All About Kilns Archives | SDS Industries

Posted on September 26, 2023September 25, 2023 by Scott Shannon

How Much Do Kilns Cost? The True Costs of Owning a Kiln

For most artists, purchasing a kiln is a pretty big investment. Newer artists, especially, will probably have a lot of questions about what they’re getting into! How much do kilns cost? What about installation and kiln maintenance? Are kilns safe? What type of kiln is right for me? What kind of controller should I use for my kiln?

Don’t worry, we’ve got you covered! You can find our guides on kiln maintenance, kiln safety, types of kilns, and kiln control methods below. And by the end of this article, you’ll have a complete understanding of kiln costs!

Note: For the sake of this article, we’ll be primarily focusing on kiln costs for electric kilns, which are the most common kilns for the hobby kiln and studio kiln market. Gas kilns are typically more expensive, ranging from $3,000 on the extreme low-end to $30,000+ for a high-capacity gas kiln and have their own unique operating and installation costs.

Understanding Kiln Costs

When people think about kiln costs, a lot of the time they only think about the upfront cost of purchasing their kilns. While we’ll be covering purchase costs in depth, there are additional costs to consider. These include installation costs, kiln maintenance costs, material costs, as well as firing costs.

For the hobbyist, understanding these costs will help avoid unforeseen expenses. It will also help determine the most suitable type of kiln and possibly save some money! But for the professional artist, accurately tracking kilns costs can help make sure they’re pricing their wares correctly.

The Cost of Buying a Kiln

For most artists, purchasing a kiln is by far the most expensive part of kiln ownership. Kiln costs vary tremendously, ranging from around $700 for compact kilns to $20,000+ for large, higher powered, industrial grade kilns. There is also a robust used kiln market on Craigslist, eBay, Facebook Marketplace, and other online markets, where pre-owned kilns range from $275 to $3,000+ dollars.

Factors that influence kiln costs include:

Size: Generally speaking, the bigger the kiln, the more expensive – both at the time of purchase and in terms of potential installation, maintenance, and power costs.
Power Rating: Larger kilns and hotter kilns typically require more power and are generally more expensive.
Maximum Temperature: Generally, kilns with a higher maximum temperature are more expensive than comparable kilns with lower maximum temperatures.
Materials Fired: Glass kilns, ceramic kilns, knife kilns, and metal clay kilns (for jewelry) have different price ranges (which we’ll be covering more in-depth below).
Temperature Controller Method: The type of kiln controller that comes included with your kiln will impact its price by up to several hundred dollars – but your controller will have a major impact on your kiln firing experience and the functionality of your kiln.
Shipping Costs: As a larger item, shipping costs for kilns can add a substantial amount to your purchase price. When comparing prices between kiln suppliers, check to see whether shipping costs are included with the purchase of your kiln.

Whew, that may seem like a lot of factors to keep in mind! Don’t worry, we’ll be covering each of these considerations more in-depth. To help narrow your focus when purchasing a new kiln, it’s important to ask yourself the following questions:

How will I be using my kiln? What types of kiln firing schedules will I need to be able to execute?
Based on the media and techniques I use, what kiln firing temperatures and element placement will I need for my projects?
How big does my kiln need to be? How much space do I have to install the kiln at my home or studio?

The more specifically you can answer those types of questions, the easier it will be to determine which features you need to shop for and the kiln costs you should budget for.

Kiln Size Price Ranges

When it comes to buying a kiln, how big does your kiln need to be? Well, that depends…how big are the projects you’ll be firing? If you only need your kiln for slumping glass or firing jewelry or other small objects, chances are you’ll be able to save a lot of money on upfront costs and installation by purchasing a compact kiln.

However, if you’re firing large ceramic pieces – or firing multiple projects at a time – you’ll probably need to spring for a larger kiln.

Below are the average and median prices for kilns based on size (kiln prices throughout this article are based on aggregate price data from Kiln Frog).*

Compact Kilns: Under 15”
- - Price Range: $924.00 – $3318.54
  - Average Price: $1594.83
  - Median Price: $1474.16
Medium Kilns: 13” – 18”
- - Price Range: $916.00 – $4623.86
  - Average Price: $2028.56
  - Median Price: $1921.81
Large Kilns: 17” – 24”
- - Price Range: $1558.00 – $6889.54
  - Average Price: $3240.21
  - Median Price: $3139.00
X-Large Kilns: Over 24”
- - Price Range: $2416.00 – $25328.55
  - Average Price: $6669.63
  - Median Price: $4582.80

As you can see, the size of the kiln makes a big difference in price!

*Price data in this article includes current promotions – prices may vary.

Kiln Costs Based on Power Rating

Another factor that can influence kiln costs – for purchase, installation, and your electric bill – is the power rating of your kiln. When it comes to power rating, there are three ratings you need to understand: voltage, amperage, and wattage.

Voltage is the electric potential of a circuit. Comparing electricity to plumbing, voltage could be considered the pressure in a pipe. In the U.S., kilns typically come in two different voltage configurations: 120V and 240V, which correspond with the electric grid. 120V kilns are typically less expensive and match the voltage of a standard residential wall outlet; however, kilns exceeding 15 amps will need to be installed on a dedicated circuit.

A 240V kiln, on the other hand, needs a special wall outlet (other large appliances, such as wall ovens, AC units, and dryers use 240V outlets). Chances are, you will need the help of an electrician to run a new outlet in order to install your kiln. According to HomeGuide, this will cost anywhere from $250 – $800.

Amperage is the units of electrical current in a circuit. Extending the plumbing analogy, current is similar to the capacity of a pipe: the wider the pipe, the more water that flows. Kilns range from 13 amps to 80 amps. 120V kilns typically only go up to 30 amps, while 240V kilns can range anywhere from 30 amps to 80. At 48 amps or higher, a kiln will have to be wired directly into your power supply – another additional expense!

Watts measure the rate of power flow, calculated by multiplying voltage by amperage. Smaller 120V kilns typically draw between 1500 and 1800 watts, while a large 240V kiln can draw up to 11000 watts. TAP Kiln Controllers by SDS Industries allow you to enter your kiln’s watt rating, as well as the cost per kilowatt hour from your electric bill to automatically calculate your cost per firing.

The kiln costs tracking feature on TAP Kiln Controllers allows artists to automatically track how much they spend per fire. — **The TAP Kiln Controller by SDS Industries allows artists to easily track their cost per fire on their electric kiln.**

Kiln Costs by Maximum Temperature

Different kilns are capable of reaching different maximum temperatures. Generally, the hotter the kiln, the higher the kiln costs! If you need to fire Cone 14 porcelain, expect to spend more money than if you only need to fire Cone 06 ceramics. Reviewing these firing schedules for glass, ceramic, and metal heat treat can help you figure out which temperatures you’ll need your kiln to be able to reach based on the media and techniques you use.

Kiln Costs by Materials Fired

Speaking of media, when shopping for a new kiln, you’ll find that there are different kilns designed specifically for glass, ceramics, metal heat treat (for objects such as blades and knives), and metal clay (for jewelry and small metal trinkets). How do the materials you fire impact kiln costs?

Kilns have different dimensions and maximum temperatures based on the materials they’re designed to fire. Generally, metal clay kilns will be smaller than glass kilns, which will be smaller than knife kilns. Ceramic kilns tend to be larger and cylindrical, since you can stack pottery during fire. You can expect the price of the kiln to scale accordingly.

Additionally, ceramic kilns and heat treat kilns will typically need to be capable of reaching higher temperatures than metal clay kilns or glass kilns.

Broadly speaking, metal clay kilns will be the least expensive, and ceramic kilns will be the most expensive. Glass kilns and metal heat treat ovens often fall somewhere in between.

Temperature Controller Costs

Finally, an extremely important consideration when buying a kiln is deciding which brand and model of kiln controller to purchase with your kiln. After all, the kiln controller will be your primary interface with your kiln and will largely determine your user experience. Your kiln control method will determine the accuracy of your kiln firing, as well as what you can program the kiln to do.

Upgrading to a fully featured touchscreen programmable digital kiln controller will add a few hundred dollars to your kiln costs compared to a rudimentary 3-key model. Is it worth it?

In our opinion, yes. Definitively. An advanced, easy-to-use kiln controller like the TAP Kiln Controller gives you the ability to:

Easily navigate your controller and manage your firing schedules with just a few finger presses.
Name, save, and edit unlimited firing schedules with an unlimited number of steps per schedule.
Easily find and select the right schedule with alpha-numeric, full text displays.
Integrate your controller with the TAP Kiln Control Mobile App so that you can remotely monitor your kiln and create, modify, and execute firing schedules from your mobile device.
Enjoy peace-of-mind with push notification alerts and alarms to keep you informed of your firing status, notify you when it’s time for preventative maintenance, or let you know when unexpected conditions occur.

Additionally, SDS Industries is working on a lineup of more cost-accessible controller options that contain many of the advanced functions of TAP at a lower price point, with all kiln controller inputs performed via your smartphone.

Read our side-by-side kiln controller manufacturer comparison to compare the features of TAP against what you get with lower-priced controller options.

Additional Kiln Costs

In addition to kiln costs at point of purchase and installation, there are also longer-term costs to keep in mind.

We mentioned installation costs earlier. You should plan on budgeting up to $800 if you will need the help of an electrician in installing your kiln. Additionally, if you’re purchasing a ceramic kiln, you may need to buy and install a ventilation system which can run another $200 to upwards of $800.

For kiln maintenance, you will have to replace thermocouples, elements, and mechanical relays at regular intervals. Depending on how frequently you use your kiln and the temperatures you fire to, you should plan on budgeting at least $100 to $200 dollars every year or two to replace these components.

And, finally, you will have to budget for materials. Material costs can vary greatly per artist, but you should plan accordingly!

Conclusion

There you have it! Hopefully, this article has given you a full understanding of the true cost of owning a kiln. However, you should look at kiln costs as a long-term investment. If you take care of your kiln, it could last you for decades and give you countless hours of enjoyment and self-expression – so it’s hard to put a price tag on that! But it’s also important to know what you’re getting into and budget accordingly.

Explore Programmable Digital Kiln Controllers by SDS Industries

If you’re buying a new kiln, you’ll want to make sure it’s coming with the right controller. Ask your kiln supplier about TAP! The TAP and TAP II Controllers by SDS Industries provide users the most advanced, precise, and easy-to-use programmable digital kiln controllers on the market today. With responsive touchscreen controls, an intuitive graphical UI, and integration with the TAP Kiln Control Mobile App, TAP Kiln Controllers can pair with any relay-controlled kiln or oven.

