"Roger Shoaf" wrote in message
...

Perhaps you can thread some dental floss or thin piano wire between the
joint and cut through the tape. Some heat from a heat gun might help
also.

Try the dental floss first as it is less likely to scratch the coating on
the back of the mirror.

Spectra fishing line is considerably stronger than steel (or dental floss)
of same diameter.
http://users.acsol.net/~wfi/fish-tuf.html