You might consider this stuff from Amazon...
1 x 2g ELECTRO-CONDUCTIVE ADHESIVE GLUE FOR REPAIR
HEATING CIRCUITS, PRINTED CIRCUIT BOARDS etc - HIGH QUALITY PRODUCT
Excellent silver-based adhesive, electrically conductive.
Indispensable to repair broken windshields heating circuits.
Resistant to changing weather conditions (rain, snow, frost).
Good luck...
Bernard Manning, September 2014