We invite you to explore our selection of programmable 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:

Posted on September 19, 2023September 19, 2023 by Brittany Gabel

Kiln Maintenance & How to Care for Your TAP Controller

Owning a kiln is a little bit like owning a car. With mindful operation and a little bit of routine maintenance, your kiln should last for decades! Proper kiln maintenance ensures your kiln remains safe and operational during that time.

The good news is that kiln maintenance is much simpler (and less expensive!) than maintaining your car. While a car has a gazillion different parts that will eventually need to be replaced, kilns have far fewer points of potential failure. And while it can be a good idea to occasionally enlist the help of an electrician or a kiln engineer (especially during installation), most kiln operators will be able to perform regular kiln maintenance by themselves!

Better yet, today’s programmable digital kiln controllers like TAP Controllers by SDS Industries include advanced diagnostics features and preventative maintenance alerts, so that you know when it’s time to replace kiln elements, thermocouples, and relays. That way, you’re able to maintain optimal performance without having to worry about your kiln conking out on you mid-project!

Routine Maintenance: Component Replacement

Just like with cars, there are certain kiln components that will wear down over time and will need to be replaced on a regular basis, so we’ll start with those first. These components include:

Thermocouples: Thermocouples – the probe that measures the temperature of your kiln – are regularly subjected to high temperatures. Over time, thermocouples become corroded and start crumbling at the tip and will no longer be able to accurately record temperature. You’ll need to replace your thermocouples on a regular basis – typically every 30 to 50 firings for Type K thermocouples.
Kiln Elements: Elements are the metal coils that line the inside of your kiln and heat up when they receive electric current. Over time, kiln elements become corroded and their resistance increases – meaning that they begin to become less efficient and require more electric current to heat your kiln. The lifespan of kiln elements can range anywhere from 1 to 5 years. Their lifespan depends largely on the type of kiln you’re using, the temperatures you regularly fire to, as well as firing frequency and duration.
Mechanical Kiln Relays: Kiln relays regulate the power to the elements of your kiln, allowing them to heat up or cool down. Mechanical relays, which come standard on most kilns, are subject to failure after around 200,000 cycles and will need to be replaced every 12-24 months. Alternatively, investing in mercury or solid-state relays can reduce kiln maintenance costs, since those relays last much, much longer. Mercury relays last around 5 million cycles and will only need to be replaced every 15-20 years. Finally, solid-state relays don’t have any moving parts and can last over 1000 years (TAP Kiln Controllers are compatible with all three relay types!).

Replacing these components is an inevitable part of kiln maintenance. TAP Kiln Controllers calculate health and life expectancy for each of these components based on user defined thresholds, letting you know when it’s time to replace each component to maintain optimal kiln performance.

Other kiln components that may require replacement include kiln bricks, kiln lids, electrical wires, and kiln controllers. However, there are steps you can take to monitor and prolong the lifespan for all of these components:

For kiln bricks, be careful when moving your kiln or when placing or removing objects from your kiln. Regularly visually inspect the interior of your kiln. Kiln bricks will need to be replaced when they’re no longer able to properly support kiln elements or when significant chunks of kiln bricks are missing affecting the thermal efficiency of your kiln.
For kiln lids, be mindful when opening and closing your kiln to prevent denting or damaging the lid. Do not lean on your kiln or use it as a shelf for storing objects.
Regularly inspect electrical wires for discoloration, brittleness, or corrosion. Immediately replace these components if necessary.
For kiln controllers, make sure they are properly installed and regularly keep the screen clean and free of debris. We’ll be going more in-depth on how to care for your TAP Controller further below!

TAP Kiln Controllers give users a detailed error log that helps them identify component failure. For a breakdown of error messages and troubleshooting steps, check out p. 12 of the TAP II Controller User Manual.

Kiln Maintenance: Installation

Ben Franklin once said, “An ounce of prevention is worth a pound of cure.” This is definitely true when it comes to kiln maintenance. Proper installation will prevent a ton of potential problems later down the road. Below are a few principles for kiln installation that will prolong the life of your kiln:

Select a space with adequate clearance and proper surfaces. Heat is a common cause of kiln component failure (or worse!). When installing your kiln, make sure your kiln has at at least 18” of clearance from non-combustible surfaces and 36” from combustible surfaces. Make sure the kiln is installed on a level surface that’s non-combustible and able to withstand high temperatures.
Install your kiln in a dry area. Water and electricity don’t mix! Installing your kiln in a dry area prevents shorts and surges and protects your kiln from corrosion, which will significantly reduce the life of your at home kiln components.
Follow manufacturer guidelines for installation. When you purchase your kiln, you should receive manufacturer guidelines for installation and kiln safety. Make sure to adhere to these closely when installing your kiln. If you purchase a used kiln, contact the manufacturer for installation guidelines.
Get any electric work done by a qualified electrician. At home kilns, especially larger ones, utilize a lot of electricity, so it’s important to make sure that you use a dedicated circuit with a properly rated power outlet and never use an extension cord. Enlisting the help of a certified electrician during installation helps reduce the likelihood of kiln maintenance problems down the road.
Make sure thermocouples are properly installed. Thermocouples help your automatic kiln controller precisely regulate the temperature of your kiln. However, thermocouples will only give you accurate temperature readings if they’re properly installed! Thermocouples should be inserted an inch or two into the interior or your kiln and should have at least 1″ clearance from any shelves, components, or any materials you place inside your kiln.
For DIY kiln builds, make sure relays are properly installed. Kiln relays ensure the safety of your kiln by cutting power to the elements if the kiln gets too hot. For DIY kiln or oven builds, it’s important to choose the right type of relay; for instance, solid-state and mercury relays will have far more longevity and reliability than mechanical relays. But it’s even more important to make sure that relays are properly rated and installed and that you utilize a safety relay to add redundancy in case one relay fails.
Don’t store your kiln outside. Since indoor kiln installation for ceramics and glazing requires proper ventilation, it might be tempting to keep your kiln outside. We strongly, strongly advise against that. Exposure to the elements will reduce the lifespan of your kiln and all of its components.

Kiln Maintenance Tips Before, During, and After Firing

While proper installation and regularly replacing necessary components can prevent a host of kiln maintenance issues down the line, there are also steps you can take before, during, and after firing to prolong the life of your kiln. Below is a list of tips for kiln care and maintenance!

Regularly clean your kiln. Debris, dust, and glazes in the interior of your kiln can reduce element efficiency, ultimately reducing their lifespan. Carefully dusting around the element grooves and regularly vacuuming your kiln’s interior helps prevent this. Just be careful not to damage the elements or the surrounding brick! If melted glaze gets on your kiln brick, make sure to gently scrape it off to avoid it absorbing into the kiln brick. You can also use kiln wash to minimize potential damage from dripping glaze (just make sure not to get it on the kiln’s elements!). Additionally, you should only clean your kiln when it is powered off to avoid causing electrostatic discharge if you accidentally hit the thermocouple and other mishaps.
Keep your lid closed between firings. Leaving your kiln’s lid open leaves it susceptible to dust, debris, or wildlife getting in (yikes!). Make sure to keep your lid closed when you’re not using the kiln.
Do not lean on your kiln. Leaning on your kiln can cause dents or stress fractures, reducing its efficiency.
Don’t use your kiln for storage. Storing items in your kiln can easily damage the bricks or elements of your kiln.
Be careful opening and closing your kiln. Be gentle opening and closing the lid of your kiln to avoid damaging the lid or the top-edge of your kiln.
Don’t open the kiln for prolonged periods when it’s still hot. While it may be necessary to occasionally open your kiln to monitor the status of your work during firing, prolonged exposure to abrupt changes in temperature can cause cracks and fractures in your kiln brick.
Regularly inspect kiln elements. Regularly visually inspect your kiln’s elements for debris buildup or corrosion. Occasionally, kiln elements may become dislodged from the grooves in the brickwork and may need to be repositioned. Additionally, you can use a multimeter to test their resistance. Once they exceed 10% of the recommended resistance in your kiln’s user manual, it’s time for them to be replaced.
Invest in a safety relay controller. The biggest threat to your kiln’s lifespan (as well as your safety and the welfare of your household and personal property) is too much temperature. Occasionally relays fail. If they fail in the open position, your kiln will keep heating up indefinitely. This is no bueno! Investing in a redundant safety relay controller like the TAP Monitor ensures that your kiln safely shuts off in case of relay failure.

Caring for Your TAP Controller

TAP Kiln Controllers are carefully manufactured from high-quality components and backed by an industry leading 3-year warranty. However, like any advanced electronic device, they are subject to failure, wear and tear, and their lifespan can be prolonged by proper care. Below are tips for caring for your TAP Controller:

Make sure your controller is properly installed. You can find tips for kiln controller installation for DIY builds here, but if you have any questions we encourage you to contact us.
Regularly clean your screen to keep it free from any dust or debris.
Avoid wearing jewelry or watch while using your TAP Controller, as these can result in scratches on the screen.
Again, we cannot stress this enough, do not store your kiln or your controller outdoors.
Regularly review diagnostic errors so that you can spot and troubleshoot potential errors with controller output.
Make sure your controller is updated to the latest software. If you’re connected to WiFi, updates will be downloaded automatically and you will be notified via pop-up. Simply follow the on-screen instructions. But you can find instructions for manually updating kiln controller software for your TAP Controller here.

Additionally, SDS Industries is always working to improve our kiln controllers and provide users with new features that improve their kiln firing experience. We’re currently working on an automated device monitoring software for TAP Controllers that monitors device performance and health. By monitoring various controller metrics, the software will be able to detect potential controller degradation so that we can be proactive and inform you if your controller needs repairs.

Tips for Cleaning Your TAP Controller

TAP Kiln Controllers use a resistive touchscreen for user inputs. As mentioned earlier, to maintain optimal performance, you should regularly clean your TAP Controller to ensure it’s free of dust, debris, smudges, and fingerprints. Below are a couple dos and don’ts for cleaning your TAP Controller:

Before cleaning the display, use a dry, lint-free microfiber cloth to gently wipe away any dust from the touchscreen.
Use distilled water to dampen the microfiber cloth to gently clean the touchscreen display.
Do not use the following cleaning agents: tap water, ammonia, acetone, ethyl alcohol, methyl chloride, or ethyl acid, as these can cause damage to your screen.

Explore Programmable Digital Kiln Controllers by SDS Industries

The TAP and TAP II Controllers by SDS Industries provide users the most advanced, precise, and easy-to-use programmable digital kiln controllers on the market today. With responsive touchscreen controls, an intuitive graphical UI, and integration with the TAP Kiln Control Mobile App, TAP Kiln Controllers can pair with any relay-controlled kiln or oven.

