SnakeBlack8 made an interesting Instructable called the Potato Gun. I was playing with this idea a few months back during the summer of 2006. Although we were going to make a Spud Launcher we chose to test out the trigger system first. This Instructable is the method to create a piezoelectric trigger for butane.
THIS INSTRUCTABLE IS FOR EDUCATIONAL PURPOSES ONLY. BUTANE IS EXPLOSIVE AND CAN BURN BADLY. DO AT YOUR OWN RISK.
By: Jezza Bear
More: continued here