How do I brand a homemade punching bag(small)? I have rice and pillow rucksack and strings. I can't keep it...

I have rice and pillow rucksack and strings. I can't keep it tied right and the pouch breaks easily when i punch it. I own a professional speed bag but i approaching homemade ones better.
Smudges on an acrylic table!!?
Answers:    well the rice, and or seed are a good start, why not try a heavier weightiness fabric approaching burlap or cotton Duck cloth, Muslin, and craft a BAG.

Tied obviously doesn't work, why not use Grommets, and leather lace stitching at the orifice, to be put on an S hook, chain, Bungee, or similar? The "bag" might include a "bladder" of sorts that in actual fact contains the rice, then is inside the material,,,even Naughahyde, which would allow more punishment. You might even look for a Hot water bottle, or Hygene device rubber "bottle" surrounded by a tear drop or round shape?

Steven Wolf
Just my two cents
Coating on Ceramic Plate?
Have you tried satisfying a football or basketball tied up?
There are metal 'holes' or larger 'eyelets' you can clamp into fabrics at top to thread leather straps or cord.

Or possibly start out with cover bag next to the eyelets on top for drawstring & tying.