Posted on August 29, 2023August 28, 2023 by Brittany Gabel

How to Use a Programmable Digital Kiln Controller

Similar to other industries, the mid-1980s brought major advancements to kiln control technology. Manual kilns and kiln sitters gave way to programmable digital kiln controllers. Kiln operators no longer had to manually adjust their kilns for each segment of their kiln firing schedule. Instead, they could use programmable kiln controllers to input their entire firing program in advance, and the controller would carry out the program automatically!

Also known as electronic or automatic kiln controllers, programmable digital kiln controllers are computerized controllers that automatically cycle the relays to a kiln’s heating elements on and off in accordance to predefined ramp rates, setpoints and hold times.

Compared to manual controllers, programmable kiln controllers significantly streamline the firing process, reducing the possibility of user error and ensuring consistently repeatable firing conditions.

Programmable Digital Kiln Controller Input Methods

When it comes to programmable digital kiln controllers, there are two primary input methods: keys and touchscreen.

Key-Based Controls

Early programmable kiln controllers all used keys, or analog buttons, in order to program the controller. Many kiln controllers today still use this input method. Common configurations are 3-key controllers and 12-key controllers, but some kiln controllers use as many as 24 keys!

However, regardless of how many keys a controller has, this control method presents several inconveniences:

Keys must be pressed multiple times to increase setpoints, cycle through preprogrammed schedules, or control other inputs.
Key-based controllers often have small, hard-to-read screens that make it impossible to see all the relevant information about a firing schedule.
These controllers have multi-layered menus that can be extremely difficult to navigate.

Good luck using these controllers without constantly having to consult the user manual and press a LOT of buttons!

Touchscreen Controls

In 2015, SDS Industries revolutionized the kiln control industry, by replacing keys and alarm-clock-like screens with intuitive, responsive touchscreen controls and an easy-to-read graphical UI. The TAP Controller, and later the TAP II Controller, allows kiln operators to quickly and easily program their kiln with just a few presses of their finger on the controller or their via their smartphone with the TAP Kiln Control Mobile App.

When it comes to programmable digital controllers, touchscreen controls present several major advantages:

Intuitive, user-friendly menus that are designed for complete navigation with minimal finger presses.
Alpha-numeric, full text displays of kiln firing schedules to make it easy for operators to access, edit, and execute the right firing schedule.
The ability to create a theoretically unlimited number of kiln firing schedules, each containing a theoretically unlimited number of steps, so users don’t have to relegate schedules to their firing notebook when they run out of storage.
Integration with the TAP Kiln Control Mobile App to allow users to create, modify, and execute kiln firing schedules from their mobile device when their kiln controller is connected to Wi-Fi.

Additionally, TAP Digital Kiln Controllers include PID-driven precision, advanced diagnostics, complete firing logs, and preventative maintenance alerts, and more, to ensure that the controller and kiln maintain optimum performance.

Types of Kilns that Use Programmable Kiln Controllers

Today, programmable digital kilns controllers are the standard for industrial kilns and have become increasingly common for hobby and studio kilns. Many programmable kiln controllers include preset firing schedules for glasswork, ceramics, glazes, and heat treat, greatly reducing the learning curve for new artists while still offering veteran artists the ability to completely customize their firing schedules.

Retrofitting Your Kiln with a Programmable Controller

Whether your kiln came equipped with a manual controller or you’re using an outdated programmable controller, retrofitting your kiln with a modern programmable digital kiln controller is easy through the use of standalone controllers or conversion kits. Standalone controllers are a plug-and-play solution for upgrading your manual kiln to automatic controls, while conversion kits enable you to upgrade an existing automatic controller with no (or minimal) modification to your kiln.

Check out our step-by-step guide for installing programmable digital kiln controller standalones and conversion kits!

How to Use a Programmable Digital Kiln Controller

The specifics of how to program your kiln using a digital kiln controller largely depends on the type of controller you’re using. However, generally, upon powering on your kiln you will use the input method on the controller to either select a saved or preset schedule or create your own (you can do this before or after loading your wares). If you’re new to kiln firing, make sure to familiarize yourself with kiln safety guidelines prior to executing your firing schedule.

Once you have selected your firing schedule, press ‘Start’ and your programmable digital controller will automatically execute your firing schedule to completion. Easy as that! While it may be tempting to trust everything to your programmable kiln controller, for safety reasons you should never leave your kiln unattended during firing. While programmable controllers are extremely reliable compared to relying on a kiln sitter, there is always the possibility of relay failure or other technical mishaps (for additional safety, we recommend using an additional limit controller as an added layer of relay redundancy to force safety shutoff if the kiln exceeds certain temperature thresholds).

Programming a TAP II Digital Kiln Controller

While we can’t provide a How-To for using every programmable kiln controller on the market, below we’ll be looking at how to program a TAP II Kiln Controller (the UI for the original TAP Controller is extremely similar):

Step 1: Starting from the ‘Home Screen’

Below is a picture of the home screen on a TAP II Kiln Controller:

To access kiln firing schedules, or create a new one, press ‘Start’ on the right side of the screen.

Step 2: Using the ‘Schedule Selector’ Screen

On the ‘Schedule Selector’ screen, you have the ability to access all of your saved or preset kiln firing schedules by scrolling through the menu on the left side of the screen. To execute an existing schedule, select the schedule from this screen, then press ‘Start’!

If you need to edit a schedule, clicking the ‘Edit Icon’ beside the schedule title allows you to edit that firing schedule. Or, to create a new schedule, click ‘New’ on the right side of the screen.

Step 3: Edit and Add Steps to Your Firing Schedule

Clicking the ‘Edit Icon’ will bring you to the ‘Edit Schedule’ screen:

On this screen, you have the ability to add new steps and edit the Schedule Name, Ramp Rate, Setpoint, and Hold Time for each step. Additionally, you have the ability to set alerts to notify you when your kiln has reached its setpoint or hold time for each specific step. When you’re finished editing your firing schedule, click ‘Save.’

Step 4: Execute Your New Firing Schedule

When you click ‘Save,’ the controller will bring you back to the ‘Schedule Selector’ screen. Select your desired schedule and then press ‘Start.’

From there, your TAP II Controller will automatically execute your new firing schedule. From the ‘Execute’ screen, you’ll be able to monitor exactly where your kiln is in terms of your firing schedule, as well as skip steps, access firing logs, or abort your firing.

Please Note – Most programmable digital kiln controllers are not nearly that easy-to-use or intuitive. A huge part of our focus at SDS Industries is to make using a programmable kiln controller as simple, precise, and straightforward as possible!

Explore Programmable Kiln Controllers by SDS Industries

The TAP and TAP II Controllers by SDS Industries are the most advanced, precise, and easy-to-use programmable digital kiln controllers on the market today. With responsive touchscreen controls, an intuitive graphical UI, and integration with the TAP Kiln Control Mobile App, TAP Kiln Controllers can pair with any relay-controlled kiln or oven.

Posted on August 22, 2023August 21, 2023 by Scott Shannon

ICS Controllers for Industrial Control Systems

Beyond industrial kilns, ovens, and furnaces, electric temperature controllers are used in a wide variety of industrial processes and applications. Commonly referred to as ICS controllers, electric temperature controllers are used to monitor and regulate temperatures in manufacturing or storage processes where consistent outcomes rely on precise temperature control.

Unfamiliar with the acronym? Don’t worry! Below, we’ll be exploring industrial control systems (ICS) and the role and applications of ICS controllers.

What is an Industrial Control System?

Industrial control systems (ICS) refer to the equipment and software that are used to monitor, regulate, and control the behavior of machinery in automated industrial processes. An industrial control system provides physical or digital means through which humans can interface with machinery, providing inputs (or setpoints) to tell the machinery when and how to act.

Industrial processes that utilize industrial control systems include:

Manufacturing
Factory Automation
Chemical Processing and Storage
Heat and Cooling Systems
Oil and Gas Processing
Water and Sewage Treatment
Telecommunications
Food Processing
Healthcare and Pharmaceuticals

Important ICS-Related Terminology

Before exploring the role of ICS controllers, there are a few terms that are important to understand:

Localized Control System: In localized control systems, inputs are directly entered into each individual machine via a machine-mounted control panel. In a localized control system, machinery doesn’t communicate with each other, and there is no overall view or centralized process control.
Centralized Control System: More sophisticated industrial control systems use sensors and electronic signals to consolidate control of all machines to a centralized control room.
Distributed Control System (DSC): Distributed control systems are computerized control systems that use a series of sensors and automatic controllers distributed throughout a factory. In a DSC, controllers automatically regulate the behavior of individual machines but are also connected to a centralized network so that an operator can monitor and adjust the overall process. DSCs are more efficient, consistent, and cost effective than localized or centralized control systems.
Process Variables (PVs): Process variables are the actual measured values of a particular part of an industrial process that is being controlled or measured. So, for example, when it comes to temperature control the process variable would be the current temperature of an industrial kiln or oven, as opposed to the desired temperature (or setpoint).
Setpoints (SPs): A setpoint is the desired or target value for a process variable. In terms of temperature control, the setpoint would be the desired temperature of a kiln or oven according to its firing schedule.
Final Control Elements (FCEs): Final control elements are the mechanical devices that physically change a process in response to setpoints within an industrial control system. These include elements, valves, and dampers.
Control Loops: A control loop consists of the process sensor, controller, and final control elements – basically all of the components needed to adjust process variables to match desired setpoints.
Human Machine Interface (HMI): A human machine interface is the user interface or dashboard from where an operator can control a machine, system, or device.
Discrete Controllers: Discrete controllers consist of a single control loop to directly view and interface with a single machine.
Programmable Logic Controllers (PLCs): Programmable logic controllers are digital controllers that receive data through inputs (such as thermocouples) and uses the internal logic that’s been programmed into it to adjust outputs to matched desired setpoints. TAP Kiln Controllers are examples of programmable logic controllers.
SCADA Systems: SCADA stands for Supervisory Control and Data Acquisition. SCADA systems consist of all hardware and software that are used to control, monitor, and gather data from industrial devices and processes – both remotely and on-site.

Understanding the Role of ICS Controllers

An ICS controller is a device where operators can input setpoints for an industrial control system. The ICS controller receives data from input sensors and adjusts outputs to the final control elements in order for the industrial control system to reach its desired setpoints.

ICS controllers play an important role in ensuring that industrial processes are executed effectively and consistently.

