[Clayart] Hal's Satin Matt

[L TURNER]

Thanks, Robert.

Since I play in several different 'sand boxes' (pure chemistry,
engineering, igneous petrology, …) clarity of correlation ratios is a must.

Lou

On Tue, Jun 5, 2018 at 5:57 AM, Robert Harris <robertgharris at gmail.com>
wrote:

> ​​​​​
> Good point. Just shows how lazy I am these days!
>
> I use Insight, which reports the "Si:Al" ratio, but it is in fact reporting
> the SiO2 to Al2O3 ratio, which of course actually has twice as many
> Aluminium atoms as Silicon atoms.
>
> https://digitalfire.com/4sight/glossary/glossary_sial_ratio.html
>
> Also with reference to the original question on underfired mattes versus
> true, recrystallized alumina mattes, this old chart by Stull (which I
> mention every so often) is really extremely useful.
>
> https://digitalfire.com/4sight/glossary/glossary_stull_chart.html
>
> (click on it to make it larger).
>
> Note that as you go up the vertical axis (Al amount) at around 3.0 Si, it
> shows the glaze going from devitrified to bright to semi-matte to matte to
> unfused. While shinos are an example of fused alumina mattes, at the other
> end, Nuka is an example of a devitrified high silica low alumina glaze.
> (The devitrification is what turns it white.)
>
>
> Robert
>
> On Sun, Jun 3, 2018 at 9:33 AM, L TURNER <magnolia.mud.list at gmail.com>
> wrote:
>
> > On Sun, Jun 3, 2018 at 4:02 AM, Robert Harris <robertgharris at gmail.com>
> > wrote:
> > "... If you look at the recipes the Si:Al ratios are in the region of 5:1
> > (say 3.25:0.65 or even 0.7)".
> >
> >
> > Robert,
> >
> > In the interest of clarity:
> > When you use  the term "Si:Al ratio" do you mean the ratio of the number
> of
> > silicon and aluminum atoms rather than the molar ratio of amounts of
> silica
> > (SiO2) and alumina (Al2O3)?
> >
> > LT
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