a propane torch with auto ignition will work just dandy. However, I start with about 50 pounds of pressure. As you hear the metal, the air gets hot, expands, and builds pressure, so starting with more pressure and using propan will work. Also, with propane, you have less chance of getting a hole in your pipe, as it's tougher to liquify the metal.
I've blown plugs out the end, and you DON'T want to get hit with that missle. Make sure the ends are pointed towards the wall, and you wear safety glasses!!!! It's tough to ride with only one good eye.
Rick