How to Get a Crackle Effect on Ceramics Without Raku Firing
You don't need a raku firing to get a beautiful crackle effect. With the right glaze — fired on its own dedicated schedule — and an optional extra step, you can get a network of fine cracks running through the glaze surface in a normal electric kiln, no raku or thermal-shock technique required.
1. Use a crackle glaze — with its own firing schedule
The easiest way to get a reliable crackle effect is to use a glaze made specifically for it, such as AMACO KI-11 Snow Drift Crackle Glaze. Apply 3–4 heavy coats over bisqueware fired to about 1060°C — but note that this glaze does not fire like a normal glaze. It needs its own cone 5–6 crackle-firing schedule:
- Ramp 50°C → 104°C at 83°C/h (approx. 39 min)
- Ramp 104°C → 1082°C at 222°C/h (approx. 4 h 25 min)
- Ramp 1082°C → 1199°C at 56°C/h (approx. 2 h 5 min) – briefly exceeds cone 6
- Drop 1199°C → 1149°C at the kiln's fastest rate, then hold 30 min – this step is what creates the crackle, don't skip it
- Controlled cooling 1149°C → 500°C at 150°C/h (approx. 4 h 20 min) – if your kiln can't program a specific cooling rate, letting it cool naturally on its own from here works fine too
- Free cooling 500°C → room temperature, kiln closed (often overnight)
Total active program time is about 11 h 40 min. Let the pieces sit 1–2 days after firing for the crackle effect to fully develop.
2. Add depth with ceramic ink (optional)
If you want the cracks to stand out more clearly — dark and well-defined instead of faint — you can highlight them with a ceramic ink, for example Botz 9090. Once the piece has been through its glaze firing, sponge the ink over the entire glazed surface so it settles into the cracks, then rinse the piece under water to wash the excess ink off the smooth surface. What's left behind is a dark line running through each crack.
Video tutorial