How to fill your Workout Sandbags filler bags

 Key points:

  • Do not try to see how much weight you can get into any bag.  The whole point of sandbag training is having a LOOSE, shifty bag.  So keep it LOOSE.
  • Be sure to use CLEAN, DRY sand.  Whether you get it at a hardware store in 50# bags, or dig it up in the wild, it must be clean and DRY.  Wet sand will mildew and ruin your bag.  And, it will clump up and not shift properly.  Wild sand can be cleaned by passing it thru a window screen.
  • Filler bags will appear to be only half full when stood up on their bottom end.  They are full, because the sand balloons out on the bottom, and when you spread it out it flattens out to allow maximum shifting.  And, the outer bag will not hold a stuffed filler bag.
  • Close the hook/loop closure as shown in the video to prevent creases from forming in between the hook and loop which would allow leaks.
  • Rubber mulch pellets will give about half the weight of sand in any size.
  • Less sand can be used to make a lighter bag.
  • 2 filler bags can be used with half the weight each to be able to adjust weight quickly

How to fill Workout Sandbags with contractor bags

Key points:

  • Contractor bags supplied free and come with no warranty or promise.  But, they have served many customers for years.  They will work for 2-4 years without leaks if and only if you do not change them and leave them alone.
  • Contractor bags are not for quick-changing the load.
  • Again, do not try to see how much weight you can get into the contractor bags.  This defeats the purpose of sandbag training.  Keep it LOOSE so the load will shift.
  • More contractor bags like these are at Ace Hardware.  Get the Iron Hold 55 gallon size bags for all size outer bags.  The 42 gallon size bags will fit the small size only.
  • If you weigh the sand before filling the contractor bags, shoot for a little less than the maximum capacity per size to start. 
  • Roll or fold up the excess bag and either duct tape it or rubber band it shut.
  • Rubber mulch pellets can be used for about half the weight of sand.  Of course, you can always use less sand.


 Never over-fill your sandbags.   If you must slam the bags, be sure to fill them quite loosely, about 3/4 of their maximum capacity.  Use some fatigue matting on the floor.  Even though they will take it, do not drop them from over shoulder height.  They are made to be used on floors or cement, not gravel or rough surfaces. Do not leave them out in the sun for days on end. If you must, wash them on gentle cycle and hang dry. Take care of them and they will last you a lifetime. Thank you for your purchase!  Let us know how you like them. Keep the bags LOOSE. Keep it fun!


Contractor bags are supplied with every outer bag purchase that does not choose our filler bags.  We throw them in for free.  We offer no guarantee on the contractor bags.  The contractor bags are not for quick-changing.  The affordable price of doing it this way allows you to buy another size.  Fill them, close them, and use them.  Above all , keep them loose and DO NOT OVERFILL THEM. 

You can purchase more contractor bags at Ace Hardware.  Get the Iron Hold 42 gallon bags for small and medium outer bags, and the Iron Hold 55 gallon bags for the large and extra large outer bags.

For best results, keep your sandbags LOOSE. I recommend about 90% of their full capacity. That is 40-50# for small, about 90-100# for medium, and 140-150# for large bags. They can be underfilled to almost half these weights to suit your needs.

Use CLEAN, DRY sand.  The best source for this is from a home center, buying their 50# bags of play sand.  If you must use sand from a beach/riverbank/desert, make sure it is DRY and CLEAN. Get dry sand by shoveling only the top few inches of sand.  If necessary, clean it by passing it through a window screen.

Any size sandbag can be filled with half these weights with rubber mulch, also available at home centers.

