Refilling Your Sack
Recently in a help session on our support page, a customer inquired about how to go about refilling a footbag. Specifically, he was asking about how much filler to use and how to go about getting it in the footbag. We currently carry three types of footbag fill, so it only seems appropriate that we provide some guidance on how to use it. The type of fill used in a footbag, weather it’s Czech seed beads, tungsten, or our Mr. Special Sand significantly effects the bag’s performance.
The ideal quantity and mix of fill is ultimately going to be based on a player’s preference, but there are some general guidelines to follow.
- Heavier bags tend to be slightly easier to control
- Less full bags are easier to delay or stall
On the surface, it might seem that a heavy, mostly empty footbag will yield the superior performance. However, there is one more key factor to consider in this equation: The wobble factor (a term I just coined). This wobble factor is largely dependent on the size of the footbag in relation to the volume of the fill. As an example I will illustrate the hypothetical extreme case; a large, very loosely filled bag with dense filler:
Okay, so I’m not an artist, but I think the picture lends to a good starting point for discussion from an engineering perspective (I am still an engineer). The material of the bag has its own center of gravity (1 in red below). Similarly, the fill in the bag (when it’s bunched up like shown in the above picture) has a separate center of gravity (2 in red below).
Now, without getting too mathematical here, the bag as a whole (fabric + fill) has it’s own center of gravity (3 in red below).
From a footbagging perspective, so long as the center of the force (Say F3 in red below) from the kick (or set from a stall) goes through point #3 above, the bag will set or fly straight. However, when you are setting the bag from a stall or kicking it, it’s nearly impossible to impart the force of a kick or set anywhere but directly through the center of gravity of the fabric (F1 in red below).
What does this all mean? Simply put, the line of force from the foot generally goes through the center of gravity of the fabric (F1). Now, in this example of a large floppy densely filled bag, the center of gravity of the bag’s fabric (point 1) is offset from the center of gravity of the bag and the fill (point 3). Thus when a typical setting or kicking force is applied to the bag, it will have a tendancy to wobble. The greater the distance “a” is (as shown in the initial closeup of the footbag), the more wobbly the footbag will be.
There are a few other factors which play into the whole equation, but hopefully I’ve clearly illustrated the basic fallacy of the super large, underfilled footbag. The “ideal” footbag fill density is one that uniformly fills the sack - thus avoiding the case where the fill bunches up and increases the wobble factor. So in the above case, in order to minimize wobble, one can either use a smaller bag, or less dense fill.
Footbag Fill Density Chart:
| Fill Type | Density (grams/ml) | Notes |
|---|---|---|
| Tungsten | 7.0 | 14 times more dense than the average hacky sack’s fill |
| Czech seed beads | 1.4 | Less dense than sand (the beads have holes) but far less susceptible to break down |
| Mr. Special Sand | 1.7 | Potentially hazardous, susceptible to breaking down into dust |
| Cheap plastic fill | 0.5 | Commonly used in lower end footbags. |
Here’s a pictorial representation of the above table:
Keep in mind that we’re looking for a dense fill that uniformly distributes itself in the bag. Thus, unless it’s a relatively small bag like the Fearless 55, using only tungsten is going to end up making a wobbly sack. This is why other our other bags contain a mix of fills.
Finding the exact ratio of fills to meet your particular preference of fullness and stallability without the wobble factor is generally a process of trial and error. If you are refilling a 32 panel footbag, we recommend that you reference this great pictorial tutorial put together by Alex “Zeke” Ibardaloza:
Footbag Refilling Tutorial by Zeke
Note that the above method is only going to work if you are using a 32-Panel footbag with bleed holes. All of our Abshire footbags (Fearless 55, Regular and Mini) as well as our Joshua Rayes and FootFighters are sewn with bleed holes. However, if you’re looking to refill a bag like the Mr. Sandbag, you’re going to have to make your own bleed holes. This can be accomplished by carefully cutting the stitching with a pair of sewing scissors. You’ll want to pinch some sand up into the bag so that the stitching bulges out, and you can slip the scissors underneath a single stitch without catching any fabric:
Once you’ve got the bag opened up, you can use a funnel (make your own out of paper if you don’t have one) or use a straw one (like in Zeke’s tutorial) to expedite getting the fill in the sack:
Once you’ve refilled the bag to your preferred fullness, we recommend Supertacker for resealing the bag. Steri Strips will work, but don’t tend to hold up on the fuzzy material of the Mr. Sandbag as well as they work on Facile or Amaretta bags.
On a side note, I have to give credit for the title of this blog to Tasmone Mays who posted this thread on the www.footbag.org forum.
Peace.
