sealant extends into the recess in the spacer a batch of ten similar units was made up for testing and subject to the weather test as described above ______________________________________no of units having dew pointsno of 49 u00b0 c 39 u00b0 c 29 u00b0 c 19 u00b0 c 9 u00b0 c cy lt 50 u00b0 to to to to tocles c 40 u00b0 c 30 u00b0 c 20 u00b0 c 10 u00b0 c 1 u00b0 c gt 0 u00b0 c ______________________________________59 10110 8 1 1159 6 2 1 1211 5 3 1 1256 5 2 1 1 1309 5 2 1 2357 5 1 1 1 2403 5 1 1 3480 3 2 1 4528 3 1 1 1 4575 1 2 1 6______________________________________ the results show a steady failure of the units on test until after 575 cycles 60 of the units had failed completely this contrasts sharply with example 1 in accordance with invention in which 100 of the units had maintained a dew point below 50 u00b0 c after 1000 cycles the thickness measurements showed the same surprising changes in thickness which were indeed slightly more pronounced as the weathering tests were carried out the procedure of example 1 was reseated using prc trade mark 469 two part polysulphide as secondary sealant in place of the dow corning silicone sealant as in example 1 all 10 units maintained a dew point below 50 u00b0 c for over 700 cycles after 728 cycles one unit was dropped and removed from test after 868 cycles the dew point of one.