The TAP ICS Controller is an advanced controller for industrial control systems that rely on precise temperature inputs and outputs. — **The TAP Controller by SDS Industries includes an advanced feature set for use in industrial control systems.**

ICS Controllers for Temperature Control

While there are different types of ICS controllers for managing different process variables throughout an ICS, for the sake of this article we’ll be focusing on ICS controllers for temperature control. Many industrial systems rely on heating, cooling, or maintaining precise temperatures to alter or preserve the physical properties of material.

Industrial kilns, ovens, furnaces, and temperature-controlled drums, freezers, and storage units all rely on ICS kiln controllers to regulate temperature.

ICS controllers can be manual or automatic. Manual ICS controllers rely on constant user input through analog dials and switches to regulate power to final control elements. Automatic ICS controllers, on the other hand, are programmed to reach various setpoints over specific time periods and automatically adjust the final control elements to achieve the desired temperature.

Benefits and Features of TAP ICS Controllers

SDS Industries’ TAP Digital Controllers include a variety of features that make them ideal for industrial control systems, including:

PID (Proportional Integral Derivative) control algorithms to ensure maximum accuracy between temperature input and output.
The ability to create, store, edit and automatically execute an infinite number of firing profiles with an infinite number of steps.
The ability to remotely monitor commercial kilns and edit and execute firing processes through the TAP Kiln Control Mobile App.
Advanced diagnostics and preventative maintenance alerts to ensure peak performance for industrial thermal processes.
High quality components for maximum precision and durability.
Wi-Fi capability to seamlessly integrate TAP Controllers to a distributed control system.

The TAP Kiln Control Mobile App allows operators to remotely monitor and make adjustments to temperature control elements in industrial control systems. — **The TAP Kiln Control Mobile App allows operators to remotely monitor and make adjustments to temperature control elements.**

Explore ICS Controllers by SDS Industries

The TAP and TAP II Controllers by SDS Industries are the most advanced, precise, and easy-to-use ICS controllers on the market today. With responsive touchscreen controls, an intuitive graphical UI, and integration with the TAP Kiln Control Mobile App, TAP Kiln Controllers can pair with any relay-controlled industrial kiln, oven, or furnace to allow you to easily manage control system setpoints.

We invite you to explore our selection of programmable ICS 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:

Posted on August 15, 2023August 21, 2023 by Scott Shannon

What is an Industrial Kiln? Understanding Commercial Kilns, Furnaces, and Ovens

Kilns aren’t just limited to home and studio applications. Industrial kilns, or commercial kilns, are used in a wide variety of industrial processes. From mass producing ceramic tableware to processing plastic, industrial kilns are used to create many of the objects you use in day-to-day life.

Compared to kilns for personal or artistic use, industrial kilns are typically much larger and more powerful, designed to process large quantities of materials in industrial settings. Designed for mass production and commercial use, industrial kilns are often permanently installed and capable of reaching extremely high temperatures.

Industries That Use Commercial Kilns

Industrial kilns, furnaces, and ovens are used across a wide variety of industrial sectors including:

Ceramic: Industrial kilns are used in the ceramic industry to produce tableware, pottery, tile, and other ceramic products.
Glass: Industrial glass kilns, furnaces, and annealers are used in the glass industry to produce windows, sheet glass, drinkware, bottles, mirrors, and more.
Construction and Building Materials Manufacturing: In the construction industry, commercial kilns and heat treat ovens are used to produce brick, tiles, windows, machinery, tools, and other building materials.
Metal Processing and Manufacturing: Industrial heat treat ovens and furnaces are used to process metal for a wide variety of applications including, but not limited to, knifemaking, jewelry production, and silverware manufacturing.
Plastic Processing and Manufacturing: The plastic processing and manufacturing industry uses commercial kilns to heat raw material into finished or semi-finished plastic products.
Food Industry: In the food industry, industrial kilns and commercial ovens are used to dry, cook, and process food.
Waste Management: The waste management industry uses commercial furnaces for incineration, recycling, and energy recovery.

However, these are just a few of the industries that use industrial kilns, furnaces, and ovens. Kilns and ovens are also used in the medical, pharmaceutical, electronic, automotive, military and defense, and aerospace industries (among countless others!).

Read more about the history of industrial kilns.

The Differences Between Industrial Kilns, Furnaces, and Ovens

When it comes to commercial thermal processing equipment, there are three main categories: kilns, furnaces, and ovens. Superficially, all these terms can be used interchangeably. However, typically, each of these terms is used to denote equipment used for specific use-cases or to describe equipment capable of reaching specific temperatures:

Industrial Kiln: More likely to be used to describe thermal processing units used to process ceramics or glass. Typically used to describe units that reach maximum temperatures of approximately 1400° C (2552° F).
Industrial Furnace: More likely to be used to describe thermal processing units used for metal heat treatment and metallurgy. Often used to describe units that reach peak temperatures exceeding 1400° C (2552° F), all the way up to 1750° C (3182° F).
Industrial Oven: More likely to be used to describe thermal processing units used for the food, electronic, medical, and pharmaceutical sectors. Often used to describe units whose processes don’t result in a fundamental phase change (such as drying, moisture reduction, and bakeout).

Industrial Kiln Controllers

Commercial kilns are “industrial grade,” which means they have more stringent requirements for kiln safety and input and output precision. Industrial kiln controllers, also known as ICS (Industrial Control Systems) kiln controllers, must be capable of executing a variety of complex firing schedules with extreme precision.

The TAP Kiln Controller by SDS Industries includes a variety of features and benefits for industrial kiln usage, such as:

PID (Proportional Integral Derivative) control algorithms to ensure maximum accuracy between temperature input and output.
Multizone temperature control to set specific temperatures in up to three different areas of an industrial kiln or oven.
The ability to create, store, edit and execute an infinite number of firing profiles.
The ability to remotely monitor commercial kilns and edit and execute firing processes through the TAP Kiln Control Mobile App.
Advanced diagnostics and preventative maintenance alerts to ensure peak performance for industrial thermal processes.
High quality components for maximum precision and durability.

Read more about the roles and functions of industrial kiln controllers.

Explore Industrial Kiln Controllers by SDS Industries

The TAP and TAP II Controllers by SDS Industries are the most advanced, precise, and easy-to-use industrial kiln controllers on the market today. With responsive touchscreen controls, an intuitive graphical UI, and integration with the TAP Kiln Control Mobile App, TAP Kiln Controllers can pair with any relay-controlled kiln or oven to allow you to easily manage and execute your kiln firing schedules.

We invite you to explore our selection of programmable industrial 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:

CTA: Choose the Most Advanced Industrial Kiln Controllers

Posted on August 8, 2023September 6, 2023 by Scott Shannon

Thermocouples: Differences Between Thermocouple Types

In order to successfully execute a kiln firing schedule, it’s imperative that your kiln controller is receiving accurate temperature readings from your kiln. This is where thermocouples come into play.

Thermocouples measure temperature and send that information to the kiln controller which then automatically adjusts the power of the kiln according to its preprogrammed firing schedule.

What is a Thermocouple

A thermocouple is a self-powered temperature monitoring device that converts thermal energy into electric current in order to accurately measure the temperature of a heat source. Simple, inexpensive, reliable, durable, and capable of measuring a wide range of temperatures, thermocouples are used in a wide variety of applications. From monitoring the temperature of kilns and ovens, to residential thermostats, automotive and aircraft sensors, industrial and scientific processes, and more, thermocouples are used everywhere.

How Do Thermocouples Work?

Thermocouples consist of two different types of metal (or alloy) wires that run parallel to each other and join together at the tip. When the tip of the thermocouple (also known as the thermocouple measuring junction or the hot junction) is exposed to temperature, the two wires heat up or cool down to different temperatures, generating electromotive force. This phenomenon is known as the Seebeck Effect.

The two metal wires also connect at the reference junction (or the cold junction), which is kept at a constant, known temperature. Historically, this known temperature was created by using an ice bath for a 32° Fahrenheit reference, but today this is accomplished with electronic sensors which allow for thermocouples to be used over a range of ambient temperatures.

The voltage created corresponds with the relative temperature difference between the two junctions, allowing a sensor to calculate the temperature at the measuring junction with an accuracy of within 1° or 2° C.

Factors That Affect Accuracy

While thermocouples are reliable and widely used, there are several factors that can impact the accuracy of their readings at any given point in time:

Size: The physical dimensions of a thermocouple can affect its response time and, therefore, instantaneous accuracy. Smaller thermocouples may exhibit faster response times due to their reduced mass, but they may also be more susceptible to measurement errors caused by thermal gradients or conduction losses.
Location: The placement of a thermocouple within a kiln or oven can influence the accuracy of its readings. Factors such as proximity to heat sources, shielding from external influences, and the ability to measure representative cold junction temperatures can all impact the reliability of the measurements.
Tolerance: Thermocouples have specific tolerances, which define the maximum allowable deviation from their specified temperature-to-voltage relationship. If a thermocouple exceeds its tolerance limits, the readings may become less accurate or unreliable. It is essential to select a thermocouple with an appropriate tolerance for the desired temperature range and application.
Self-heating: The heating of a thermocouple itself can introduce errors in the temperature measurements. Self-heating occurs when the current flowing through the thermocouple generates heat, which can lead to a temperature increase at the sensing junction. This self-heating effect can result in an offset or error in the measured temperature, particularly in low-temperature applications or when high currents are used.
Kiln or Oven State: When a kiln’s elements are on, the air near the elements becomes hotter than the rest of the air inside the kiln. This temperature gradient produces convection currents which swirl warmer and colder air around inside the kiln. As this air moves and passes over the thermocouple, it can cause swings in the temperature reading depending on the response time of the thermocouple. These convection currents are less problematic when the kiln’s elements are off and the internal air temperature becomes more homogenized.
Additional Factors: Other factors that can impact thermocouple readings include electromagnetic interference (commonly produced by switching mechanical relays), oxidation or contamination of the thermocouple junctions, mechanical stress or strain on the thermocouple wires, and the type of reference junction used for cold junction compensation.

To ensure accurate temperature measurements, it is crucial to consider these factors and choose the appropriate thermocouple type, size, location, and tolerance based on the specific application requirements, as well as the type of controller you’re using. Regular calibration and maintenance of the thermocouples are also recommended to verify their accuracy and detect any drift or degradation over time. Some temperature controllers, such as TAP Kiln Controllers by SDS Industries provide diagnostics and preventative maintenance alerts based on usage to ensure thermocouple accuracy.

What are the Different Types of Thermocouples?

There are a wide variety of thermocouple types that are suitable for different types of applications. Each type of type of thermocouple has different characteristics for temperature range, sensitivity, durability, vibration resistance, chemical resistance, and application capability depending on the physical properties of its metals.

