[sdiy] Semi-OT: conductive glue?

[Ingo Debus]

Hi all,

I'm trying to repair a piezo pickup for a violin. For each string, 
there are two small (about 3mm * 3mm) piezo slices between two pieces 
of brass. One brass piece is pressed down by the string while the 
other brass piece is mounted into the bridge. The string itself is the 
ground connection for the piezo pickup.

Normally this combo is fixed together, the brass glued or whatever to 
the piezo, but now one of the "upper" brass pieces (the one the string 
rests on) has come off. Any idea how this was originally fixed, and 
how I can attach it again? It doesn't look like it was soldered. The 
piezo seems not to be solderable.

Since the brass pieces form the two contacts of the pickup, if some 
sort of glue is used, it has to be conductive. Does such a glue exist? 
It doesn't need to conduct very good, because piezos are high 
impedance. I already got that "repair conductive silver" stuff which 
is used to repair broken traces on car rear window heaters, but 
haven't tried yet. It looks and smells like fingernail polish so 
probably it doesn't glue good enough.

Sorry for being OT, this is for a MIDI violin, so at least it's synth 
related.

Ingo