I think I was simply trying to get a piece of wood that was too large to catch up. I was able to get a good portion of it glowing with an ember that smoked quite a bit but couldn't get it to ignite. I started by fraying up and feathering a portion of the wood, dusting it with the magnesium, and then sparking it. The most flame I could get was somewhat small and nothing like you did in the video. They were also short lived (the flames), a few minutes max, leaving the smoldering embers which would glow hot but not catch.