This how to video shows you how to build a marshmallow cannon. You will need piping, marshmallows, stiff paper, a grill igniter, hairspray, and an elbow piece. First, assemble the piping together with the elbow so that it creates an L shape. Next, place the igniter at the bottom of the pipe. To load the marshmallow, wrap a piece in paper. Next, shove it into the barrel. Spray some hairspray in the pipe where the igniter will be. Re-assemble the pipes and then place the igniter in and light it. You will get an average of 71 feet. Too much hair spray will be harder to use and you will get less distance.