Vinyl plastic folders are great for this project because they are inexpensive and extremely durable. Unlike paper, these pinwheels will be weatherproof so they can stay in your backyard all summer long. Trim the plastic folders by using a utility blade to detach the pockets and gussets. You will be able to make two pinwheels out of each folder, using the front and back panels.
Use a ruler as a straight edge to cut diagonally from all four corners of the square, towards the center. Do not slice all of the way across, leave 1” of vinyl uncut in the center so that you have four triangular pinwheel blades. The easiest way to do this is to measure the diagonal (13”), divide that number in half (6-1/2”) and then take an additional 1/2” off so that each cut measures 6” from corner towards center.
Assembling the pinwheel begins by creating holes which the nail will fit through. The nail should fit loosely through the holes in the vinyl, to allow for minimum resistance. Punch the same corner on each triangular pinwheel blade so that there are four holes, and also punch a hole directly in the center of the square.
The pinwheel takes shape as you gather all four hole-punched corners together in the center. Thread the nail through the four blades from the front, back towards the hole in the center of the vinyl. Slip a washer loosely on the backside of the pinwheel over the nail. The washer will help minimize friction and resistance between the vinyl and the wooden dowel.