Yea, you have to have a special stuff for that thing. The defroster lines are more of a electric conductive paint.
I worked at a glass place back in the day that made the rear windows for the Hummer 1, and we had hell doing the windows. After laying the defroster lines(paint), we had to do a continuity check(superivised by the shift supervisor), if it didnt check out, the window went thru again and if it failed the second time, window was trashed. We basically had a 30-40 percent fail(trashed) glass.
With the new technology it may be easier to fix the window defroster.
sig pic courtesy of GBALT05