Tips and Tools: Thermocouple Stilts Allen Chen

Appears in the March 2021 issue of Ceramics Monthly.

This DIY version of a simple but seldom-considered support for high-fired glaze ware combines engineering and repurposed materials.

I often think about (obsess over) the amount of time and energy that it takes to manufacture the tools we use in the studio. For example, the thermocouple in our kiln that served consistently and courageously under fire for the past 4 years was purchased for $16 plus shipping. But the chrome, nickel, and copper materials used to make this product were mined from the earth, processed, and fused into a resilient alloy. The materials, along with the research, technology, and energy consumed in making this part are responsible for ensuring our kilns at school turn off precisely at cone 04. Even after more than 100 firings and repeated (accidental) bumps from the edge of a kiln shelf during loading and unloading, the thermocouple still manages to work.

Gearing Up

Once a thermocouple degrades and stops working (see 1), with some modification, it can continue be used in the studio as pin stilts to hold up glazed work during firings.

To begin, the first step requires straightening out the thermocouple (see 2). Sandwich the metal rod between two plywood boards and roll it back and forth with firm pressure (3). Next, while wearing safety glasses, take the straightened metal rod to a bench grinder or a belt sander to sand the tip into a sharpened point (4). Measure 1 inch from the point and cut through the rod (5). I make my pins 1-inch-long sections so that ¼ inch of the point will stick out once embedded in a coil of clay. Repeat the grinding and cutting process for the length of the thermocouple rod to create multiple pins. I was able to harvest about 9 of these pins from the 10-inch-long thermocouple.

Now, it’s time to stick the pins into coils of clay so they stand upright. The simplest way to do this is to roll a coil ¾ inch thick, cut a 2–3-inch section, and stick the pins into the coil vertically as straight as you can (6).

I like to stick in 2 pins per coil about 1¼ inches apart; it’s important to stick the pins in all the way down through the coil (so it hits the work surface) and not move the pins again. You can pinch the clay so that it squeezes the pins and reinforces a stable shape. I did this by pushing down the two ends of the coils with my thumbs as well as the center (with a round stamp) (see 7). I use a dependable clay body that I learned about in graduate school, Bill Kremer’s Notre Dame Class Mix. Dry the stilts thoroughly and fire to cone 10 before using.

So far I’ve used these stilts in about a dozen firings to cone 11. The pins are still sharp and glazes chip off easily with a light sanding with a metal file. I haven’t tried using these in a wood kiln or a soda kiln, but I’m looking forward to trying them out and reporting on the results.

Why don’t I just spend $5 and buy commercially made stilts? I think it has something to do with an appreciation for the energy that was put into the making of an object. I have a tough time throwing an item in the trash when I feel it still has worth in use. Repurposing an item that’s exhausted its original function gives me the satisfaction of creating something new of value. Furthermore, this kind of thinking that has led to such great inventions made out of other repurposed materials such as milk-jug scoops, sock masks, and the many DIY homemade gadget ideas found on Pinterest!

the author Allen Chen was born in Taiwan, grew up in California, and now lives in beautiful Hattiesburg, Mississippi, and teaches at the University of Southern Mississippi.