|Monthly Tech-Tip |
Both the fritware body and glaze contain significant percentages of New Zealand kaolin (NZK). White agglomerates of it have ruined both. The body was slurried by propeller mixing (at the highest speed) and dewatering on plaster. The glaze was slurried and propeller-mixed in a similar manner. But in both cases, the action of our lab mixer, a very capable device, was not enough to break up the kaolin agglomerates! This relates to the stickiness and particle dynamics of NZK. The glaze is the easiest to fix: Sieving at 100 mesh. But the body is just about impossible to sieve because it contains significant VeeGum which gels the slurry. But since I make smaller quantities of both of these, as a potter, blender mixing is much easier, it totally smashes them. However caution is required, the slurry needs a high enough specific gravity that it circulates freely in the blender jar. But a low enough one to enable the maximum RPM of the blender.
The fine mineral, oxide and clay particles used in ceramics often aglommerate during storage or even in the latter stages of production. These must be broken down later.
New Zealand Halloysite
The whitest burning kaolin we have ever seen. It is very sticky when wet, suspends glazes well & makes super white porcelain (with help from a white bentonite).