Glaze Testing Like a Pro: How to Actually Learn From Your Test Tiles
You're making test tiles, but are you learning from them? This guide shows you how to run systematic tests and build a glaze library you can reference years later.
⚠️ Confession time: How many test tiles have you made that you can't identify six months later? Let's fix that.
Why Most Glaze Tests Fail
You make the tiles. You fire them. They come out beautiful (or disasters). And then... what?
Six months later, you find a stunning test tile and have absolutely no idea:
- What glaze that was
- What clay body you used
- What cone you fired to
- Whether it was dipped, brushed, or sprayed
- If there was an underglaze or oxide wash underneath
The result? You can't reproduce it. All that testing was wasted.
The System That Actually Works
1. Standardize Your Test Tile Format
Make all your test tiles the same size and shape. Seriously. A 3"×4" flat tile with a curved section works great — it shows you how the glaze breaks over texture and pools in recesses.
Stamp or carve into the wet clay:
- Glaze name or code ("AM-23" or "Coyote Shino")
- Clay body code ("B-Mix" or "^6 Speckled")
- Application method ("3 coats dip" or "2 brush")
- Date
🎯 Smart potters use The Potter's Mud Room to photograph every test tile and log the exact details: clay body, glaze recipe or commercial name, firing schedule, cone, atmosphere, and notes. When you find a winner two years later, you'll know exactly how to recreate it. Track your tests free →
2. Test One Variable at a Time
This is Science 101, but potters forget it constantly.
Bad test: "I tried Glaze A over Glaze B on a new clay at a different cone."
Good test: "I tried Glaze A at three different thicknesses on Standard 266 at Cone 6."
When you change multiple variables, you can't isolate what caused the result. Pick one thing to test:
- Thickness (1 coat vs 2 vs 3)
- Clay body (same glaze on different clays)
- Firing temperature (Cone 5 vs 6 vs 7)
- Layering order (Glaze A over B vs B over A)
- Application method (dip vs brush vs spray)
3. Fire Test Tiles With Real Pots
Test tiles in isolation don't tell the whole story. Kiln atmosphere, placement, and neighboring pots all affect results.
Pro move: Fire your test tiles in the same kiln load as the pieces you're glazing. Tape the tile to the shelf edge or stand it against a piece. That way you know: "This is how Glaze X actually fires in my kiln, in my conditions."
Document Everything (Or Regret It Later)
Here's the hard truth: your memory is not reliable. Three firings from now, you won't remember which cone you fired that test to.
What to Log for Every Test Tile:
| Field | Example |
|---|---|
| Clay Body | Laguna B-Mix 5 |
| Glaze Name | Amaco Potter's Choice Textured Turquoise |
| Application | 3 coats, brushed |
| Bisque Cone | 04 |
| Glaze Cone | 6, slow cool |
| Atmosphere | Electric oxidation |
| Photo | ✅ Front + side angle |
| Notes | Slight pinholing on thick areas, beautiful break over texture |
Where to store this? A notebook works. A spreadsheet works. But The Potter's Mud Room is purpose-built for this: upload photos, tag clay + glaze + firing schedule, add notes, and search later by any field. It's designed by potters, for potters.
Stop Losing Your Glaze Tests
The Potter's Mud Room helps intermediate and advanced potters organize test tiles, track glaze combinations, and build a searchable visual library of what actually works in your kiln.
Advanced Tips: Glaze Combination Matrix
Once you have 10–20 glazes you love, test them in combination.
Make a grid tile:
- Divide a flat tile into squares (use wax resist or tape)
- Apply Glaze A on the left half, Glaze B on the right half
- Let them overlap in the middle
- Label and fire
Now you have a visual record of how A+B interact. Repeat with other combinations. This is how pros discover their signature layered looks.
Organize Your Finished Tests
Physical organization matters:
- Binder rings: Drill a hole in each tile, thread them on a binder ring by category (cone, clay body, glaze type)
- Magnetic board: Attach small magnets to the back, display your favorites on a metal sheet in the studio
- Shadow box: Frame your best results as inspiration
Digital organization is just as critical. You need photos + metadata + search. A folder of unlabeled images won't cut it.
💡 Final Thought: Testing without documentation is just expensive guessing. The potters who grow fastest are the ones who learn from every firing — and that only happens when you can look back and see patterns. Join The Potter's Mud Room and start building your glaze library today.