You have read 1 of 3 of your complimentary articles for the month.
For unlimited access to Ceramics Monthly premium content, subscribe right now for as low as $4.85/month.
Yes, I want to subscribe to Ceramics MonthlyNot right now. Continue to article.
We understand your email address is private. You will receive emails and newsletters from Ceramic Arts Network. We will never share your information except as outlined in our privacy policy. You can unsubscribe at any time.
Subscribe to Ceramics Monthly
This guide, written for teachers but useful to all ceramic artists, provides information on basic kiln maintenance to ensure the longevity of this essential studio equipment.
Kiln Check-Up and Preventive Maintenance
At the beginning of the school year, and periodically throughout the rest of the year, do a full check-up on your kiln. Performing preventive maintenance will increase the life of the kiln and decrease chances of kiln failure. Some things to look for are: loose bricks, cracks in the floor and lid, rusty switches or parts, plug and wall electrical issues, thermocouple cracks or bending, loose wire connections, and worn-out kiln elements. If the kiln is manually operated, frequently check the switches and kiln sitter as well. The kiln should be installed on a level surface or leveled appropriately. If you have a kiln sitter, this is especially important. The kiln sitter should be recalibrated regularly. Your manual should have information to guide you through this. If you have any questions or concerns about your kiln, contact the manufacturer’s customer service department.
Before loading precious work into the kiln, check that your elements are in working order and do a test firing. If you routinely care for your kiln, this will be the most common fix since elements are like car batteries and wear out over time and need replacement. Keep a kiln log to record firings, making note of the firing time. If the kiln takes longer, or you have varied results, you might have an element or relay that needs to be replaced. To check your elements, turn on the kiln and peek inside. If all the elements light up, they are working. If they are not glowing red or if the firings have gotten a lot slower, they might need replacement. It could also be the relay that is responsible for switching the power on to your kiln’s elements, but the elements are a good place to start. I recommend replacing the elements all at once. Make a note or record of when this was done to reference in the future. Have extra elements, relays, and a thermocouple available so if they need to be changed, it can be done in a timely manner. This will prevent you from placing an order and waiting for budget approval or shipping in the middle of a semester when you’re already riddled with deadlines and a tight class schedule.
Before each firing, check to make sure your kiln’s floor and elements are clean and free of debris. If needed, vacuum using a vacuum with a HEPA filter. When loading, take care to protect the brick, elements, kiln sitter, and thermocouple. Carefully load shelves without hitting the side of the kiln and do not lean over the edge or on the bricks.
It is not uncommon for kilns to error. Error codes shown on a kiln’s control panel should not be ignored as they are the kiln’s form of communication. It is helpful to keep a cheat sheet with the error codes for your kiln nearby.
What is kiln wash? Kiln wash is typically a mixture of two or more refractory materials that are mixed with water and applied to kiln shelves to protect them from glaze drips. When applied correctly, it creates a barrier between the clay, glaze, and the shelves, ultimately protecting them from damage. Usually, kiln wash consists of 50/50 alumina hydrate and kaolin (EPK kaolin is most commonly used in kiln wash recipes), although there are other recipes available (the recipe that I recommend is listed above). Premixed dry kiln wash can also be purchased from a ceramic supplier. If you purchase premixed kiln wash, it often comes in a twist-top container that’s great for long-term storage.
What materials are needed to prepare your kiln shelves? Dry materials, water, a container labeled “kiln wash,” dust mask, safety glasses, scraper, sponge, clean bucket of water, and a thick, wide paintbrush or a small paint roller.
How do you make kiln wash? Wear a respirator and work in a well-ventilated area. Weigh out your ingredients and place them in a bucket with water. Mix the materials into a light cream consistency, adding water as needed.
How to prepare the shelves? First, prepare the shelves by removing glaze drips and uneven layers of kiln wash. Do this by scraping or grinding as necessary while wearing protective eyewear. Remove any dust with a clean, wet sponge. Always wear a respirator while grinding shelves and applying kiln wash.
How do you apply it? Apply the kiln wash liberally, covering the entire top surface of the shelf. Do not apply it to the sides of the shelves as it can fall off during a firing and adhere to glazeware. Use a clean, wet sponge to wipe any kiln wash off from the sides. Use a wide, thick brush or a small paint roller to apply the kiln wash. This is more efficient, especially if you are applying kiln wash to several shelves.
What if only a little piece has come off? If the shelves have small amounts of loose kiln wash, you can apply fresh wash to the affected areas. You may need to apply a little bit at a time, let it dry, and then apply more to build up a layer that is even and the same thickness as the wash on the rest of the shelf.
How to store kiln shelves? It is best if you have a place to let the shelves dry before you put them away. When you store the shelves, always place them standing up vertical, wash side to wash side, and back side to back side. This will help prevent wash from attaching to the underside of a shelf. If this happens, the kiln wash can drop down onto the art below and embed into the glazed surface.
How often do I need to apply kiln wash? This varies widely depending on how often you use your kiln.
For detailed instructions, please see the companion video, Teaching Clay in the Classroom: Part 1.
the author Excerpted and adapted from Teaching Clay in the Classroom by Jeni Hansen Gard. This book and companion videos are available in the Ceramic Arts Network Shop at ceramicartsnetwork.org/shop.
Illustrations by Gunyoung Kim.
June/July/August 2025: Table of Contents
Must-Reads from Ceramics Monthly
Unfamiliar with any terms in this article? Browse our glossary of pottery terms!
Click the cover image to return to the Table of Contents