was observed with respect to the non lead frits of table i thus curve 6 based on blend 6 with the fine alumina addition is much steeper than curves 5 and 7 these curves represent blends 5 and 7 which contain the same amount of alumina as blend 6 but having a coarser particle size table ii______________________________________blend 5 6 7______________________________________lead base frit 96 96 96 alumina 0 5 u03bc 0 4 0 alumina 6 8 u03bc 2 0 4 alumina 4 6 u03bc 1 0 0 alumina 10 15 u03bc 1 0 0______________________________________ table iii sets forth in weight percent a further series of sealing glass paste blends in this table blends 8 and 9 contain additions of zirconia while blends 10 and 11 contain comparable additions of alumina the frit employed had the tin zinc phosphate composition shown in blend 1 of table i table iii______________________________________blend 8 9 10 11______________________________________frit 70 70 70 70 beta eucryptite 10 10 10 10 zircon 15 15 15 15 zirconia 0 5 u03bc 5 0 0 0 zirconia 6 8 u03bc 0 5 0 0 alumina 0 5 u03bc 0 0 5 0 alumina 6 8 u03bc 0 0 0 5______________________________________ it will be observed that blends 8 and 10 contain very fine particle size 0 5 u03bc zirconia and alumina respectively likewise blends 9 and 11 contain larger particle size 6 8 u03bc zirconia and alumina respectively these blends were.