Calculating Glaze Melting Points

Triggered by this blog post by Daniël Bende: Arriving at Glaze Temperature
The Glasurenspiel software is no longer available as it was for DOS, and the author is dead.
None of these are hugely accurate, but they may be useful for guidance.

Martin Lengersdorff's flussmittelfactor F

First mentioned in his book "Practical Berechnung von Massen und Glasuren", printed in 1964.
A flux factor, F, is applied to each of the oxides, in two groups X and Y, as per the table below:

Al2O3, ZrO20.32
SiO2, TiO20.38


BaO, CoO, CuO, FeO, MnO, NiO, ZnO0.60
K2O, Na2O0.88
B2O3, Sb2O31.00

Using molar representation,
Y = 𝛴(fi.Si) for oxides in table Y
X = 𝛴(fi.Si) for oxides in table X
where fi is the flux factor from the tables, and Si is the quantity. Not sure if the quantity is UMF or molar
F = 100.Y(X+Y)

One source gives firing temperature FT = (161.21789 - F)/0.10252 °C

Another says to use this table, for different glaze types:

Firing temperatureWall tileSanitaryPorcelainMattCrystalline
1000 577082
1020 6880
1040 556677
1060 6475
1080 506272
1100 49.26070
1120 47.85867
1140 5665
1160 46.15462
1180 5260
1230 43 4854
128035.437 4449
130033.835.5 4247

The table above wasn't formatted so I've done my best to put the right numbers into the right columns.




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