Thermocouple types are named according to a lettering system. Thermocouple Types C, E, J, N, K, and T are composed of base metals and Types B, R, S, and P are composed of noble metals. Below we’ll be exploring the characteristics and applications of the different thermocouple types.

Base Metal Thermocouples

Base metal thermocouples are the most common types of thermocouple. These thermocouples are composed of base metals or alloys, such as iron, copper, nickel, and chromel.

Type C Thermocouples

Material: Tungsten-Rhenium (+ and -)
Temperature Range: 32 – 4208° F (0 -2320° C)
Accuracy/Limit of Errors: Standard: ± 1% or 4.5° C
Physical Properties: Type C thermocouples are capable of accurately measuring extremely high temperatures. However, they have no oxidation resistance, meaning they are only suitable for applications with vacuum, hydrogen, or inert atmospheres.
Applications: High Temperature Materials Manufacturing, Power Generation, Aerospace, Semiconductor Processing and Equipment, Military and Defense Testing

Type E Thermocouples

Material: Chromel (+) and Constantan (-)
Temperature Range: -454 – 1832° F (-270 – 1000° C)
Accuracy/Limit of Errors: Standard: ± .5% or ± 1.7° C, Special: ± .4% or ± 1° C
Physical Properties: Type E thermocouples are highly accurate with a fast response, even in sub-zero applications. They have the strongest signal and highest output of the base metal thermocouples and aren’t subject to corrosion at cryogenic temperatures (-238 – 460° F).
Applications: Gas Temperature Measurement, Cryogenics, Aerospace Industry, Applications with Magnetic Fields

Type J Thermocouples

Material: Iron (+) and Constantan (-)
Temperature Range: 32 – 1382° F (0 – 750°C)
Accuracy/Limit of Errors: Standard: ± .75% or ± 2.2° C, Special: ± .4% or ± 1.1° C
Physical Properties: Type J thermocouples are capable of accurate temperature monitoring in a vacuum or for inert materials. However, they are susceptible to oxidation at low temperatures or moist environments. While they are the least expensive general-purpose thermocouples, Type J thermocouples also have the shortest lifespan, and their accuracy will be permanently impaired if exposed to temperatures greater than 1400° F.
Applications: Plastic Manufacturing, Laboratory Processes, Ovens, Kilns, Furnaces

Type N Thermocouples

Material: Nicrosil (+) and Nisil (-)
Temperature Range: -450 – 2372° F (-270 – 1300°C)
Accuracy/Limit of Errors: Standard: ± .75% or ± 2.2° C, Special: ± .4% or ± 1.1° C
Physical Properties: Type N thermocouples have superior corrosion resistance and are capable of measuring high temperatures compared to other base metal thermocouples. However, they also have a slower response and lower sensitivity.
Applications: Refineries, Petrochemical Industry, Ovens, Kilns, Furnaces

Type K Thermocouples

Material: Chromel (+) and Alumel (-)
Temperature Range: -328 – 2282° F (-200 – 1250°C)
Accuracy/Limit of Errors: Standard: ± .75% or ± 2.2° C, Special: ± .4% or ± 1.1° C
Physical Properties: Reliable, accurate, inexpensive, with fast response across a wide rand of temperatures, Type K thermocouples are the most commonly used type of thermocouple. With oxidation resistance and radiation hardness, Type K thermocouples are extremely versatile. However, they shouldn’t be used in vacuum applications, low oxygen, or sulphuric environments.
Applications: Steel and Iron Industry, Petroleum Refineries, Nuclear Applications, Chemical Production, Ovens, Kilns, Furnaces

Type T Thermocouples

Material: Copper (+) and Constantan (-)
Temperature Range: -328 – 662° F (-250 – 350° C)
Accuracy/Limit of Errors: Standard: ± .75% or ± 1° C, Special: ± .4% or ± .5° C
Physical Properties: Type T thermocouples are extremely stable and capable of operating at extremely cold temperatures. However, it has a narrow temperature range compared to other thermocouple types.
Applications: Food Production, Cryogenics, Deep Freezing, Laboratory Processes

Noble Metal Thermocouples

Noble metal thermocouples use platinum alloys, making them accurate at extremely high temperatures – but also significantly more expensive!

Type B Thermocouples

Material: Platinum-Rhodium (+ and -)
Temperature Range: 32 – 3092°F (0 – 700° C)
Accuracy/Limit of Errors: Standard: ± 5% or ± .5° C
Physical Properties: Type B thermocouples are extremely accurate and stable at extremely high temperatures. They are corrosion-resistant and are suitable for oxidizing environments. However, they are susceptible to contamination and require appropriate protection.
Applications: Industrial Glass, Metal Melting and Pouring, Analytical Instrument Calibration, Nuclear Reactor Temperature Regulation, Semiconductor Processing and Equipment

Type R Thermocouples

Material: Platinum-Rhodium (+) and Platinum (-)
Temperature Range: 32 – 2642°F (0 – 1450° C)
Accuracy/Limit of Errors: Standard: ± .25% or ± 1.5° C, Special: ± .1% or ± .6° C
Physical Properties: With a higher percentage of rhodium, Type R thermocouples are more expensive than other noble metal thermocouple types, but also have a higher output and improved stability. They are resistant to oxidation as well as chemically aggressive material. However, they are susceptible to contamination and require appropriate protection.
Applications: Industrial Glass, Power Generation, Mining, Laboratory Processes, Temperature Sensors, Ovens, Kilns, Furnaces

Type S Thermocouples

Material: Platinum-Rhodium (+) and Platinum (-)
Temperature Range: 32 – 2642°F (0 – 1450° C)
Accuracy/Limit of Errors: Standard: ± .25% or ± 1.5° C, Special: ± .1% or ± .6° C
Physical Properties: Type S thermocouples are extremely similar to Type R thermocouples in regard to physical properties. However, a slightly lower percentage of rhodium makes Type S thermocouples slightly less stable.
Applications: Industrial Glass, Power Generation, Mining, Laboratory Processes, Temperature Sensors, Ovens, Kilns, Furnaces

Type P Thermocouples (Platinel II)

Material: Palladium-Platinum-Gold (+) and Gold-Palladium (-)
Temperature Range: 32 – 2543°F (0 – 1395° C)
Accuracy/Limit of Errors: Standard: ± .2mV (up to 1200° C)
Physical Properties: Type P thermocouples are designed to approximate the same curve as Type K thermocouples. They are extremely accurate and stable. Type P oxidation-resistant and can be used in inert atmospheres, but they are susceptible to contamination and require appropriate protection.
Applications: Regulating Gas Turbine Engines, Temperature Sensors, Ovens, Kilns, Furnaces

What Thermocouple Type Should I Use for my Kiln or Heat Treat Oven?

The type of thermocouple you should use for your kiln or heat treat oven largely depends on the temperature requirements of your firing schedules. Due to its durability, reliability, and accuracy across an extensive range, a Type K thermocouple is a popular choice for most kilns and heat treat ovens. Type K thermocouples are suitable for most heat treat applications.

However, some materials, such as porcelain, have temperature requirements that exceed the range for Type K thermocouples, in which case you may consider using a Type R or Type S thermocouple. The original TAP Kiln Controller by SDS Industries supports Type K, Type R, and Type S thermocouples. The TAP II, along with every other TAP Product by SDS industries, supports Type K thermocouples.

Pair Your Thermocouple with the Right Temperature Controller

The TAP and TAP II Controllers by SDS Industries are the most advanced, precise, and easy-to-use temperature 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 to allow you to easily manage and execute your kiln firing schedules.

We invite you to explore our selection of digital 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:

Posted on August 1, 2023August 8, 2023 by Brittany Gabel

Kiln Firing Chart for Pottery and Ceramics [Infographic]

When it comes to firing ceramics, different types of clays and glazes are rated for different temperatures. A kiln firing chart, also known as a cone firing chart, is a useful tool for understanding the effects of temperature on different types of clays and glazes, as well as determining what firing schedule setpoints should be used depending on the cone rating of the media you’re firing.

What Temperature Is Pottery Fired At? Understanding Different Types of Ceramics

What temperature is pottery fired at? Well, that depends. There a three main types of clay that are used to make pottery: earthenware, stoneware, and porcelain. Each of these has different temperature requirements, as well as different properties once fired.

1. Earthenware

Earthenware clay is the most common type of clay used in ceramic firing today. Earthenware is softer than the other types of clay, making it easier to work with and more forgiving. Earthenware also has the lowest firing temperature requirements, which is why it was the first type of clay used to make pottery during the early stages of kiln history.

A collection of fired earthenware pottery to demonstrate the qualities of fired earthenware — **Fired earthenware is porous and relatively soft. Earthenware ranges from white and gray hues to browns, oranges, and reds.**

Firing Temperature

Earthenware clay typically reaches maturity (or optimum hardness) between 1745° F and 2012° F, although some low-firing earthenware clays can be fired in temperatures as low as 1200° F.

Cone Rating

Earthenware is what’s known as a “low fire” clay. Earthenware clay can be fired from Cone 015 up to Cone 1, but Cone 04 is the average.

Physical Properties

Since earthenware is fired at lower temperatures, it typically remains porous, relatively soft (you can scratch it with a knife!), and still absorbs water. Glazes are often required to make earthenware harder and watertight.

2. Stoneware

Stoneware is a “mid-range” or “high fire” clay that requires higher firing temperatures and a longer firing schedule than earthenware. Once it has been fired, stoneware is hard, dense, and rocklike – hence the name!

A collection of fired stoneware ceramics, demonstrating its hard, rocklike texture — **Named for its hard, rock-like texture, fired stoneware is often gray or brown.**

Firing Temperature

Stoneware reaches maturity between 2000° F and 2400° F – hotter than lava!

Cone Rating

Stoneware is typically fired between Cone 2 all the way up to Cone 12, with Cones 7 and 10 being the most common for mid-range stoneware and high fire stoneware, respectively.

Physical Properties

Since stoneware is fired at higher temperatures, it has time to fully vitrify, or form a glassy, nonporous bond on its surface. Finished stoneware is durable, hard, and nonporous. Unlike earthenware, stoneware is waterproof once fired even without the use of glazes.

3. Porcelain

Originating in China in 1600 BC, porcelain is a “high fire” clay that produces extremely hard, shiny, often white or translucent ceramics. Also known as kaolin clay (named after Kao-ling hill in China, where it was mined for centuries), raw porcelain is extremely dense and difficult to work. Often, porcelain is mixed with other types of clay to improve its workability.

A collection of fired porcelain ceramics, demonstrating its hard, glasslike white exterior — **Fired porcelain is hard, smooth, and glasslike – notable for its white or translucent color**

Firing Temperature

Porcelain typically reaches maturity between 2381° F and 2455° F – however, pure kaolin reaches maturity at 3272° F!

