When I filled mine, I used........
children's ( They're now called "kids") washed "Play Sand". I cut the flange off a Bonanza .17 cal. funnel, chamfered & deburred it, & put the bag in a plastic dishpan half full of sand, which you can frequently get at a discount from building suppliers if the original bag's been broken. I filled the "ears" of the rabbit ear bag first, & packed it in tightly, as I knew that shortly it would settle & I'd have to re-pack; then packed the base. While filling the base & rasslin' the bag around, I put the "ear" fill tubes just in, but not all the way under the ears. When all was filled, & packed, I got out some spray silicone like you'd use for boot dressing, & gave the bag, the ears, & the upside & downside of the fillers a coat of dressing, then when it had dried, a second application, then tucked away the fillers using a popsicle stick to help it along & keep 'em flat & neat. Don't forget to put this on the underside of the bag, too, as sometimes you'll put the bag down, & there may be some barely noticeable dew before the sun's burnt it off the benchtop. I did the same for the top bag on the pedestal, but to compress the bag a bit & forestall settling, I held it by the filler & whacked it a few times smartly on its bottom & put more sand in, then repeated the 2-step water repellant application. Now the ears on the rear bag are fairly "grippable", & I may not have to add any more sand for quite some time, rather than two more times as I had to do w/my first bag fills. The bag on the pedestal is nice & firm, too. I found using the slender funnel was great, as you don't force the fillers open & distort them. Also, when the cavities start to get full, you can just fill the funnel, & start pushing the tube up & down repeatedly & this will pack the sand in the bags to the operator's taste, then you stop. Much simpler than the first bags I ever filled. And, sooner or later, you can add another application of silicone, and this'll keep the bag supple, and forestall the drying or water absorption of the leather somewhat. I imagine this works for the Cordura bags, too. Hope this helps you out.