Use two 55 gallon contractor bags for all size sandbags,  If you choose, you can use your duct tape to close them permanently. Oherwise, use the large rubber band included.  It works fine.

first step in filling workout sandbags



1   Put one inner bag inside the other, with corners matching. Double them up for all size outer bags.  




exercise sandbags being filled, step two



2 Fold back a collar (to keep sand from between the bags), and add a couple of coffee cans full of sand into it. 



third step in filling workout sandbags


3    Put inner bags with this small amount of sand into one end of outer bag.



training sandbags being filled, step 4



 4 Add more sand into inner bags. Make sure not to get sand either between the inner bags or in the outer bag.


step 5 in filling workout sandbags


5    Push sand into the corners with your hand in the sand.



sixth step in filling exercise sandbags


  6     Add enough sand to get the bag full enough to where the sand is going to the other end.


filling workout sandbags, step seven

7 Push the sand into the corners of the other end with your hand in the sand.  Add more sand.



gym sandbags being filled, step eight



8    Push the air out of the excess bag, flatten it, and fold it under itself like your were wrapping a gift.


workout sandbags filling, step 9



9 Fold it down into flat segments about the width of your hand.



filling fitness sandbags10 Twist the folded flap up on itself in order to be able to attach the giant rubber band included. You should do this before you permanently close the inner bags with duct tape. If duct taping shut, do not twist, but make a flat hand-width foldup of the flap, and duct tape around it.



workout sandbags being filled, step 11

11 Fold the last flap in half and use the giant rubber band to hold it closed by doubling the rubber band up. You can use the sandbag for years with the rubber band. But, if you choose, you can duct tape around the foldup for a more permanent closure. Here is where you would duct tape it.


exercise sandbags after filling, step 12

12 Close the sandbag.  Drop it a few times on its side to pack the sand.  Open and re-close it if necessary to make the hook and loop match up. If it is too hard to make the hook and loop match up, you are using too much sand to keep the bag loose. So lose some sand and close it again.


Work out with the bag and add or remove sand to adjust the looseness of the sand. But remember, the whole purpose of sandbag training is to have a loose, shifting bag of sand. So keep the bag loose to maximize the benefits of sandbag training.


Here's how to fill your ballistic nylon filler bags:

Just like filling the contractor bags, use sand that is CLEAN and DRY for filling filler and snake bags.  You can either buy it in 50# bags from a home center or go to a nearby beach, riverbank, or desert.  If using sand from those or other outdoor locations, be sure it is CLEAN and DRY.  To get dry sand, obviously go to get it after a dry spell.  Then use a shovel and take only the top few inches of the sand.  Wet sand will be deeper.  Clean sand is not as important as with the contractor bags above, but still take out any sticks or pebbles.

Any size filler bag can be filled with rubber mulch pellets, which will give about half the weight of the same volume of sand.  It is available at home centers also.


filling workout sandbags onebag


1   Roll the top end back with its hook/loop closure over on itself to make a "collar".




filling training sandbags allinone


2  Add sand.  Try to keep the sand out of the hook/loop.  If you get some in, brush it off.




 filling fitness sandbags


 3  Add enough sand to make the bag appear to be about half-filled.  It will bunch up on the bottom, and ballon out.  Do not add too much sand.  The whole purpose of sandbag training is to have a LOOSE bag of sand so it will shift.

workout sandbags being filled


 4 Restore the hook/loop flap to its final position.





fitness sandbags being filled



5   Now it is time to close the hook/loop.  It is very important to get them aligned straight to keep the sand from leaking.  Start by opening it all the way up.  Then while holding it apart, start closing the inside edge of one side.

 fitness training sandbags being filled

6  Close the hook onto the loop all the way across the inside side of the bag.




filling exercise sandbags


 7   Now close the hook onto the loop from the back (inside) of the bag to the front (toward camera).  Roll it so as to avoid getting creases in it.  Avoiding creases in both directions is the key to having a leakproof bag.


training sandbags being filled


 8  Press the hook/loop together, and you're ready to rock and roll!  Remember, avoid any creases in either direction to stay leakproof.  Grab the bag by the fabric so as to grab some sand and that makes your handle.  This can be done either on the sides of the ends of the bag.  For 1000D filler bags, put the filler bag into the outer bag one end at a time, and close the hook/loop on the outer bag.

After 7 years of customers using the contractor bags to hold the sand, they have proven themselves to be reliable, leakproof, and durable for holding the sand.  It allows us to concentrate all of your price on the outer bag, using stronger materials. However, if you must have filler bags, we have some to go with the outer bags.  Ours use only one filler bag per outer bag to keep the sand shifting as a whole.