I was out camping recently, and found that the bottom foot or so of my sleeping bag had gotten wet ( in part due to one of the stakes for my rain fly coming loose, but that's another story). As no one likes sleeping with feet in a wet sleeping bag, I was forced to curl myself up, which is an uncomfortable way to sleep as well.
That got me thinking; is it possible to waterproof a sleeping bag? I have some waterproofing spray that I used on my boots and part of a tent, and it says that it is usable on nylon, suede, leather, and Gore-Tex. I was wondering how effective it would be, and whether it would damage my sleeping bag in some way. I was considering only spraying the waterproofing on the bottom foot or so of the bag, since I had seen things mentioning that waterproofing can remove the breathability of the bag.