Have you ever needed something a little stronger than your run-of-the-mill rubber band? Do you have about 30 minutes and a punctured bicycle inner tube laying around? If so, this little 'ible will help you make some truly cool rubber bands and a convenient way to store them. You may also build a little finger strength in the process. :)

Credit where it's due: This 'ible builds on the work of dent244's "Ranger Bands" and is similar to zjharva's "Inner Tube Ball".

Let's get started!

Step 1: Gather Your Resources

For this project you will need:

A bicycle inner tube
A cutting board
A curved blade
A gallon-sized plastic bag
A kitchen sink with soap
A towel or two

The inner tube can be from just about any bicycle, although the larger the wheel, the easier it will be to cut the bands into parallel lines. Avoid using puncture resistant tubes, since they have uneven wall thicknesses (although that could be to your advantage depending on the application).

Other projects use scissors to cut the bands. I have had mixed results with the band shape and quality when using scissors, and it can be hard to cut some of the thicker inner tubes with scissors.

Step 2: Cutting the Bands

Here is the secret sauce for this project: Use a curved blade and cutting board.

Cut the section of the tube containing the valve stem out of the tube. You can discard this piece.
Lay a length of tube on the cutting board.
Cut the tube into bands using a rolling motion and firm pressure on the blade
1. For this project, keep the bands between 1/8in and 3/4in wide (5mm-20mm).
2. Note that the blade may not fully cut the back side of the tube.That's okay - the bands can be pulled apart after you're done cutting.
3. Avoid rocking the blade back and forth -- that will create hairline cuts.

Step 3: Quality Control

Check your bands as you cut. Sometimes there will be one that is just a bit too thick. When that happens, just cut it down the middle.

Step 4: De-gunkification

By now you should have a few chalky, perhaps dirty black rubber bands on your counter. Before we can roll them into balls, they need to be washed.

Gather them into a plastic bag
Add 1 drop of dishsoap and some water
Lather, rinse & repeat as needed
Dry the bands on your towel(s)

You may need more or less soap depending on how dirty your bands are, but for a generally-clean inner tube, it should only take one washing to get the whole tube's worth clean.

I have tried washing the tube before the cutting process, and it was a mess. So even if it gets your cutting board and knife dirty, it's still easier to wash after cutting.

Step 5: Roll Out!: Forming the Core

Did I mention these balls were hard core (rubber)?

Start by taking a wide band and rolling it into a tight cylinder, like a rolled rug.
Using a second wide band to hold the first, roll an even larger cylinder.
Wind a thinner band (#3) around bands #1 and #2 by adding a twist and doubling up the band.
Keep adding thinner bands until the core is big enough to just barely stretch the wider bands again.
Add 3 wide bands in mutually perpendicular orientations
1. Think "Equator, Prime Meridian/International Date line, 90°E/W Longitude"

Step 6: Finish Him!!

Now that the core is formed, add more rubber bands!

You'll know your band ball is fully grown when there just isn't enough stretch to place another band.

Step 7: End Notes

For this project I used 26 x 1.5-2.0 standard wall inner tubes. One 26x1.5-2.0 tube will make two (2) rubber band balls. Other tube sizes will likely yield different results.
Older tubes may develop a skin that rubs off due to ageing of the rubber. This is normal and will not affect the rubber band performance, but may not look so good. See previous photos for comparison of a newer tube vs. older tubes.
These balls are okay for throwing and catching, but they don't bounce very well. You could probably use them for baseball or stickball, but I wouldn't recommend it since you'll knock a few bands off every time you hit it.
Please do not throw them at any people or animals. You have been warned.