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Setting Unity
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When Matrix analyses a recipe and calculates a unity formula by default it bases unity on the flux group of oxides. i.e. the values in the flux group of oxides is maniplated to total one and the other values in the formula are recalculated to preserve the correct flux to stabiliser and flux to glass former proportions.

In the Recipe to Formula environment the oxides included in the unity group are indicated by an asterisk next to their chemical symbols. e.g. CaO* or MgO*

Unity Conventions

The convention for a clay recipe is for the Al2O3 oxide value to total one. The formula is calculated to preserve the correct Al2O3 to flux group and the Al2O3 to glass former proportions.

In the case of a glaze the unified flux group allows the comparison of glazes on the basis of the theoretical concept one molecule of flux to X molecules of Al2O3 and Y molecules of SiO2.

Changing Unity

It is sometimes useful to change the unity group e.g. to include B2O3 where you consider this oxide to be acting as a flux in the glaze.

Opening the Set Unity Window

To open the Set Unity Window (Fig.1) select the Set Unity Group item from the Matrix menu.

Fig.1 Preparing to save a recipe to a recipe database

This window has a check box for each of the oxides.

The default setting (all flux group oxides unifired) is reflected in that all of these oxides are ticked.

The colourant oxides are greyed out because Matrix was not set to calculate colourants when the Set Unity window was opened.

To add B2O3 to the unity group:

  • click on the check box next to B2O3 in the oxide list. The effect of this in the formula calculation will be to lower the proportion of Al2O3 and SiO2 to fluxes i.e. the Al2O3 and SiO2 numbers in the formula will go down indicating that you have more flux in the glaze giving a clearer indication of the melting range of the glaze.

Using Unconventional Unity Settings

Unity settings may be useful in comparing glazes from particular perspectives e.g. in a low temperature glaze you may consider that the oxide MgO is so inactive as a flux that it could be removed from the flux group thus giving a truer picture of the potential for the glaze to melt satisfactorily at the low temperature.

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Setting Unity