This Instructable will show you how to build a cheap air ram for holiday props, robotics or whatever else you want to do with em! You could just go out and get a screen door closer, but for the price of two and a few extra steps, you can make around 10 of them a foot long ! If needed, you can change the length of the cylinder as well as the diameter of the pipe used. Here I am using 1/2“ pvc. If you want to use larger pipe, you will have to do some trial fitting at the hardware store for a piston and seal. Let’s get to it!