My wife bought a bottle of hand sanitizer to keep in her truck. She likes to keep it in her cup holder so it is at hand when needed, but because the bottle is so narrow it tends to flop around when she is driving. She found this slightly annoying and asked me to come up with a way to fix this. Originally I had thought we could simply get a large spring and place it between the edge of the cup holder and the bottle to keep it in place. But my wife was confident she would lose the spring. She wanted some sort of insert that would stabilize the bottle and yet could be easily removed if a beverage ever needed to reside there. I combined these two ideas for the following solution.
Step 1: Materials and Tools
To make this project I used the following materials and tools:
1 large water bottle
5 compression springs (heretofore know as "the springs")
E-6000 (or your favorite adhesive)
Step 2: Bottle Cutting
I used an old water bottle that was taking up space in the cupboard as the basis for the project. I wanted a large bottle that would nearly fill the cup holder so there would be adequate space to accept a variety of bottles. To determine where I needed to cut the bottle I placed it in the cup holder and noted where it was even with the top of the holder (not pictured). I then used a hacksaw to cut the bottom off the bottle. With the rough cut made I used a utility knife to cut the large burrs off the rough cut. Finally I used a butane torch to smooth out the edge.
Step 3: Add the Springs
I wanted the springs to come close to touching but still have space in the center to allow movement. Ideally they would all be the same size and tension. Unfortunately since I work from salvage I used five that were pretty close in length. I dry fit the end coils of the springs over the edge of the insert and played around with the configuration until I was satisfied with spacing. With that done I applied E-6000 to the end coils of the springs and the edge of the insert then fitted the springs back into place. I used scrap plastic to spread the E-6000 evenly over the ends of the springs to ensure maximum hold. Then I allowed it to dry.
Step 4: Installation
When the E-6000 had fully cured I put it in the cup holder like I would a water bottle. I then pushed the hand sanitizer bottle down into the center of the springs. This was a little trickier that I anticipated but I was able to "persuade" it into place with a minimal distortion of the insert. The second picture shows this distortion and the springs nestled tightly about the bottle.