Glass Painting

Ok, I am hoping someone here will know what I am talking about, my dad used to do this and I only remember the folllwing: Don't know the name of techinque or anything.

Paint w/Spray paint a clean sheet of glass black
would trace over with letters in reverse
Took razer and scratched out the letters
then would srpay paint another layer on top, when you looked at the side down it would say The Lords Prayer.

I want to try a small scale of this with my youth group, however I don't know the technique or what supplies she sued, dont' remember if he sealed it or what. Please help.