How to Mix Small-Batch Test Glazes Without Wasting Materials
Glaze recipes are fickle. They lie to you. A formula that works for one potter might crawl, pit, or turn to ugly mud on your specific clay body. So you test. Or at least, you should. But mixing up a full 5,000-gram bucket of some Pinterest glaze just to watch it shiver off your mugs in the kiln? That's not testing. That's just expensive heartbreak. For anyone running a home studio pottery setup, learning how to mix small-batch glaze samples is the single best way to save cash and keep your sanity intact. You don't need a chemistry degree. You just need a gram scale, some discipline, and the ability to resist the urge to mix giant buckets "just in case."
The Math Is Annoying. Do It Anyway.
Here's the thing about test glazes : the batch size matters. Most glaze recipes are written for 100 parts. Don't just wing it and scoop with a teaspoon. Get a cheap digital scale that reads to 0.1 grams. Divide everything by ten. Mix 100-gram batches. That's ten grams of silica, ten grams of feldspar, whatever. It sounds tiny. It is tiny. But it's enough to dip one test tile and one small cup. You get your answer. You see the color, the texture, the fit. And if it's garbage? You dump ten grams of failure into the trash instead of fifty bucks worth of raw materials. I keep a spreadsheet on my phone. Old school potters used index cards. Either works. Just don't trust your memory. Your memory is terrible after a long day in the studio.
Get a Dedicated Test Toolkit
Cross-contamination is the silent killer of small-batch glaze testing. You measure out ten grams of cobalt, then use the same spoon for your rutile. Congrats, you just invented a weird blue-brown that doesn't exist in nature, and you'll never be able to replicate it. Keep a separate set of tiny tools. I'm talking about a one-dollar set of measuring spoons from the thrift store, a few plastic cups you never use for food, and a whisk you stole from the kitchen and immediately regretted. Label them. Treat them like lab equipment, because for the next twenty minutes, they are. And never, ever mix your test glazes in your main glaze buckets. That's how you ruin a whole batch of perfectly good white satin with a rogue speck of copper oxide.
Write It Down. No, Really. Write It Down.
The number of brilliant glaze combinations that have been lost to the universe because someone said "I'll remember this" and then absolutely did not remember it is staggering. When you mix glaze cheaply in small tests, the only thing more valuable than the materials is the information. Every single time you mix a test, write down the exact recipe, the date, the clay body, the firing schedule, and where you put the damn test tile. I number my tiles with a sharpie on the back and keep a matching logbook. Sounds uptight. It's not. It's survival. Because three months later, when that one accidental test comes out of the kiln looking like liquid moonlight, you need to know exactly how you got there. Otherwise, you're just staring at a beautiful mystery you'll never solve.
Test Smart, Not Hard
You don't need to fire a hundred full-sized pots to test a glaze. Make yourself a stockpile of standardized test tiles. Same clay, same thickness, same shape. Bisque them all together. Then when you're ready to mix glaze cheaply and run some trials, you have a consistent surface to work with. Dip half the tile, pour the glaze, double-dip it, brush it on thick. One tile can give you four data points. I also keep a set of small thrown cylinders, like tiny cups, because a flat tile doesn't always tell you the whole story. Glazes act weird on rims. They run on vertical surfaces. They pool in feet. If you only test flat, you're flying blind on the geometry that actually matters for your pots.
Stick Them Wherever They Fit
Firing a whole kiln load just for tests is a waste of electricity and time. The real hack for home studio pottery ? Shove your little tests into the nooks and crannies of your regular firings. Got a half-inch gap between two bowls on the shelf? That's prime real estate for a test tile. Sneak a tiny cup behind a large vase. Fill the negative space. Your test glazes don't care if they're surrounded by other pots. They just need to reach temperature. This approach costs you literally nothing extra in terms of firing costs. Plus, you get to see how your test behaves in the actual thermal environment of your real work, not some perfect, isolated lab scenario. And keep a sharpie in your apron. You'll need it.