Advice for Keeping A Kiln Log

Keep a kiln log to get consistent results and more!

keeping a kiln log

With the ease of electric kilns, many potters forego keeping a kiln log. But there are plenty of reasons to do it. Historically, I have not been the best record keeper when it comes to making pots, and I have been burned many times due to my less-than-stellar memory.

In today’s post, an excerpt from the March 2020 issue of Ceramics Monthly, Vero Pepperrell shares benefits of keeping a kiln log and advice on what to track. Vero has inspired me to turn over a new leaf and I hope she inspires you too! – Jennifer Poellot Harnetty, editor.


Each time I switch the kiln on and hear the first few clicks of the relays, I grab my little black binder. In it, I jot down the details of the firing, for a kiln filled with promise and possibilities.

There are many reasons to keep a kiln log, from the practical to the whimsical. Here’s why I believe it’s a valuable tool in your studio.

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The Experimental Reasons

There are so many variables in ceramics: the choice of clay, the way it’s used for throwing or handbuilding, the bisque-firing temperature, the glazes used alone or in combination, and the glaze schedule used for the final firing.

Given that I can barely remember what I had for breakfast, the odds of remembering every detail of a firing are low, to say the least. In my kiln log, I note the firing schedule used, the temperatures reached, and any holds or slow cools. This is helpful in explaining why a glaze turned out the way it did. In a separate section of the kiln log, I keep a list of the standard schedules used and any adjustments made over time. Under a third tab, I scribble notes about which glaze-firing combinations have been successful, which ones look terrible, and what might be a fun experiment next time.

1 Noting the contents and results of a kiln firing, supervised by the cheerful kiln gods.

Whether you’re experimenting with your own glaze recipes or are exploring the possibilities of commercial glazes, you’ll be grateful to have notes to come back to when you find a magical combination you love.

The Technical Reasons

Kilns may seem bulletproof (and kind of are), but they contain parts that degrade over time. The elements, thermocouple, relays, and other kiln parts have a limited lifespan, so keeping a log lets you know how many firings have been done since the last time the elements were changed. Aside from unfortunate major mishaps, a kiln’s performance will slowly decline over time. It may take longer to reach temperature, or one area of the kiln may become cooler than the rest.

Being in tune with your kiln is so important. My kiln is fairly small, so I can fire often with fewer pieces; consequently, an unexpected outcome from a firing is less impactful than it might be in a larger kiln with more work. Regardless of kiln size, the better you can predict the outcome of your firing, the less likely you are to have a disappointing firing.

2 Was the kiln overfired? Keep track of firing schedules to improve the results next time.

Using cone packs is the most reliable way to get reproducible results. In a recent firing, I had extended the hold time at the top temperature in order to reach cone 6, but the result was overfired slightly (see 2), which I then noted in my kiln log to make adjustments next time.

The Emotional Reasons

Going back through a kiln log is like traveling through time. I love looking back at scribbles of the first steps when I launched my business, Along The Lanes: the first load where I solved my pinhole problem (there’s a note with a big “woohoo!”); the first firing with gold luster, where I was terrified it would be wasted (it turned out great); and that week where I fired the kiln every single day! We progress faster than we give ourselves credit for, and it’s a confidence boost to look back and see how much we’ve learned.

Start Your Own Kiln Log and Glaze Log

My kiln firing log and glazing log templates can be downloaded here: https://alongthelanes.com/pages/resources.

Both logs are fairly self explanatory. They include the date, number of firings done (in that kiln or on that particular set of elements, as you prefer), the type of firing (bisque, glaze, luster, or other, such as decals or sintering), the program used, the contents, and any relevant notes.

3 Fleeting scribbled notes eventually get lost. I’ve named each of these glaze combinations, saving photos like this one in an album on my phone. The application of each layer of glaze is noted in detail in my glaze log for future reference so that I can easily replicate my favorite ones (and avoid repeating the unpleasant ones).

I would suggest adding blank pages to jot down your favorite firing schedules, glaze combinations you’re dreaming of trying, doodled shapes of pieces you’d like to make, and so on. The more you use your kiln log, the more useful it becomes!

the author Canadian-born Vero Pepperrell lives in the Cambridgeshire countryside in the UK. She’s passionately dedicated to trying every craft on the planet, from knitting and sewing to painting and spoon whittling. In recent years, she has spent every spare moment throwing or handbuilding clay. She shares her adventures online at alongthelanes.com.

Comments
  • Laurie D.

    I also find helpful to make an outline of the kiln on my log, with the height of the posts I used for shelving and whether it was a whole shelf or a half shelf. After the firing I record the results of the cones and where they were on the shelf. This helps me see if there’s a cool spot in my kiln.

  • Keith .

    I agree logging each firing is important. I routinely record when the firing began and ended, the length of time and whether the kiln was heavily loaded or only partially full. This give me a warning that my elements may be getting too old as the length of similar firings has grown. I also note the time and temperature each time I check the cool down process, so I can estimate how long before it is ready to open and unload.

  • Erica P.

    Great advice. I also make a note of how long the firing was so that in the future I can plan to be in the studio when the kiln should reach temperature and shut off (just in case it doesn’t). If I need to I can delay the time that the firing starts.

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