On the exterior side of the kiln, the sensing rod is connected to a claw assembly that holds up the weighted latching mechanism.
Weighted Latching Mechanism: The weighted latching mechanism on the kiln’s exterior is connected to the sensing rod at the top of the latch. The bottom of the latch is a weighted hinge that will naturally fall unless held in place by the claw assembly.
Timer: A timer on the exterior of the kiln sitter shuts off the kiln when the timer hits its allotted time.
Plunger: The plunger is situated within the weighted latching mechanism. When the latching mechanism is flipped up into the on position, the plunger is depressed so that the timer is initiated.

How a Kiln Sitter Works

In the kiln’s interior, the sensing rod is propped up by the sitter cone. While the sensing rod is propped up, it lowers the claw assembly to hold up the weighted latching mechanism, allowing the kiln to be powered on.

As the kiln heats up, the sitter cone begins to melt at a specified temperature. This allows the sensing rod to move lower under the weight of gravity. As the sensing rod lowers, the assembly claw is lifted.

When the sitter cone melts to a 90° angle, the sensing rod is fully lowered. The assembly claw is fully raised, and the weighted latching mechanism falls, causing the kiln to power off.

Illustration of the position of the sensing rod when the sitter cone is melted. — **When the sitter cone has melted to a 90° angle the sensing rod is fully lowered, and the kiln is powered off.**

How to Use a Kiln Sitter

Using a kiln sitter is extremely easy. Below is a step-by-step guide:

Select a sitter cone that matches the pyrometric cone temperature rating for the ceramic or other material you’re firing. Different materials have different firing temperatures. Select a sitter cone that matches the cone temperature of your material. This ensures that your sitter cone will melt and power off the kiln at the correct temperature.
With one hand, hold up the weighted latching mechanism and attach it to the claw assembly. Make sure that there is proper clearance between the weighted latching mechanism and the claw assembly (usually 1/16th of an inch). The two should not be touching at the start of the kiln firing.
With your other hand, insert the sitter cone between the cone supports and the sensing rod. Make sure the sitter cone is placed evenly on top of the cone supports. It’s also important to center the sitter cone on top of the cone supports (unless you’re intentionally aiming for an abbreviated or a prolonged fire).
Once the sensing rod is situated on top of the sitter cone, set the timer of the kiln 30 to 60 minutes past the projected time it will take your sitter cone to fully melt. This is to ensure redundancy in case there is an error with the kiln sitter.
Power on the kiln and press the plunger to initiate the timer. You’re ready to go! At this point, the kiln sitter should make sure the kiln powers off at the proper time – but the timer switch is there as backup just in case.

Limitations of a Kiln Sitter

When it was first introduced, the kiln sitter was a major advancement in kiln control technology. However, that was over 70 years ago, and there have been major advancements since then. While a kiln sitter is adequate for simple firings, such as those for pottery and ceramics, it is not nearly as precise, versatile, or handsfree as the most advanced digital kiln controllers.

Limitations of kiln sitters include:

Incapable of complex kiln firings with precise ramp rates and multiple setpoints, such as those needed for glasswork.
Leaves room for user error – for instance, improperly positioning the sitter cone can cause the firing to go on for too long or not long enough.
Doesn’t provide extensive diagnostic insight into failed firings.
Requires the kiln operator to constantly check the status of their kiln.

Automatic kiln controllers, on the other hand, perform all the functions of a kiln sitter (and more) but with a greater degree of accuracy, control, insight, and less need for direct oversight or manual intervention.

How Hard Is It to Upgrade Your Kiln Sitter to an Automatic Controller?

The good news is that you can upgrade your kiln sitter-controlled kiln to automatic controls without having to replace your kiln or make significant modifications. Standalone kiln controllers make it easy to upgrade your kiln sitter – check out our step-by-step guide for DIY standalone kiln controller installation!

Choose the Most Advanced, User-Friendly Automatic Kiln Controllers

If you’re tired of the limitations of a kiln sitter, the TAP II and TAP II Pro Controllers by SDS Industries are the most advanced, precise, and easy-to-use automatic kiln controllers on the market today. With responsive touchscreen controls, an intuitive graphical UI, and integration with the TAP Kiln Controller Mobile App, TAP Kiln Controllers can pair with any relay-controlled kiln or oven.

We invite you to explore our selection of automatic kiln controllers, standalones, and conversion kits on our online store. You can also purchase TAP Digital Controllers or TAP-Controlled Kilns and Heat Treat Ovens through one of the following distributors:

Kiln Sitter FAQ

What types of kiln controllers provide an upgrade from a kiln sitter?

Even the most rudimentary programmable digital kiln controller provides a significant upgrade in functionality from a kiln sitter. However, many temperature controller manufacturers provide an extremely frustrating user experience. Don’t worry: You don’t have to trade eye strain, user manuals, and complicated button combinations to enjoy the convenience and precision of an automatic controller. The TAP Ecosystem prioritizes ease-of-use and flexibility without sacrificing precision. We encourage you to compare different types of kiln controllers to find the best controller for your needs.

Where can I find more information about pyrometric cones and ceramic firing schedules?

If you use a kiln sitter, there’s a good chance that you work with ceramics. Looking to learn more about the craft? You came to the right place! Below are different articles and resources we’ve created for potters and ceramic artists:

That’s just scratching the surface! You can find tons of other articles in the TAP IN Blog – or just contact us if there’s any other topics you’d like us to cover.

What are the best options for upgrading a manual kiln?

If you need to upgrade a manual kiln with a kiln sitter, the easiest option would be to purchase a standalone kiln controller. Available in a tabletop or wall mount configuration, standalone kiln controllers provide a quick and easy path to upgrading your kiln to touchscreen controls, unlimited firing schedules, remote temperature monitoring, and more. Check out this article for a step-by-step guide for installing a standalone kiln controller in a matter of minutes!

Scott Shannon

Scott Shannon is President & Founder of SDS Industries. Using his background in electrical engineering and technical program management, Scott helped revolutionize the kiln control industry by pairing simple touchscreen controls with PID algorithms to create the TAP Kiln Controller. Scott graduated in 2010 from the Rochester Institute of Technology with a degree in Electrical Engineering Technology and has over a decade of program management experience with General Dynamics and the US Navy. His favorite part about working at SDS Industries is the chance to solve complex technical issues while supporting and getting to know some of the wonderful people who use TAP.