Unless it’s a special punch bag that’s designed to be filled with water, then you should not fill a punch bag with water. You’ll end up ruining it and it may even cause it to rot.
There are special punch bags that are filled with water, such as this one on Amazon.
These are typically tear shaped, and made from a strong rubberized material. They range in width from 15” to 21” and, when filled with water, weigh from 75 to 190 lbs.
Because water weighs so much, you need to ensure the structure you’re hanging it from is strong enough. It’s not just the weight of the bag that needs to be held but the structure also has to cope with the forces involved when the bag swings around and is being hit.
I’ve written previously on ‘how to hang a heavy bag’ in this article.
These water filled punch bags feel different to regular punch bags. A regular heavy bag is a hanging solid mass. Depending on the type of padding used, there can be little give in the bag when it’s hit. For this reason, it’s important to use proper punching gloves when hitting a punching bag. I’ve written more about this subject in this article.
A water filled punch bag has a lot more give when it’s hit and behaves much more like a human body when it’s struck. This reduces the impact on the hands and wrist and means that it’s less likely to result in an injury.
The other great advantage of water filled punch bags is that they’re highly portable. You simply need to empty the water out of the bag, unhook it from its support and transport it to its new location. When it’s empty, it’s very light and takes up very little space.
Filling a Regular Punch Bag
The weight of a filled punch bag should be about half your own actual body weight. It’s therefore important to choose materials that help you achieve this.
If you are using clothing scraps only then it’s likely that your punch bag will end up being too light and too soft.
To add weight and to increase the punch bag’s density, you’ll need to add sawdust and sand.
Sand is the heaviest and most dense material so you should be careful not to add too much or your bag will be too heavy.
I don’t simply pour the sawdust and sand directly into the bag itself. That could end up damaging it. Instead, I fill 1 quart sandwich bags with the either sand or sawdust. To prevent the bags from bursting when hit, I wrap them fully in duct tape.
I measure the weight of the bag of sand and sawdust and from that I can work out approximately how many bags I need to add in order for the bag to be the correct weight.
As I fill the bag, I layer the filling: one layer of clothes scraps, followed by one layer of sand and sawdust bags. Each layer is about a foot in length.
I surround each layer of bags with clothes scraps to further protect them from bursting. After each layer of material, I use a baseball bag to push the material down and to carefully compact it.
Once filled, I zip up the top of the punch bag and it’s ready to be hung. I’ve written an article on ‘how to hang a heavy bag’ previously.