Cone Rating

Porcelain clay is fired between Cone 10 and Cone 13.

Physical Properties

Once fired, porcelain is extremely hard and fully vitrified, making it watertight and non-absorbent. Porcelain is noted for its distinct white color.

Understanding Firing Cone Ratings

As we mentioned earlier, different ceramic materials and glazes have a cone rating. Firing cones, or pyrometric cones, are a simple pyrometric device that indicate kiln temperature. Firing cones melt when exposed to a certain temperature for a prolonged period of time. Different ceramics and glazes are given a cone rating to indicate the temperatures at which they’ll reach maturity.

Firing cones range from 022 to 14, with 022 being the lowest temperature and 14 being the highest. As you’ll see on the kiln firing chart below, when a firing cone rating has a ‘0’ in front of it, a lower number indicates a higher fire temperature.

However, for firing cones without a ‘0’ in front of their rating, higher numbers indicate higher firing temperatures.

Kiln Firing Chart [Infographic]

In the kiln firing chart below, you’ll be able to see which temperatures correspond with various cone ratings and materials. The color gradient indicates the incandescence of the kiln at various temperatures, and the column to right indicates how the physical properties of ceramic changes at each temperature.

Download PDF!

Reach the Right Setpoints on Your Kiln Firing Chart with Ease and Precision

The TAP and TAP II Controllers by SDS Industries are the most advanced, precise, and easy-to-use pottery 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 to allow you to easily manage and execute your kiln firing schedules.

We invite you to explore our selection of digital kiln controller, 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:

Posted on July 25, 2023July 25, 2023 by Brittany Gabel

Understanding Kiln Firing Schedules for Glass, Ceramics, Pottery, and Heat Treat

The primary function of a kiln controller is to help users input (and successfully execute!) their kiln firing schedules…but what is a kiln firing schedule? Below, we’ll be helping you understand kiln firing schedules, as well as how firing schedules differ for materials such as glass, ceramic, pottery, and metal heat treat!

Definition of Kiln Firing Schedules

A kiln firing schedule is a progression of steps, made up of temperature changes over specific time intervals, that a kiln moves through during a firing. Each step of a kiln firing schedule is made up of four components:

Step #: Also known as a ‘segment,’ step # represents the order in which the steps of the schedule occur.
Ramp Rate: Measured in degrees per hour, the ramp rate is the speed at which the kiln is heated up or cooled down.
Setpoint: Measured in degrees, the setpoint is the desired temperature the kiln reaches during each step.
Hold Time: Also, known as a ‘soak,’ hold time is the length of time (defined in days, hours, or minutes) the kiln stays at a specific setpoint before advancing.

Each of these components determines the properties of the finished ware once the firing schedule reaches completion. Even extremely minor variances in adhering to kiln firing schedules can have a major impact on the finished result, so it’s important to accurately input firing schedules into your kiln controller and to utilize kiln controllers that are able to automatically execute kiln firing schedules with extreme precision.

Example of a Kiln Firing Schedule

Kiln firing schedules, sometimes colloquially referred to as programs or firing schedules, can best be described as the road map the controller uses to execute a firing. While kiln firing schedules can string together as many steps as necessary to achieve the desired firing result, below we’ll be looking at an example of a three-step firing schedule:

Assuming the kiln starts at room temperature, or 70° F, the example schedule shown above will result in a firing that takes 5 hours and 24 minutes to complete. Below is a visual graph representing the firing profile of this schedule:

In this graph, we can see that the kiln follows a 500 degree-per-hour ramp rate from time 0 (when the kiln was started) to 950 degrees (the first setpoint). Once the setpoint is achieved, the controller regulates the temperature to keep the kiln at 950° for 30 minutes.

Once the hold time from the first step is completed, the kiln advances at a rate of 1200 degrees-per-hour to a setpoint of 1425° and holds there for 20 minutes.

Finally, the kiln moves to step three, cooling at a rate of 300 degrees-per-hour down to a setpoint of 700°. Because the hold time at Step #3 is zero, the kiln firing schedule is now complete!

See our article on Alerts and Alarms so you can be notified when your kiln firing schedule reaches certain firing points! 

Ramp/Hold vs Time-to Temp Schedules

Kiln firing schedules can also be expressed in different formats. The example above is the common Ramp/Hold format, which can also be described as a Ramp/Soak or Ramp/Dwell schedule. This is the most common kiln firing schedule format, and it is also the format that is supported by TAP Kiln Controllers.

However, kiln firing schedules can also be written in a Time-to-Temp format, which contains all of the same information but prioritizes the timing of the firing as opposed to the temperature of the firing.

When generating a Time-to-Temp schedule, you are, in effect, saying “I want to be at 950 degrees in 1 hour and 45 minutes.” At that point, the controller is responsible for converting the defined “Time-to-Temp” into a usable Ramp Rate. By saying we want to be at 950° in 1 hour and 45 minutes, and assuming we’re starting from 70°, we’ve essentially created a firing schedule with an implied ramp rate of 500 degrees-per-hour.

NOTE: Some controllers that use Time-to-Temp format do not report accurate ramp rate, which can affect outcomes of the firing schedule. For instance, a Time-to-Temp controller might report that your kiln went from 100° to 1250° in one minute, because that was what it was programmed to do, even though achieving that level of temperature change over that time interval simply isn’t possible.

Below is the exact same kiln firing schedule from before written in a Time-to-Temp format:

The firing graph for both formats would look exactly the same – and executing either format would yield the same outcome once the firing schedule reaches completion (assuming the controller was capable of converting the Time-to-Temp into an accurate ramp rate). The only difference is how the kiln firing schedule is expressed. What was defined in three steps in the Ramp/Hold format requires five steps in the Time-to-Temp format, despite yielding the same firing profile.

What Factors Does a Kiln Firing Schedule Depend On?

Kiln firing schedules are dependent on the material/media being fired, as well as the physical capabilities of the kiln. There is no one-size-fits-all approach to kiln firing schedules, as the material within the kiln will require its own unique schedule to achieve optimal results. Later in the article, we’ll be looking at examples of firing schedules for glasswork, firing ceramics, and metal heat treat.

Limitations of Kiln Firing Schedules

Now that you know the components of a kiln firing schedule, you should also understand the limitations. The physical capabilities of the kiln dictate certain physical boundaries that cannot be overcome. The material of the kiln, chamber size, power rating, and thermocouple gauge all contribute to the kiln’s demonstrated performance.

As kilns approach higher temperatures, their ability to heat at defined ramp rates begins to fall off. A kiln that can heat at a ramp rate of 3600 degrees-per-hour while at 200° will likely be unable to generate the same ramp rate at 1500°. This is a result of the kiln material and power rating.

Thermocouples are used to read the temperature inside a kiln chamber and communicate that temperature to the kiln controller. A kiln with an 8-gauge thermocouple will respond much slower to temperature input than a 20-gauge thermocouple. This can result in overshoot at low setpoints as the thermocouple needs time to “catch-up” to the heat that has been applied to the kiln.

Kiln Firing Schedules for Glass

While the kiln firing schedule example above was hypothetical, in this section we’ll explore actual kiln firing schedules for different types of glasswork techniques.

Please Note: Each of these schedules is for 90 COE glass. Additionally, each firing schedule will have to be adjusted according to your specific kiln, the size of your project, as well as the type of glass you’re using – some experimentation will be required, so please just use these as a general guideline.

For additional in-depth technical information about using your kiln to fire glass, please visit https://www.bullseyeglass.com/index-of-articles/.

Full Fuse Firing Schedule

A full fuse is when you use heat and time to combine two or more layers of glass to form one single solid piece of glass. The layers of glass fuse together – hence the name! Below is a full fuse firing schedule for projects that are smaller than 12”.

400°F/Hr to 1250°F – hold 30 minutes.
600°F/Hr to 1490°F – hold 10 minutes.
AFAP°F/Hr to 900°F – hold 30 minutes.
150°F/Hr to 7000°F – hold 0 minutes.
AFAP°F/Hr to 70°F – hold 0 minutes.

You can find temperature guidelines for additional glasswork processes here.

Glass Casting Firing Schedule

Glass casting is when you melt glass until it is soft and malleable enough to conform to a mold. The glass then hardens to create a glass object in the shape of the mold. Below is a glass casting firing schedule for a small open face mold cast:

100°F/Hr to 200°F – hold 6 hours.
100°F/Hr to 1250°F – hold 2 hours.
600°F/Hr to 1525°F – hold 3 hours.
AFAP °F/Hr to 1200°F – hold 4 hours.
50°F/Hr to 900°F – hold 6 hours.
12°F/Hr to 800°F – hold 1 minute.
20°F/Hr to 700°F – hold 1 minute.
72°F/Hr to 70°F – hold 1 minute.

Additional details about casting firing schedules can be found here.

Annealing Firing Schedule

Annealing glass is the process of stabilizing glass during the cooling process by holding it at a steady temperature to give it time to strengthen. COE 96 glass is typically annealed at a setpoint of 960°F. However, the size of the glass, its thickness, as well as the number of layers being used determines how long the anneal hold needs to be.

From the example of the Full Fuse Firing Schedule above, we highlighted the steps that involved annealing in green:

Notice that Step #3 has the kiln hold at the annealing setpoint 900°F for 30 minutes in order to give the fuse time to stabilize, and then Step #4 and Step #5 have the kiln slowly cooling down from the setpoint to the final temperature.

See our article Benefits of Using a Digital Controller for Glass Kilns for more information about using your kiln for glasswork!

Kiln Firing Schedules for Ceramics

Before getting into kiln firing schedules for ceramics, it’s important to know what Cone # the material you’re firing is rated for. This represents the setpoint at which the type of material you’re using is properly fired. So, for example, Cone 04 clay would need to reach a setpoint of at least 1945°F whereas Cone 6 Porcelain would need to reach a setpoint of 2232°F.

Please Note: All of these kiln firing schedules are for 04 Cone clay. Just like with glasswork, each firing schedule will have to be adjusted according to your specific kiln, the size of your project, as well as the type of clay, stoneware, or porcelain you’re using – some experimentation will be required, so please use these as a general guideline.

Candling Firing Schedule

Candling is the process of allowing clay to fully dry prior to high temperature ceramic firings. This involves heating your kilns to a low temperature for a prolonged period of time. Below is an example of a kiln firing schedule for candling your clay:

150°F/Hr to 150°F – hold 12 hours.

Simple, right? However, this is just to get the clay ‘bone-dry’ before firing it, since the natural moisture of the clay, if fired too quickly, can cause your project to crack and fissure!

