We use it to attach hairpieces and wigs in the Theater. It works pretty well, although I have never used it on my regular hairpiece. It is pretty undetectable at the front hairline. It is best if you use the sweat proof kind.
One funny story-I was doing a show with a guy who liked to drink quite a bit. He was the type of guy that you could smell the alcohol coming out of him when he sweated. Well, after about a month of the run, the wig people were going out of their minds trying to figure out why they couldn't get the spirit gum to sork on his wig! Well, they finally put 2 and 2 together and realized that the alcohol in his sweat was causing the spirit gum to come loose!
-ANDREW (NEVER ANDY