Originally Posted By: Denis
My understanding of this is that the material in the ferro rod is softer than steel so you are scraping material off of the rod. With flint & steel, you need carbon but this is because the flint is harder than the steel and in that case you are actually scraping the material off of the blade, not the flint.


That's absolutely right. With a flint, the sparks come from the steel of the knife -- tiny shards of iron are burning. With a ferro rod, the sparks come from the rod itself -- tiny shards of cerium are what's burning.