Bisque Firing Schedule for Cone 04 Ceramics

A bisque firing is the process of turning clay into ceramics! Below is a slow bisque firing schedule for Cone 04 clay:

80°F/Hr to 250°F.
200°F/Hr to 1000°F.
100°F/Hr to 1100°F.
180°F/Hr to 1695°F.
80°F/Hr to 1945°F.

You’ll notice that this firing schedule doesn’t include any hold times. However, the total firing time is 13 hours and 26 minutes. So how does that work? In this case, the firing time is dictated by the ramp rate – or the amount of time it takes for your kiln to reach each setpoint in the firing schedule.

Glaze Firing Schedule for Cone 04 Ceramic

When firing pottery, it’s important to match the Cone # of your glaze to the Cone # of your clay. In this case, we’re using Cone 04 clay, which is a “low-fire” clay. Therefore, we’d want to use a glaze that’s in the Cone 06-04 range. In other words, the temperature of the glaze firing schedule shouldn’t exceed the temperature of the bisque firing schedule.

150°F/Hr to 250°F.
400°F/Hr to 1695°F.
100°F/Hr to 1945°F.

See our article on How to Use a Pottery Kiln Temperature Controller for more information on how to fire ceramics!

Firing Schedules for Heat Treating Metals

Just like with glasswork and pottery, kiln firing schedules for metal heat treat is extremely dependent on the type of material you’re using. But, additionally, it’s dependent on the qualities you want the finished metal to have. For heat treat, the rate at which you cool the metal has a significant impact on the molecular structure of the metal. For these examples, we’ll be working with 1095 steel.

Please Note: All of these kiln firing schedules are for 1095 steel. Just like with Each firing schedule will have to be adjusted according to your specific kiln or heat treat oven, the type of metal you’re using, its thickness, as well as the desired properties – some experimentation will be required, so please just use these as a general guideline.

You can find more information about setpoints and cooling rates for different effects on different types of metal here.

Normalizing Firing Schedule for 1095 Steel

Normalizing is a process where metal is heated to an extremely high temperature for a defined period of time and then either air-cooled or furnace cooled at a controlled ramp rate. Normalizing relieves internal stress and ensures uniformity, resulting in harder, stronger metals. Below is a normalizing firing schedule for 1095 steel:

AFAP°F/Hr to 1600°F – hold for 15 minutes.
Remove knife or blade from the oven and allow to air-cool.

Quench Hardening Firing Schedule for 1095 Steel

Quenching is the process where metal is heated and then cooled rapidly by dipping it into an oil, polymer, or water, resulting in very hard, very brittle metal. This increases the hardening of the metal (but also its brittleness). Below is a quench firing schedule for 1095 steel:

AFAP°F/Hr to 1600°F – hold for 15 minutes.
Remove knife or blade from the oven and quench in fast oil to 150°F.

Tempering Firing Schedule for 1095 Steel

After hardening, the metal is heated to a lower temperature to reduce excessive hardness and relieve internal stress. Tempering makes metals less brittle – it should be done within two hours after the steel cools from the quench hardening process. Below is a tempering firing schedule for 1095 steel:

AFAP°F/Hr to 400°F – hold for 2 hours.
Allow knife or blade to slowly cool – either air-cooled or within the oven.

You’ll notice that most heat treat applications have simple kiln firing schedules that only involve a single setpoint and aren’t dependent on ramp rate. For this reason, it might make sense to use a single setpoint controller for heat treat applications like the TAP & Go by SDS Industries.

Check out Guide to Choosing Heat Treating Controllers for more information about different types of heat treatments!

The Easiest Way to Precisely Execute Kiln Firing Schedules

The TAP and TAP II Controllers by SDS Industries are the most advanced, precise, and easy-to-use digital 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 to allow you to easily manage and execute your kiln firing schedules.

We invite you to explore our selection of programmable 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:

CTA: A Better Way to Manage and Execute Your Kiln Firing Schedules

Posted on July 11, 2023July 11, 2023 by Brittany Gabel

14 Types of Electric Kiln Temperature Controllers

When it comes to controlling the temperature of an electric kiln, there’s a wide variety of electric kiln temperature controller options. Below are 14 types of kiln temperature controllers – from old school analog kiln sitters to advanced digital kiln controllers for complex firing processes.

Types of Electric Kiln Temperature Controllers

1. Manual Kiln Temperature Controllers

When kilns became electric in the early 20th century, every electric kiln had manual controls. With manual kiln temperature controllers, users set the temperature of their kiln through a combination of analog dials and switches. However, manual kiln controllers cannot adjust the temperature of the kiln or advance through a firing schedule without direct user input.

This means that manual kiln temperature controllers require constant hands-on management and aren’t suited for executing complex firing schedules that require high degrees of precision. However, since they’re inexpensive and have a minimal learning curve for managing user inputs (using a manual kiln controller is a lot like using a kitchen oven), manual kiln controllers are still widely used today.

2. Kiln Sitters

The first major innovation to electric kiln temperature controllers was the invention of the kiln sitter in the 1950s. Used with manual kiln temperature controllers, the kiln sitter was the original limit controller. Limit controllers add kiln safety by ensuring a kiln shuts off when a certain temperature threshold is met. Kiln sitters accomplish this for manual kilns through primitive technology. A sitter cone, inserted in the kiln sitter, melts at a certain temperature causing the kiln to power off.

Illustration showing the components of a kiln sitter with labels. — **Although outdated compared to the automatic kiln controllers of today, the invention of the kiln sitter was a major early innovation in electric kiln temperature controllers.**

3. Automatic or Digital Kiln Temperature Controllers

In the mid-1980s, the automatic kiln controller was invented. Automatic kiln controllers significantly streamline the firing process by managing the temperature of an electric kiln without user input. Also known as digital controllers, automatic kiln controllers allow users to program their device to reach the right temperatures at the right times without their direct oversight.

Automatic kiln controllers are far more precise than manual kiln controllers and leave less room for user error, making them more suitable for more complex firing schedules like those used for glasswork or some types of ceramic firings.

The first automatic kiln temperature controllers used analog inputs and had extremely complicated menus and user interfaces! However, over the last several decades automatic kiln temperature controllers have evolved massively. Today’s most advanced automatic kiln controllers are extremely easy to use and include responsive touchscreen controls, an intuitive UI, full control and extensive diagnostics, real-time monitoring and data, Wi-Fi connectivity, and mobile app integration.

**The TAP Kiln Controller is the most advanced automatic electric kiln temperature controller on the market today.**

4. 3-Key Kiln Temperature Controllers

For early automatic kiln controllers, users had analog buttons (or keys) to navigate menus and set the temperature of their electric kilns. A 3-key kiln temperature controller has three keys which the operator uses to program the kiln. As you can imagine, this can get extremely complicated! However, 3-key kiln controllers are still sold by certain manufacturers.

5. 12-Key Kiln Temperature Controllers

A 12-key kiln temperature controller includes additional keys, which makes programming an electric kiln slightly more convenient. However, compared to other more advanced electric kiln temperature controllers, 12-key controllers are still complicated to use and don’t present the best user experience.

(Note: If you’re still using a 3-key or 12-key controller, conversion kits allow you to easily replace them with more advanced digital touchscreen kiln controllers.)

6. Touchscreen Kiln Temperature Controllers

In 2015, SDS Industries released the TAP Kiln Controller which was the first commercially available electric kiln temperature controller to use a touchscreen user interface. Touchscreen kiln controllers make programming and monitoring temperature for an electric kiln much more intuitive and user friendly than 3-key and 12-key controllers.

With touchscreen kiln temperature controllers, navigating menus and creating firing schedules can be accomplished with just a few finger presses, and a larger screen and graphical UI allows users to see more details about their firing schedule and view detailed firing charts and diagnostics.

7. Multi-zone Kiln Temperature Controllers

Electric kilns come in two general configurations: single-zone and multi-zone kilns. Electric kilns are heated by resistive metal elements, much like those seen in a toaster oven. For single-zone kilns, all of the kiln’s elements respond to input from a single thermocouple. For multi-zone kilns, multiple thermocouples are used to sense temperature in different sections of the kiln and adjust power to the elements accordingly.

Multi-zone electric kiln temperature controllers, such as the TAP Kiln Controller, include multiple thermocouple inputs to set specific temperatures for different sections of the kiln, allowing users to obtain consistent firing results in a single large kiln.

8. Single-zone Kiln Temperature Controllers

Single-zone electric kiln temperature controllers, on the other hand, only have a single thermocouple, which is used to control all of the elements of a kiln and achieve a single temperature. Currently, the TAP II Kiln Controller is the most advanced and easy-to-use temperature controller for single-zone electric kilns and ovens on the market today.

**The TAP II Controller is an advanced single-zone kiln temperature controller, with an intuitive, graphical UI, built-in Wi-Fi, and integration with the TAP Kiln Control Mobile App.**

9. Internet Kiln Controllers

Internet kiln controllers, or Wi-Fi kiln controllers, utilize a Wi-Fi signal to allow users to control and monitor their kiln from their mobile device or tablet. Internet kiln controllers give users far more flexibility and freedom when it comes to operating their electric kilns, allowing them to remotely create, modify, and execute firing schedules, monitor their kiln with real-time updates and push notifications, and skip steps and abort firings.

All of the TAP Kiln Controllers by SDS Industries have Wi-Fi capability and pair with the TAP Kiln Control Mobile App to give users almost complete remote control of their electric kiln.

The TAP Micro is an internet kiln controller that users control entirely from their smartphone or tablet. — **The TAP Micro, now available for pre-order, is an internet kiln controller that users control entirely from their smartphone or tablet!**

10. Single Setpoint Kiln Temperature Controllers

Single setpoint kiln controllers are a simplified electric kiln temperature controller option that allows users to program their kiln to reach a single setpoint (or temperature) for an indefinite hold. Not all firing schedules require multiple setpoints or specific ramp rates (the speed at which a kiln heats up). Single setpoint electric kiln temperature controllers are ideal for users who are making blades, knives, or doing other heat treat processes, or for glassblowers and flameworkers who are using pick up ovens.

11. Limit Controllers

Limit controllers, also known as high limit controllers or safety limiters, are redundant temperature monitoring devices that allow users to pre-program their electric kiln to automatically shut off if the kiln exceeds a specified temperature. While limit controllers usually aren’t suited to be the primary control method on an electric kiln, they are an important part of kiln safety and can protect you, your equipment, and your property in the case of relay or system failure.

The TAP Monitor is the most advanced limit controller and digital pyrometer, allowing users to add precise, remote, real-time digital temperature readings and redundant safety shut-off to any kiln or oven. — The TAP Monitor, now available for pre-order, is the most advanced limit controller and digital pyrometer, allowing users to add precise, remote, real-time digital temperature readings and redundant safety shut-off to any kiln or oven.

