Craquelure Glaze

Craquelure in glazes is often a desired effect and is usually called “crackle”. It is mainly caused by the different shrinkage rates between the glaze and the clay during the firing process and results in a minute network of cracks in the glaze surface. It is distinguished from crazing, which is accidental craquelure resulting in a glaze defect, although in some cases, experts have difficulty in deciding whether milder crackle effects are deliberate or not.

After firing, to accentuate the crackle, wipe an acrylic or ink over the pot, allowing the ink to fill and highlight the cracks, and then wipe off the excess. The crackle may take some time to appear after the firing process. So don’t fret if it isn’t apparent straight after firing.

A type of double crackle, known as "gold thread and iron wire", (see picture) is where there are two patterns, one with a wide and large crackle and the other with a finer network. This is created by multiple layers of glaze being applied. The wider crackle develops first, with the finer one developing inside those larger sections.

The club doesn’t have a crackle glaze as part of its glaze library, however crackle glazes can be readily purchased at your local pottery store.