How damaging is this? I have a Mora and am happy to have a go but only if it wont wreck it?? Can any steel be used or does it have to be carbon steel, can I use a piece of mesh fence or a nail?
Knives DO NOT WORK to get sparks from REAL flint for fire starting. **REPEAT THAT** Knives DO NOT WORK as a traditional flint striker!!!!! Trying to use one will scratch the back of your knife! Not to mention being dangers to operate like that.
Knife blades generally have enough carbon content in their steel, but they are heat-treated waaaaaay tooooo soft to use as a traditional flint striker.
What you are trying to do is chip/dig out little bits of the steel with a sharp edge of your flint. The energy you put in to chip/dig out those little bits of steel heats them up enough that the carbon in those bits of steel burns. That's the sparks you see/get. To do so, the steel must be heat-treated HARD - almost as hard as you can get it. But that also makes it kind of brittle - so you take a few other steps to aleviate that. Kknife blades are initially heat-treated HARD, but are then tempered back far more so that they are not as brittle. Simple high carbon steel works best. But some of the other metal alloys mixed in with some steels can interfere with sparking. No, common fencing or nails have too low of a carbon content. Think along the lines of Files, chisels, or garage door springs.
One big problem is people confuse those modern FERRO CERRIUM rods (called "fire steels" or "flint" by marketing departments) with a traditional Flint Striker - the ORIGINAL fire steel. (They were called fire steels way back in the Middle Ages already.) Those ferro cerrium rods are the same material that is in a cigarette lighter, and is a modern composite material. All you have to do is scrape them with a sharp edge to get showers of sparks. So there is a lot of confusion out there whenever anybody talks about a Fire Steel.
So don't try to use a knife blade as a traditional flint striker. It will be very hard to get any sparks, and will scratch up your knife blade.
Just my humble thoughts to share. Take them as such.
Mikey - yee ol' grumpy blacksmith out in the Hinterlands