This instructable will show you how to make your own medicine ball, for use with all different kinds of exercises, for a fraction of the cost of purchasing one!

Step 1: Get a Basketball!

I bought my basketball from Wal-mart for $6, so you can definitely find one for under $10.
To fill the basketball, you have a few choices:

1.) I cut two slits in the ball, making a triangular flap.
I then taped the flap back, and filled my ball with sand.
Closing a flap is a little messy, but I had intended on taping the ball anyway, so it made my filling quicker.

2.) You could use an awl or a drill to put a hole in one of the black stripes on the ball.
Fill the ball with a small funnel, and then patch with a radial tire patch kit.

Step 2: Fill the Ball

-If you fill using my method, you can use a dowel or a broom handle or something to occasionally pack down the contents as you fill it.
-If you fill using the small hole/funnel method, I think the only thing that you can do to pack down the contents is occasionally shake the ball to make sure that everything settles.

To fill the ball, I used an empty drink pitcher to pour sand through the opening cut in the ball.

Using a bag of play sand purchased from Home Depot ($4), the ball ended up at just below 25 lbs.

Dry sand has a density of around 1600 kilogram/cubic meter
Wet packed sand around 2000 kg/cu.m.
Some lighter household materials that would work for this instructable are:
Coarse salt is around 800 kg/cu.m.
Fine salt is around 1200 kg/cu.m.
Granulated sugar is around 850 cu.m.

Or improvise for your contents!
Just remember, sand makes a pretty heavy medicine ball by itself!

Step 3: Last Preparations & Closing the Ball

After your basketball is filled, make sure it's really packed so that the contents don't settle much once it's sealed.
If using a funnel, tap the ball on a table or floor and attempt to fill more.
If you cut a hole in the ball, you can just compress the contents with your thumbs through the opening.

Make sure that there are no soft spots around the outside of the ball, as these indicate air pockets.
Just push your thumbs around the sides of the soft spot until it fills in,
then settle the contents of your ball and add more if possible.

If you used the funnel method, congratulations! You have much more patience than I do!
And you don't have to wrap your ball in anything to keep it stable or give it grip.
You can fill the hole by following the directions on the back of the radial tire patch kit I had suggested earlier. I haven't actually done this method of sealing, so I'll leave the instructions up to the packaging.

If you used my method, now it's time to seal back the flap on the ball. I glued the flap down with Gorilla Glue, but the glue was probably unnecessary due to the possibly excessive amount of duct tape that I covered the ball with next. I taped three layers of duct tape, gray-black-gray, using the color difference to tell if my taping pattern had indeed covered the ball entirely.

I started at one point on the ball, and taped around the ball, ending at the same spot.
I then taped perpendicular to my first strip of tape in the same fashion, starting from the opposite side of the ball.
Fill in all the surface area using this method, and you're almost guaranteed not to end up with any thick or thin spots of tape on the ball. It should theoretically be rather uniform in shape still.

The taping probably didn't need to be so meticulous, but I go big on details.

Step 4: Add Some Grip, and You're Done!

I found out quickly that duct tape became very slippery after only a few throws,
or a few exercise repetitions.
To solve the problem, I bought a 3 pack of cloth hockey tape from a sporting goods store.
Following the same method of taping that I used with the duct tape in the previous step,
I covered the ball in 3 layers of hockey tape.
The layers go in opposing directions so that even if the tape does start to peel,
only the top layer can peel.
Once you've got your cloth tape on, you're done!

Your very own medicine ball, for a small fraction of the cost of buying one!
The heavier you go with the ball, the more money you essentially saved.
Heavy medicine balls can be upwards of $80 depending on where you buy.
And good luck even finding some of the medicine balls above 12 lbs or so.