PFrit 2261 PotClays Silica/Alumina ratio: 8.2:1 Equivalent Molecular Weight: 343.688 Molecular Formula of PotClays Frit 2261: PbO 1.000 Al2O3 0.086 SiO2 1.860 Percentage Analysis 32.50 % SiO2 2.55 % Al2O3 64.95 % PbO _____________________ 100 % TOTAL Comments: lead bisilicate frit. From PotClays in England.