I think you just melt candle wax, dip the makeup pad into the wax, remove and let harden/dry. The wax will be water repellent and act as your fuel source. When ready to use, break the pad in half to expose the dry, uncoated cotton (to catch your spark), and you are in business.
I basically did the same thing with a box of non-applicator tampons and candle wax (red). I still have the ones I made and still have about 60 tampons floating around my house, garage, boo kit, BOB, and car. Protip: if you let the wax get too hot, it turns very liquid and will just soak into the makeup pad/tampon. You only need it to get just hotter than liquid form so it is still thick enough to not be absorbed by the cotton.