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A shipment EP Kaolin has arrived for use in some of our production porcelain and stoneware bodies. Of course, this needs to be tested before being put into product. But how? The first step is to create a new recipe record in my Insight-Live account, and find their production date code stamp on the bag. Hmmm. It does not have one! OK, then I need to record the date on which we received it. We need to save a bag on every pallet and sieve 50 grams through 100 mesh (to spot contamination). Then we'll make test bars (of all the samples mixed) to fire across a range of temperatures (to compare fired maturity with past shipments). We do a drying performance disk also to assess soluble salts.

This picture has its own page with more detail, click here to see it.
These are SHAB test bars prepared from two different shipments of the same commercial kaolin (EPK is commonly used in porcelain body production). They have just been rolled and marked. The darker set of bars is markedly more plastic.
This underscores the need for body manufacturers to characterize the materials they use in production and maintain an ongoing testing program. This difference flagged an adjustment to the production recipes: A reduction in the percentage of bentonite in the bodies.
| Projects |
Testing a New Load of EP Kaolin
Kaolins can vary in many ways. Yet they are the foundation of all porcelain and light stoneware clay body recipes. It is vital to test each incoming shipment of material. Problematic brands can even require some testing on every pallet. |
| Materials |
Kaolin
The purest of all clays in nature. Kaolins are used in porcelains and stonewares to impart whiteness, in glazes to supply Al2O3 and to suspend slurries. |
| Articles |
Setting up a Clay Testing Program in Your Company or Studio
Set up a routine testing pipeline and start generating historical data that will enable your staff to understand your source materials and maintain, adjust and troubleshoot your clay body recipes. |
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