If you’ve ever opened the kiln to find your beautiful bowl permanently fused to the shelf, or you’ve received a piece of pottery back from your community studio with kiln wash stuck to the bottom (or worse!), welcome to the club. One of the most common beginner (and experienced potter) mishaps is pottery sticking to the kiln shelf. The good news? It’s preventable.
Here’s what you need to know to keep your pieces—and kiln shelves—safe.
1. Always Use Kiln Wash
Kiln wash is your first line of defense. It’s a protective barrier that keeps glaze from bonding your piece to the shelf. Think of it like a non-stick coating for your oven racks.
- We apply kiln wash to all our shelves ourselves (so you don’t have to), but understanding why it’s important helps you make smarter firing decisions.
- If you’re firing at home, mix and apply the kiln wash as recommended. Let it dry fully and recoat after each few firings, or touch up any bare spots.
2. Mind Your Glaze Application
Glaze Run-Off (Especially Common with Mid-Fire Glazes): This is the most common reason. Mid-fire glazes, when applied too thickly or too close to the foot of your piece, can become quite fluid during the cone 5 or 6 firing. If it drips or flows onto the kiln shelf, it acts like a glass adhesive once it cools and solidifies. Some mid-fire glazes are notoriously runny, so extra caution is needed.
- Wiping the bottom: Always sponge off the bottom ¼ inch of your piece after glazing.
- Use a resist: Using a wax resist on the bottom will ‘resist’ the glaze; this is especially important with dipping glazes.
- Checking for drips: Before placing your piece on the glaze cart, double-check the bottom edge for thick glaze or runs.
- Understanding your glaze: Some glazes are more likely to run at mid-fire temps. At our studio, we label “runner” glazes and provide glaze test tiles to guide you.
3. Use Stilts or Cookies (if needed)
- Stilts: Stilts can lift your piece off the shelf. Talk to your community pottery studio technician about stilt usage, as there’s usually a method and restriction.
- Cookies: These are small discs of clay (also kiln-washed) that go under your pot to catch any possible glaze drips. They’re especially helpful for beginners experimenting with new glaze combos.
- Wadding: Small balls of refractory clay can be placed under the foot of a piece to lift it slightly, similar to stilts but often leaving less noticeable marks. This is particularly useful for certain firing techniques at mid-fire.
4. Know Your Clay & Glaze Compatibility
Some clay bodies and glazes melt more than expected at cone 6. If you’re using a new combo, ask your instructor or refer to the glaze chart. At Potterings, we help you choose combos that are stable at mid-fire temperatures. While we all love a good, luscious glaze, over-applying can lead to problems, especially with the increased fluidity of mid-fire glazes. Pay attention to how thick you’re applying your glazes, especially near the base. A thinner, even coat is always better than a thick, gloppy one that’s prone to running. An exception is a ‘flux’ glaze, usually, you add a thick coat, but only to the top of your piece (1/3 down or less). Always test new glaze and clay combinations to see how they behave at cone 5 or 6.
5. Don’t Over-Fire
Accidental over-firing can cause even a stable glaze to run. Double-check kiln settings if you’re firing on your own, and always know your clay and glaze’s safe cone range. Mid-fire usually means cone 5 or cone 6—not higher.
Final Thoughts
Preventing pottery from sticking to kiln shelves is a cornerstone of successful firing, especially when working with mid-fire clays and glazes at cone 5 and 6. By consistently wiping your glazed feet and employing stilts or wadding when necessary, you’ll save yourself a lot of heartache and ensure your beautiful creations emerge from the kiln ready for their moment in the spotlight. At Potterings, we fire your pieces with care, but we also teach you how to be a responsible and informed potter. That way, your bowls make it to the table—and not the trash bin.
Want more firing tips or hands-on help with glazing?
Join our beginner handbuilding classes or check out our Potterings blog!