Different chemistry, same truth: Lessons in balance from clay bodies and human bodies

Aug 31

The rain outside was steady, the kind of rain that blurred streetlamps into soft halos. Inside Blue Dog Ceramics, the sound had a rival—the dull, rhythmic thwack of the pug mill chewing through a batch of reclaim clay. Every pulse from the machine echoed through the concrete floor, as steady as a heartbeat.

I was wiping slip from my hands when Charlotte walked over from the corner. She had been perched on a stool, sketchbook open, the lamplight slicing her profile into planes of shadow and gold.

Charlotte dipped her hands in the reclaim bin once, pulling at lumps of half-dried clay like she was searching for a lost diamond. She asked me, “Ken, why don’t we just use clay straight from the ground?”

I told her a clay body isn’t just one thing—it’s a recipe, a blend. Pure kaolin might be too stiff and chalky. Ball clay is smooth but shrinks too much on its own. Feldspar, silica, grog—they all step in like players in a band. Together they balance each other, making a clay that throws well, dries without cracking, and fires to strength. A clay body’s no different. It’s not the clay itself—it’s the body we build from it.”

Charlotte just nodded, pressing a lump flat in her palm. “So it’s not the ingredient, it’s the harmony,” she said. “Ok, riddle me this—what do fluxes in a glaze have in common with electrolytes in the human body?”

Her tone was curious but sly, the way she often baited conversations when she already had an idea simmering. Charlotte liked mysteries. She liked putting pieces together.

Thwack

I leaned back against the worktable, listening to the pug mill grind on. “That’s a good one,” I said. “But is seems like you already have an idea.”

She frowned, then smiled just enough to admit she knew the game. My teaching style—at least the way she saw it—wasn’t about dropping answers. It was about nudging, letting the student take the steps until the pattern revealed itself.

“Fluxes move things,” she began slowly. “They make silica and alumina melt where they wouldn’t otherwise. Electrolytes… they make the body work the same way. Sodium, potassium, calcium—without them, nothing flows. No nerves fire. No muscles contract.”

I nodded, letting her words linger. “So what does that tell you?”

“That balance matters,” she said after a pause. “In a glaze, too much sodium and the surface runs off the pot. In a body, too much sodium and you’ve got hypertension. Too little calcium and your glaze won’t mature—too little calcium in the body and your bones weaken.”

The pug mill thwacked on, underscoring her logic.

Charlotte was scribbling as I spoke, her pencil tracing circles and arrows between glaze oxides and blood ions. The analogy wasn’t just neat—it was precise.

“Ken,” she said, “isn’t it strange? A pot and a body, both held together by the same principle. Just different chemistry, same truth.”

“Not so strange,” I said. “Nature likes patterns. The trick is whether we notice them.”

She tilted her head. “But what about when things go wrong? In clay or in flesh?”

That was the heart of it—her dilemma. She wasn’t asking just about glazes anymore.

“Think of the pug mill,” I said, nodding toward the machine as it pooped out another slug of clay. “Every cycle blends the scraps, evens the moisture, forces chaos into order. That’s balance in action.

“In clay, the balance is silica, alumina, and flux. In the body, it’s water, electrolytes, and cell membranes. If one player gets too loud, the music falls apart.”

Charlotte looked at the clay as if it were a patient on a hospital bed. The pug mill gave another steady thwack, like a pulse.

“So the answer,” she said, almost whispering, “is that both clay and body live or die by equilibrium. Without it, nothing holds.”

I smiled. She’d solved her own riddle.

The rain outside softened to a drizzle. Charlotte shut her notebook and tucked her pencil behind her ear.

“You know, Ken,” she said, standing, “maybe that’s what we’re all after. Recipes that hold together—whether it’s a glaze on a pot or electrolytes in a bloodstream.”

She scratched a clump of clay from her sleeve and looked around the studio with that half-smile she liked to flash on success.

“Balance,” she said. “in clay bodies, glaze recipes, and in life.”

The kiln ticked as it cooled, the studio breathing in rhythm. And in that quiet, I thought she had it exactly right.

Thwack.

A Gentle Breakdown

Fluxes in glaze chemistry are oxides—sodium, potassium, calcium, magnesium, zinc, lithium, boron. Their job is simple but critical: they lower the melting point of silica and alumina so the glaze can melt and form glass. Without flux, you’d have a bucket of sand that refuses to melt even in a white-hot kiln.

But fluxes don’t act alone. Some are primary fluxes (like sodium and potassium), eager and strong, melting early at lower temps. Others are secondary fluxes (like calcium or magnesium), slower to act, needing the company of strong fluxes before they step in. Get the proportions wrong and you’ve got trouble:

Too much flux → runny, crazed surfaces.
Too little flux → stiff, underfired, chalky glazes.
Balanced flux → a stable melt, glossy or matte depending on the mix, with just enough strength to fuse clay and glass.

It’s the same dance in the human body. Electrolytes—ions like sodium, potassium, calcium—keep your nerves firing, muscles contracting, and fluids balanced. But imbalance cuts both ways:

Too much sodium → hypertension, swelling, risk of stroke.
Too little potassium → irregular heartbeat, muscle weakness.
Balanced electrolytes → a body that functions, hidden harmony in constant motion.

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Footnotes / References