|Monthly Tech-Tip |
This is G2934Y white (with 10% Zircopax). I initially blamed the zircon for the crawling. But, since the slurry had settled somewhat I was able to remove about 15% of the water and replace it with CMC gum solution. The gum addition was not enough to slow down the drying much (one reason to avoid gum if possible). That fixed it! Meaning that adherence of the dried layer to the smooth bisque was the issue. This being said, there were still a couple of small spots where it crawled. Replacing another 5% of the water should fix that. If you need to fix the problem with a gloss white it will likely require less gum, start with replacing 10% of the water.
CMC gum is indispensable for many types of ceramic glazes. It is a glue and is mainly used to slow drying and improve adhesion and dry hardness.
A ceramic glaze fault that occurs during firing of the ware, the molten glaze pulls itself into islands leaving bare patches of body between.