Here I will show you how I constructed a heavy medicine ball a few years ago.
Unfortunately I don't have footage of filling the ball but I will guide you through the process.
Mine weights 12 kilograms. If placed in a sturdy plastic bag it can be used also as a kettle-bell.
Step 1: Gather Some Materials
For this instructable you will need :
- an average basketball (approximately 24 cm in diameter)
- epoxy glue
- beach sand
- a funnel
- a hand-drill with appropriate drill bit
- an elastic plumbing flange
- a pin or needle or nail
The ball doesn't have to be anything fancy or expensive. Mine was brought brand new for 2 Euros.
Step 2: Deflate the Ball!
Before you try anything else, first you must safely deflate the ball.
Take the puncturing instrument you have available and insert it in the valve of the ball, thus releasing the pressure. Let most of the air out but don't deflate the ball completely. You need it to have some air pressure for the next step. Take a look at the above stock photo to see what your ball should look like in this step.
At this point the basket-ball seems dead. No more bouncing, no more spinning on one's finger. But don't despair, as it will live again a plentiful life as a medicine ball!
Step 3: Nurse Pass Me the Drill!
Take the hand-drill and place it against the valve. You must choose a drill bit as close to the diameter of the valve as possible. With precision, drill carefully the valve thus opening a hole at that point. This will be the filling point.
Step 4: Fill the Ball!
Choose a funnel that its bottom fits the opening you created in the previous step. From these three funnels shown in the picture I used the smallest one.
Put the funnel in place and begin filling the ball with sand. You might want to do this outside because there is a chance that you spill a little sand on the floor.
Be patient as this step might take a while to be completed. Try not to rush and overfill the funnel with sand because it jams.
Instead, take a small spoon and try one spoonful at a time. If it still gets stuck, try to stir the bottom of the funnel with a thin stick.
Step 5: Seal the Deal!
As the ball fills with sand, tap its sides occasionally to compact the sand inside better. If it can't hold inside more sand remove the funnel.
Now you will have to seal the opening. When I was constructing my ball, I searched my inventory and I found among my plumbing washers these solid elastic cylindrical washers. I was lucky because they could fit snugly in the hole. I can't imagine the conventional use of such things. Maybe if one of the readers knows anything, he/she can enlighten me further.
Apply epoxy in the hole, then set in the washer. For a finishing touch, apply some more epoxy on the surface of the washer to secure it better. Leave it overnight undisturbed for the glue to set.
Step 6: Enjoy Your Heavyweight Medicine Ball!
Enjoy your medicine ball! You can search online for suitable exercises with your new ball.
Now for a word of caution. Avoid dropping your ball to the ground. Because we are dealing with a heavy object, I can't guarantee that the ball can handle such negative acceleration forces when it hits the ground. Its weak point is where the cylindrical washer is glued. The last thing you want is to rupture the ball, spilling its contents all over the place.