I had used tennis balls because I am an avid club player and had extra cardboard laying around, and I even had my homework done so I started looking around the house for ideas to combine the two materials and to use my free time. This project came about because the baseboards were having a rough time keeping the doorstop screwed in and they would fall out over time which meant several holes were drilled and I had to keep covering up the old ones. So I'm trying to avoid the problem by recycling my tennis balls and have a creative twist for doing chores.
Step 1: Cut the Tennis Ball in Half
Using a pocket knife, I cut the tennis ball in half. Don't worry about going straight down the middle because you can just use the two bigger halves of two different balls like I did.
Step 2: Make the Center
To make the width of the doorstop be large enough to actually be useful, I had to put three pieces of cardboard in the center by using hot glue. This was to stop the handle of the door from going through the wall.
Step 3: Add the Tennis Balls
Put a ring of hot glue around the circumference of the tennis ball and press it firmly to the cardboard. I used 2 of the bigger halves out of the 10 or so that I had. This doesn't mark the door or the wall when you use it and you won't have to worry about it coming loose from the baseboards like the ones that screw in. Just put it in the right place and enjoy!