Needless to say this is dangerous and DO NOT try this without the supervision of a professional.  To make a vortex at home here is some more info from a DIY article:

The basic steps to creating a vortex cannon are: cut a circular hole in an otherwise sealed cardboard box, fill said box with smoke followed by simultaneously hitting both sides of the box. Due to the opening being circular as well as narrower than the box itself and it being the smokes only form of escape, so when the box is hit the smoke inside is forced out through the opening… creating a vortex,

Commenter C J had this to say about the process of making one:

What actually happens is that the flame ignites the nozzle causing the amount exiting to spike followed by raid decompression and then implosion fuel air mixture and then an explosion. Its far from “the flame following it back up into the can” yes that ultimately happens and it does explode but it doesn’t just ride the gas back up into the can in one smooth motion like people think.

We hope you liked this video and stay interested in the coolness that is science!

thanks to geek.com for the great info