I've tried two different approaches to making a medicine ball that you can slam, but neither has held up to even a few slams. First attempt was a rubber playground ball stuffed with sand and with the hole stuffed with a rubber patch and glued with epoxy. Probably got 100 slams out of it before it failed spectacularly (i.e. big cleanup job). I had high hopes for my next attempt: got a cheap rubber basketball (much more rigid sides than the playground ball), cut 1-inch flap (still attached on one side) in it and filled it with sand. Folded the flap back down, used a piece of inner tube and Goo to make a patch, and sealed it up. It really seemed like it was going to hold up well. I got good coverage and adhesion on the patch. Ten slams later and the ball split from one of the corners of my cut flap to just outside the patch. The patch held fine, but cutting the ball clearly compromised it's structural integrity irretrievably.
Lessons learned so far:
- A playground ball full of sand weighs around 14 pounds.
- A basketball full of sand weighs around 23 pounds.
- Making a homemade slammable medicine ball is tricky (but making one that holds up under less extreme usage should be easy).
- If you don't want to go heavy, Walmart sells an 8-pound ball for around $16.
I might try one more thing: I read somewhere that if you submerge a bicycle pump in water as you are pumping up a ball you can fill the ball with water. Seems like a good approach, as the ball stays intact, and I imagine you could slam with the same impunity as an air-filled ball. Not sure if you end up with water in the pump that you then can't clear, though.
