I repaired a split defroster wire on my ‘94 coupe I had with a “defroster repair kit” that I purchased over the counter in the parts department at my local Chevy dealer. It was similar to the Frost Fighter. Took several minutes to do, just let it cure and your grid will be back in business.
I fixed my defroster by using a conductive epoxy by "Circuitworks". You can get this at any electronic store or check their website: www.chemtronics.com. Use it like epoxy, by mixing the two parts together, a conductive part and hardening agent. Had it on for over a year and is still holding together.