12. Process Controllers

A process controller is an automatic electric kiln temperature controller that employs a closed-loop digital feedback system to control and regulate the temperature of industrial control applications more precisely. Process controllers use a mathematical formula to calculate the difference between the input temperature and the current temperature of the application. The process controller then adjusts the output to compensate for the detected changes in the system, ensuring that the current temperature is as close to the expected temperature as possible.

TAP Kiln Controllers utilize PID (“Proportional Integral Derivative”) control algorithms to ensure precise schedule following with the fastest response with minimal overshoot and limited steady-state error.

13. ICS Kiln Controllers

ICS stands for Industrial Control System. An ICS kiln controller is a type of process controller that is rated for industrial applications. Industrial kilns are large and high-powered and require extremely high degrees of precision and consistency, usually accomplished by a control algorithm.

14. Standalone Automatic Kiln Controllers

How do you convert a manual electric kiln to automatic controls? A standalone automatic kiln controller is a plug-and-play solution to upgrade a manual kiln to digital controls. All you have to do is run the thermocouple attached to the standalone kiln controller to the interior of your kiln and plug your electric kiln into the standalone unit. This enables a standalone automatic kiln controller to bypass your manual control system, enabling you to enjoy all the benefits of an advanced digital touchscreen controller.

A table top standalone kiln controller allows you to easily upgrade a manual kiln to digital controls. — **TAP Standalone Automatic Kiln Controllers allow users to easily upgrade their manual kiln to automatic controls.**

Enjoy the Most Advanced, User-Friendly Electric Kiln Temperature Controllers

The TAP and TAP II Controllers by SDS Industries are the most advanced, precise, and easy-to-use electric kiln temperature controllers on the market today. With responsive touchscreen controls, an intuitive graphical UI, and integration with the TAP Kiln Control Mobile App, TAP Kiln Controllers can pair with any relay-controlled kiln or oven.

We invite you to explore our selection of electric kiln temperature 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:

Posted on July 3, 2023August 3, 2023 by Scott Shannon

A Complete History of Kilns

For millennia, humans have been using kilns to fire pottery, ceramic, glass, brick, limestone, grain, metal objects, and other materials. It’s not hyperbole to say that the history of kilns is the history of civilization. Dating back to the rise of agriculture in the Neolithic Age, humans have been using kilns to create the objects they need to support their community – from baking breads and cereals, to creating containers for grain and waters, crafting blades, knives, and tools, and creating fertilizer, mortar, art, and ornamental objects.

Throughout the past 10,000 years, the kiln has undergone many iterations and advancements, resulting in the modern industrial and at home kilns we use today. Today, we’ll be looking at the rich history of kilns from around the globe!

The Early History of the Kilns: 8000 – 6000 BC

The first kilns date back to approximately 8000 BC. Originating in the Near East, early kilns were pit fire kilns – consisting of holes or trenches dug into the earth where wares were placed and then surrounded and covered by wood or other combustible material. While this design was thermally inefficient, unstable, and unpredictable, the insulation from the earth allowed pottery to reach high enough temperatures to fire at least some of the time.

These early pit fire kilns were often temporary structures – and we only know they existed based on the remains of pit fired pottery dating back to this time period. However, the earliest kilns were prone to failed firings and fired pottery was often brittle.

A pit fire kiln. — ***The pit fire kiln was the earliest iteration of the kiln.***

The First Known Kiln: 6000 BC

The earliest known surviving kiln dates back to 6000 BC at the Yarim Tepe site in modern day Iraq. This kiln, which still utilized an earthen firing chamber, represented a major advancement in kiln technology. The kiln was double-chambered, with a clay grate placed over the firing chamber for stacking wares – and its remaining walls suggest that it was dome-shaped at the top to create an updraft and prevent thermal loss (a design also known as a beehive kiln).

In other parts of Mesopotamia, the design of chambered kilns continued to evolve over the next few millennia to be more thermodynamically efficient, allowing for greater volumes of pottery to be fired at higher temperatures.

Early Advancements in Kiln Technology: 3000 – 300 BC

By approximately 3000 – 2500 BC, the ancient Egyptians had begun using vented chambers that allowed wares to be fired while keeping them completely separate from the fuel source. These kilns were built vertically, with an open fire at the bottom that could be stoked to regulate temperature. This design allowed the fire to receive more oxygen while still remaining controlled and thermodynamically efficient.

By the 18th Dynasty (1550 – 1292 BC), the Egyptians had begun firing glazes for pottery and creating early glasswork to imitate precious stones such as turquoise.

An example of ancient Egyptian ceramic glaze. — **Ancient Egyptians pioneered the use of glasswork and ceramic glazes.**

The ancient Greeks (3000 BC – 300 BC) expanded on the design of Mesopotamian kilns, primarily favoring beehive constructions. Greek kilns were built partially into the earth, with an underground firing chamber. They used clay, and later brick, to construct additional chambers for piling vases and smoke collection.

Ancient Grecian pottery. — **Examples of ancient Grecian pottery.**

The Rise of Industrial Kilns: 1600 BC – 500 AD

The Romans (625 BC – 476 AD) refined Greek kiln design, adding air flow piping to keep smoke from coloring the fired products, as well as chimneys to improve draft. Improved building materials such as brick and concrete allowed the Romans to build large-scale industrial kilns that were capable of firing up to 40,000 ceramic vessels at a time! The Romans used these industrial kilns to create the clay tile they used throughout their empire.

The remains of an ancient Roman industrial kiln in Morgantina. — **The remnants of an ancient Roman industrial kiln in Morgantina, Italy.**

The Romans are also attributed with the creation of lime kilns, which they introduced to Britain. Burning limestone was used to create mortar and concrete, allowing for the creation of the famous structures of the Roman Empire. (Later, this technology was used for construction during the Middle Ages – and then to create fertilizer during the 18th century).

In Great Britain, early examples of climbing kilns have been found from during the time of Roman occupation. Climbing kilns (or tunnel kilns) were long, multichambered kilns built into hillsides. A fire would be lit at the bottom and, since heat rises, the temperature of the kiln would increase with greater regularity, allowing for greater quantities of pottery to be fired.

Meanwhile, across the world, the Chinese had already perfected the art of climbing kilns. “Dragon kilns” as they were known in China, first began appearing during the Shang Dynasty (1600 – 1046 BC). By the Common Era, “dragon kilns” were widespread throughout China, sometimes reaching up to 60 meters long and capable of consecutively firing 25,000 pieces. Chinese “dragon kilns” were extremely well designed and capable of reaching up to 1400° C in order to fire stoneware and porcelain.

An example of ancient Chinese porcelain (c. 14th- 11th centuries BC) — **By c. 1400 – 1100 BC, ancient Chinese kiln technology was advanced enough to fire porcelain.**

An Increase in Efficiency and New Techniques: 400 AD – 1700 AD

The Japanese further refined Chinese kiln construction beginning in the 5th Century, creating the famous Anagama and Noborigama kilns. Over the next millennium, Japanese kilns evolved to become extremely thermodynamically efficient. This efficiency allowed the Japanese to later craft the ornate, sophisticated porcelain pieces the country became famous for – the lineage of using traditional techniques in Japan for firing porcelain and ceramics is still alive today!

**A climbing kiln in Kyushu Island, Japan.**

In Europe, throughout the Medieval and Renaissance periods, kilns continued to be an important part of day-to-day life. By the Renaissance, potters had begun using muffle kilns (or reduction kilns) for second or third firings, allowing for the application of additional glazes and majolica. These additional firings allowed for the creation of lusterware, which has iridescent metal glazes and was highly valued during that time period. (However, it’s worth noting that this technique had already been discovered almost 800 years earlier – with lusterware first appearing in modern day Iraq in the early 9th century).

Kilns During the Industrial Revolution: 1700 AD – 1900 AD

As with many industries and manufacturing processes, the Industrial Revolution had a major impact on kiln design. Coal (or anthracite) replaced wood burning and charcoal as the primary fuel source for kilns and ovens. In England, bottle kilns, famous for their bottle-shaped flutes, became commonplace. Despite their inefficiency, bottle kilns were widely used into the mid-20th century.

Bottle kilns in Stoke-on-Trent, England — *Named for their distinctive bottle-like shape, bottle kilns were widely used for industrial processes in England during the late 18th and 19th centuries.*

During this time period, industrial kilns grew in scale – with large factories capable of mass-producing ceramics and other fired goods.

The Rise of the Modern Kilns: 1900 AD – Present

During the Industrial Age, coal-burning kilns were slowly phased out for gas kilns and electric kilns – and the modern kiln was born! Compared to prior kilns, gas kilns and electric kilns were extremely efficient and capable of reaching high temperatures. These new fuel sources and advancements in technology allowed kilns to become extremely big and extremely small – from industrial kilns that are hundreds of yards long to hobby kilns that are about the size of a toaster oven!

Although early modern kilns were all manually controlled, the use of gas and electricity allowed for far more control and precision in regulating kiln temperature, which allowed for more complex firing processes such as those needed for glasswork.

In the 1950s, the kiln sitter was invented, which allowed for kilns to automatically shutoff once they reached a specified temperature.

The Automatic Kiln Controller Revolution: 1986 – Present

The Digital Age brought with it the invention of the automatic kiln controller, which could be programmed in advance to carry out entire firing schedules without user input. While early automatic controllers were complicated and difficult to operate, they still significantly streamlined the firing process.

In 2015, SDS Industries revolutionized the automatic kiln controller industry with the release of the TAP Kiln Controller – the first commercially available consumer kiln controller to utilize an intuitive, graphical user interface. Using touchscreen technology, the TAP Kiln Controller allows users to easily operate their kiln and create, edit and save an unlimited number of firing schedules and steps. Additionally, the TAP Controller allows users to quickly check the status of their kilns with easy-to-read indicators and push notifications to their mobile devices.

User Interface from a TAP Digital Kiln Controller — **SDS Industries released the TAP Kiln Controller in 2015.**

In 2017, SDS Industries released the first iteration of the TAP Kiln Control Mobile App, which allowed users to remotely monitor and control their kiln from their mobile device – another major leap forward for the kiln control industry. Since then, SDS Industries has continued to be at forefront of kiln control innovation with updates to their mobile app, the release of TAP II Controllers with built-in Wi-Fi integration, as well as the upcoming releases of TAP Monitor, TAP & Go, and TAP Micro.

Enjoy Most Advanced, User-Friendly Automatic Kiln Controllers

The TAP and TAP II 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: