Step 1: Step 1: Materials
1. One screw of any sort, as long as it is greater than 2.5" in length
2. One well used sponge, dry as a bone
3. Super Glue
4. Duct tape
5. One 2" scrap of 1/8" plywood
6. Sandpaper of any grit desired
7. Heavy Duty Shears (not pictured)
Step 2: Step 2: Preparing the Sponge
Step 3: Step 3: Create Sponge Ball
With the screw backed out of the sponge disks about .75", apply super glue to the shaft of the screw where it passed through the 1.5" disk, then drive the screw through the sponge before the glue dries. This will carry the superglue into the sponge on the shaft of the screw so the sponge and the screw get well bonded together. This will be important to prevent the screw from spinning inside the sanding ball during use. Add some more super glue to the shaft of the screw where it passes through the 2" sponge disk for additional insurance.
Now super glue the 1" sponge disk over the head of the screw as pictured. Covering this over with the last sponge disk will prevent the head of the screw from wearing through the sandpaper during use.
The final form will look like a stepped sponge cone with a screw sticking out of the back.
Step 4: Step 4: Wrap the Ball in Duct Tape
It took me a couple of layers as the tape had a hard time sticking to the scouring pad part of the sponge.
Step 5: Step 5: Create a Locking Washer
Mark the center of the plywood circle and screw the sanding ball assembly through. Again, a pilot hole may be necessary for a stronger piece of scrap, but I was able to push this through like it was a cracker.
Don't screw the wood circle all the way down onto the sponge ball yet as it will ultimately be used to clamp the sandpaper onto the sanding ball. Leaving 1/8" or so will give some room to slip the sand paper between the sponge ball and the ply wood before clamping it down.
Step 6: Step 6: Prepping the Sandpaper
Mark a circle on the sandpaper about 4" in diameter (I used my duct tape as a template) and cut it out.
Next, fold the circle into eighths and mark these lines with a pencil. Draw a circle in the center of the sandpaper that is about 1" in diameter. Cut the previously drawn lines down to the edge of the 1" circle to create a pinwheel shape. (see images for clarity)
This sandpaper is now ready for action.