The punching bag, or heavy bag, is an essential piece of equipment for those training in boxing, MMA, martial arts, and any other combat sports. You can buy pre-filled punching bags, but here's a tip: buying an empty punching bag is oftentimes much cheaper than buying a pre-filled one.
With the not-too-cheap shipping & freight costs in Australia, empty punching bags are often the preferred option. Filling the bag yourself can also give you better control on the bag's weight & density.
Here's how to fill punching bags:
Purchase your bag from a sporting goods store. It's important to get a bag made with materials that can withstand years of abuse, such as high-quality vinyl, canvas, or leather.
Consider how dense and heavy you want your punching bag to be. Generally speaking, your bag should weigh 0.5 pounds / 0.23kg per 1 pound / 0.45kg you weigh. Adjust the weight depending on your skill level and strength. If you're a beginner, start with a lightweight bag; You can always adjust the weight & density later on as you get stronger.
Prepare your materials. You will need scrap fabric, sand, reusable bags, duct tape, a long blunt material to pack the filling down (like a long PVC pipe).
Your old clothes will do, but you will need plenty of it. Otherwise, scrap fabric can be sourced from Op Shops.
Make sure you remove buttons or any materials other than fabric.
You will also need to shred and cut up the fabric into smaller pieces.
It's important to NOT pour the sand directly into the punching bag, as sand can damage the bag internally over time.
Instead, pour them into reusable bags. This also makes it easier for you to adjust the weight of the bag in the future.
Wrap the bags of sand with duct tape to prevent them from accidentally breaking.
Add the filling to your bag. Unzip the top of the bag. Put one bag of sand at the bottom of the punching bag. Surround the bag of sand with shredded fabric. Use the PVC pipe or any long blunt object to press down on the fabric.
Add another bag of sand every half-meter or so. Continue to layer with compressed, shredded fabric in between.
When you get to the top of the punching bag, add the last bag of sand.
It's important that you compress the fabric well to prevent the punching bag from becoming lopsided during training.
You can adjust the weight and density as you go, now that you know how to fill a punching bag.