How to fill your exercise sandbag and which fill to use
The most important thing to recognize is that the density of some fill might be too high causing you sandbag to be overloaded. For example using pea gravel in your White Lion Athletics Sandbags will void the warranty because more than 10lbs of pea gravel can fit in each fill bag.
When it comes down to choosing between playground sand and rubber mulch why don't you consider using both?
How to use playground sand and rubber mulch as fill for your exercise sandbag?
The 'problem' with having all of your fill bags filled with the same filler
This might not be a problem as much as it is a challenge. If all of your fill bags are filled with sand for example then each one will weigh the same weight. That will bring the total weight of the sandbag up to 60 pounds at least. What if you are trying a new exercise and require less weight or you are doing an endurance workout and 60 pounds will be too much to complete the session with?
The obvious option would be to remove some of the fill bags from the shell to reduce the overall weight. A potential issue with this is that the size and shape of the sandbag might change causing it to sag and otherwise "flop around" because there will be less than six fill bags filling the shell.
A better option for reducing the weight load
if you fill one of our fill bags with rubber mulch it will weigh approximately 3.5lbs -4lbs depending on the size of the mulch particles.
Therefore, you might fill three out of the six fill bags with mulch for a combined total of 10.5 pounds and leave the remainder filled with sand (9.3lbs-9.5lbs each) for a combine total of 27.9lbs-28.5lbs. The total weight for all fill bags will be 38.4lbs - 39lbs.
In this scenario, the weight load of the sandbag will be less than 60 pounds but the size and shape of a sandbag will remain relatively the same.
This might get messy.....
Who has time to change out the contents of the fill bags; and, where will you store the sand and not make a mess in the mean time?
One method that we have found to be extremely effective for loading sand into the fill bags is to place the sand into a vacuum sealed bag and weigh out 9.3lbs-9.5lbs pounds. After it's weighed out, we then seal the bag air-tight with a vacuum sealer and put it inside to fill bag.
This method works great for a couple of reasons. First the sand is completely protected from any moisture; and, even if this bag does spring a hole in it for some reason, the chances of sand coming out of that bag as well as a fill bag are very low. Secondly: having the sand in a sealed bag makes it very easy to remove from the fill bag so another type of filler (such as rubber mulch) can be placed inside the full bag without any hassle.
With vacuum sealing the bags in mind, we now have a method in place to quickly change the fill in our sandbags without making a mess .
Why Not Both?
Being able to change out the weight in your sandbag quickly and conveniently might not only benefit your training in that session but it might also allow you train with your sandbag more often as its weight will not be the limiting factor. Switching out between rubber mulch and playground sand will be relatively pain free if the sand is in vacuum sealed bags inside your fill bags
About the Author
DJ Guzda, MA : Partner and Co-Founder of White Lion Athletics. Kettlebell coach (Agatsu L1); Steel Mace Flow L1 (Hons); Steel Mace Specialist (Rik Brown).