Just like we used a water bottle filled with water to make a lens, we can use a balloon as well. Clear balloons work best, although most light colored balloons will be somewhat see-through when stretched. To use a balloon, fill it with water, just like the water bottle, and tie it off. Don’t stretch the balloon to its limit, as you may need to squash it slightly to form a good lens. While functional, this method does take more experimentation than anything we’ve talked about up to this point.
A common form of “balloon” to use for this type of fire starter is a condom. Many survival instructors recommend keeping a couple of condoms in your survival kit; Condoms are usually made out of high quality latex, so they are much stronger than most commercially sold balloons.
Another common form of balloon for a fire starter is a latex medical glove. Yes, you can actually use these for something other than making chickens for the kids. Once again, the glove has to be filled with water and tied off. However, the natural shape of the glove makes the palm part of it a pretty good lens, which doesn’t have to be reshaped to work.