and applied to test sheets under the same experimental conditions and stoved for the same lengths of time at 770 u00b0 c 785 u00b0 c and 805 u00b0 c the falling apparatus according to dez merkblatt f 6 2 was used for the bonding test the results were assessed visually on the deformed sample bonding stage no 1 being given a value of 100 and bonding stage no 5 given a value of 0 the results of this experimental series are represented in the accompanying diagram as stoving curves a 770 u00b0 c b 785 u00b0 c and c 805 u00b0 c it is clear from this that the best bonding especially in the range of low temperatures of base enamel frits is obtained with the atomic ratio si b na nio 1 1 1 0 06 when there is a deviation from the value na 1 an increase or reduction in the na content in the system si 1 b 1 na 0 6 1 4 ni 0 06 results in a deterioration of the bonding even at elevated stoving temperatures although the flow values of the frits according to din 51 161 increase with increasing na content this is surprising and contradicts the known state of the art which proceeds on the basis that frits with a high b 2 o 3 content promote wetting and soft base enamels bond more firmly than hard base enamels filling base enamels network base enamels.