Fixing Pinholes After Glazing: A Potter’s Guide
If you’ve ever opened the kiln, held your finished piece up to the light… and spotted tiny little holes in the glaze, you’re not alone.
Pinholes are one of the most common (and frustrating) glaze issues for beginner potters. The good news? In many cases, they’re fixable, and even better, they’re a great opportunity to level up your skills. Whether you’re just starting out or ready to refine your process, here’s how to fix pinholes, and prevent them next time.
First: What Are Pinholes?
Pinholes are tiny holes in the surface of your glaze, caused by gases escaping during firing. As your clay heats up, it releases moisture and organic material. If the glaze melts before those gases finish escaping, they push through the surface and leave small holes behind.
Totally normal. Usually fixable.
Can You Fix Them?
Yes, especially if they’re small and shallow.
Sanding, reglazing, and refiring is a standard studio fix and works well in most beginner situations. In our experience, this method works when the issue is surface-level.
How to Fix Pinholes (Step-by-Step)
1. Lightly sand the surface
Use fine grit sandpaper (220–400). Focus on smoothing the glaze and opening up the pinholes slightly.
Beginner tip: Go slow—you’re not trying to remove the glaze.
Intermediate tip: If you start to see clay body peeking through, stop. That area may need a slightly thicker reglaze to even out absorption.
2. Clean your piece thoroughly
Rinse and wipe with a damp sponge. Let dry completely.
Beginner tip: Dust left behind = more defects.
Intermediate tip: After drying, run your hand across the surface. If it feels chalky, rinse again—fine particles can linger and cause crawling on refire.
3. Fill before you coat (optional but powerful)
Rub a small amount of glaze into the pinholes with your finger, then wipe the surface clean.
Beginner tip: This step is optional but helpful.
Intermediate tip: Use a slightly thicker glaze slurry for this step, it fills holes more effectively than a thin coat.
4. Apply a thin coat of glaze
Brush or dip a light, even layer over the area.
Beginner tip: Thin is better than thick.
Intermediate tip: If your glaze tends to pinhole, try slightly thinning it with water before applying. A more fluid melt can help gases escape more cleanly.
5. Refire the piece
Fire to the same temperature as before.
Beginner tip: Treat it like a normal glaze firing.
Intermediate tip: If you have a kiln, add:
- A slower ramp between 1000°F–1600°F (where burnoff happens)
- A 5–10 minute hold at peak temperature
This gives gases more time to escape and the glaze more time to heal.
When This Fix Works Best
- Small, scattered pinholes
- Smooth glaze surfaces
- Properly bisque-fired work
When Pinholes Keep Coming Back
If you refire and still see pinholes, the issue is usually deeper in the process.
Here’s what to adjust next time:
Glaze Application
- Too thick = traps gases
- Aim for even, moderate coats
Drying
- Handbuilt work needs slow, even drying
- Trapped moisture = more gas during firing
Clay Handling
- Compress slabs and joins well
- Air pockets and uneven density can contribute to defects
Bisque Firing
- Under-fired bisque can leave more burn-off for the glaze firing
- A slightly hotter or slower bisque can help
A Note for Handbuilders
Handbuilt pottery has more variation in thickness and density than wheel-thrown work. That’s part of its beauty, but it also means gases don’t always escape evenly.
The more you:
- Compress your clay
- Dry slowly
- Apply glaze evenly
…the fewer pinholes you’ll see over time.
The Bigger Picture
Fixing pinholes isn’t just about saving a piece, it’s about understanding the relationship between clay, glaze, and fire.
Every refire teaches you something:
- How your glaze moves
- How your clay behaves
- How small adjustments make a big difference
At Potterings, we see these “imperfect” moments as part of the craft. They’re not setbacks—they’re progress.
If you’re unsure whether a piece is worth refiring, bring it into the studio. We’re always happy to take a look and help you troubleshoot your next step.
Happy making – Potterings.