I also wanted to mention too that there were far easier ways to build a fire.

The most simple way is with a clear water bottle:  Just fill it up and use it as a magnifying glass against dark paper (dark absorbs the energy much more efficiently).  On a sunny day, this can take as little as 2 minutes.  The main issue obviously is that it needs to be done during the day so its not completely practical.

The other quick way involved using a 9V battery and some steel wool to essentially make sparks to catch on some kindle of some kind.  This too seemed pretty easy but because it involved batteries, I let that idea go for this particular project.