#BUBBLE CRACKLE GLAZE EFFECT HOW TO#

decrease the content of zinc or rutile in the glaze.add more flux to the glaze to make it more fluid.The following remedies should be tried to cure pinholing or pitting: They can be caused by a badly controlled firing cycle, the glaze composition, or can originate with the body, particularly highly grogged clay bodies. These are the most annoying and difficult glaze defects to cure. Calcining all or part of the zinc can help this problem. Some fluxes, particularly zinc and magnesium, are likely to cause crawling when used in excess. Crawling can also occur when one glaze is applied over another, particularly if the first is allowed to dry out completely before the second application. Crawling is more common in matte glazes than in fluid ones sometimes the problems of crawling can be reduced by the addition of a small amount of extra flux. This can be alleviated by the addition of a small amount of gum to the glaze batch. It occurs where a glaze is excessively powdery and does not fully adhere to the surface of the clay. It is triggered by adhesion problems, often caused by bad application. increase the feldspar, especially sodium feldspar or nepheline syenite, or other alkaline bearing materials.Ĭrawling is caused by a high index of surface tension in the melting glaze.decrease the silica in either the body or the glaze.Shivering is the reverse of crazing, therefore the remedies are the opposite as well: It is the most dangerous of glaze faults. These slivers are usually small, sharp, jagged-edged pieces that detach themselves from the body. Shivering is the most problematic of glaze defects, particularly in any functional ware, since slivers of glaze from the edges can drop into food or drink. decrease any other material containing sodium or potassiumĥ.decrease the feldspar, in body or glaze.In practice, the most effective ways to correct crazing are: In both crazing and shivering the eradication of problems relies on matching the thermal expansion characteristics of both body and glaze. – Jennifer Poellot Harnetty, editorĬrazing is the most common glaze defect, and normally the easiest to correct.

#BUBBLE CRACKLE GLAZE EFFECT HOW TO#

Read on to get some expert pointers on how to solve five of the most common pottery glaze defects (such as crawling, shown at above). So just in case glaze defects are driving you “craze-y” (sorry, I just couldn’t resist), I thought I would share this excerpt from the late Robin Hopper's book, The Ceramic Spectrum. But, of course, there are some cases in which a glaze must be perfect for reasons of safety or hygiene. Many ceramic artists deliberately create faults in their glaze surfaces to achieve a particular aesthetic. It is especially true in the ceramics world that one person’s fault is another person’s fancy–especially when it comes to glaze defects. Pottery Making Illustrated Submission Guidelines.Workhouse Clay International ICAN Merit Award.ICAN Making a Difference in Ceramics Award.Annual National K-12 Ceramic Exhibition Award.

Bubble crackle glaze effect