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Anyone Tried Additive A


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#21 glazenerd

glazenerd

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Posted 09 January 2017 - 06:22 PM

 

VGT is also great in brushing glaze formulas....................indeed Neil !!  like brushing on thick latex paint.  I like even better for stains; keeps them suspended-dispersed.

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#22 glazenerd

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Posted 11 March 2017 - 10:45 AM

Okay Doc:  after much study and research: I will answer your question. 

 

Additive A is an ionic polymer that creates isomorphous substitution, when mixed with a clay body. Additive A would be much more useful in a porcelain body, and have a negative effect in stoneware because ball clay already has a negative ionic polarity. Kaolin is unable to absorb water into its platelet: while ball clay/s will. Secondly, kaolin has a neutral charge on the surface of its platelet, and ball clay has a negative charge. Because kaolin cannot draw water on a molecular level (except halloysite), a negative platelet charge can only be produced by isomorphous substitution.

 

Isomorphous substitution is defined (in clay chemistry) as using chemical manipulation/substitution of negatively charged molecules, to "substitute" positively charged ions. VeeGum T works on the same principle, although it is produced from refined naturally occurring smectite/s. Additive A is a synthetic polymer that accomplished the same goal: in that it changes the positive/neutral charge on the surface of the clay platelet to a negative charge. A negative charge (see CEC "cation exchange capabilities) is solely responsible for creating plasticity in a clay body. When clay particles are negatively charged: they repel each other: causing the effect of plasticity. When clay particles are positively charged they attract each other: causing the effect of memory in clay.

 

For this and other useless information you can contact me via email.

 

Nerd

 

Edit note: the percentages of metal oxides in clay effect the final particle charge. Alumina, iron, and magnesium cause differentials in particle charges because of their metallic ions. Kaolin has much higher percentages of alumina: which is the primarily reason kaolin have a neutral particle charge. Ball clay has much less, so the interlayers of its structure hold a negative charge,






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