Where do I findLG LCD ribbon connector tape for Late 2012 iMac?

I'm sure this has happened FAR too many times that someone has pushed a razor just a little too far into the adhesive tape around an iMac screen and punctured the ribbon tape that carries the signals from the controller board to the LCD screen itself.

Where do I get more of these ribbon tapes and how do I use heat properly to remove the severed ribbons and then install the replacement ribbons?