Destructive testing- oven bag… just a follow-up;<br><br>I’ve continued playing with these things. As I noted in a previous post, there was some trouble keeping the top closed for this sort of abuse- the provided cinch strap was useless, and knots tended to slip. I didn’t try a twist-tie.<br><br>After several more drops from 3-4 feet the knot slipped again, and had to be re-tied again. This time I reduced the amount of water (I forgot to measure, but I’m guessing it was well over a liter, maybe a liter and a half) and made the knot very tight.<br><br>Several more drops later I was getting bored and doing spinning tosses into the tub, and it finally failed. Interestingly, the bottom seam sprung a small leak on the same toss that caused a 4 inch diameter bulge in the material, protruding about a half-inch. This would seem to mean that the seam is approximately as strong as the material- no point in it being much stronger.<br><br>Note that neither failure was catastrophic- the pinhole leak could be stopped temporarily simply by setting the bag with that part topmost (hard to describe but true), and the bulge was not a rupture.<br><br>After the pinhole leak appeared I deliberately punctured the bag with a forefinger. It was a bit harder than I thought, and the oven bag material stretched more than I thought it would, but puncture resistance is surely the weak point of any of these solutions- anything truly sharp would have ended it instantly.<br><br>Conclusions- it’s a lot more durable than I thought. I’m guessing that the “burst strength” of either the oven bags or zip-lock freezer bags is more than sufficient- in the “real world” dropping the bag would more than likely result in a puncture from a twig or sharp pebble long before the bag actually reached bursting strength. Using these for water purification in camp seems very practical, and if reasonably protected from anything sharp, I think you could backpack it cross-country.<br><br>All in all, for the very flat, compact package, I’m pretty impressed with these oven bags for the smallest kits, and they sure cost a whole lot less than the military survival water bags. I'm seriously thinking of stashing one in my wallet.<br><br><br>