Tips and Tools: Keeping a Kiln Log Vero Pepperrell

Appears in the March 2020 issue of Ceramics Monthly.

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.

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.

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.

Using cones 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 travelling 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.

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.