If you mean for a homemade bag. My Uncle made one with the sack they gave him in the Navy (can't remember the proper name for it atm) and filled it with old clothes. You could fill yours with a combination of things, sawdust works really well if you have access to it. You don't want any solid objects in there. Don't use sand for two reasons. I wouldn't use sand because it will travel to the bottom of the bag if you do.
The other reason being it could break your hand because it is really dense. I almost forgot to add that lol
Yeah sand sounds like a nightmare. The bags at my gym are filled with white cloth stuff. It pops out every time land a hard punch. Can't imagine sand leaking all over the place!
I once did a low roundhouse (leg kick) on one of those long bags. It was filled with sand that had settled in the bottom. I quickly learned it was a bad idea.
Thornpipe is correct. Find someone who makes cloths, ask them if they could save the cuts, offer them a bit of money, should work, it did for me.
