good link Rod, I was trying to find it. I've had better luck with the birch fungus than the
Fomes fomentarius/horse hoof myself.
Both seem to catch better if done like the youtube video, where ya scrape some off into a powdered pile and strike the flint downward on the steel sending sparks to land on it and catch.
I've tried charring the hoof stuff and using it like char cloth,,holding it on the stone and striking with little luck. There are better natural things to char and use.
The Fomes fomentarius does make a good punk, if you start it smoldering in a fire it could be carried for some time. Tried it at a camp one time, tossed it in the fire to start, then took it out and set it aside, next morning it was still going and still had much of its size left.
For Mathias,,it's very likley the same stuff, curious though, Why do you soak in birch ash? does it make it easier to use? Do you then scrape it or just use the cut piece as is?