Have you ever tried to start a fire with one of those magnesium fire starters that they sell at any sporting goods store and even walmart. The plus sides..they are cheap, wetness does not affect them, they are small, lightweight, and will produce a guaranteed spark if you follow the simple instructions. So, have you ever tried to actually build a fire with one of these?
Imagine this, you are out in the woods, and because you found this handy dandy fire starter for just a couple dollars you figured, hey, it will work to get me warm and to have heat to make smores. Sounds logical, right? (totally hypothetical) So you get out to the woods and pull out your magnesium fire starter. You pull out a pocket knife to shave the magnesium. After an hour of scraping, you might have enough shavings to equal the dime sized pile you are supposed to have to build a fire. That is, if it isn't windy and they didnt all blow away as you scraped, making your efforts fruitless. (or in this case, fireless). So you turn it over, strike the knife against the side and waalaa you have a spark. Ok, now you just have to figure out how to get that spark to go in the right direction and to land on the pile you worked so diligently to make. Another hour passes, and suddenly, there it is, a spark lands on the magnesium. You have the fire you wanted, except now when you add the rest of the essentials of a fire, you realize that bedtime has arrived because you spent all evening trying to build the fire. So you stop adding fuel and sit, watching the stars, wondering, will the fire ever die so you can go to sleep? You worked too hard to put water on this fire, if you are lucky, maybe a spark will remain for a breakfast fire.
That was totally hypothetical, but this month during our Outdoor Skills programs at work, I am in charge of teaching wilderness survival which includes a large part of fire building, and I have been having the kids attempt to build fires using different methods, one of which is the magnesium block. Even with some charclothe provided by one of our youth volunteers, those kids would never have gotten a fire started. The match and dryer lint worked much better!
So give it a try sometime, see how well you fare at building fire with a magnesium fire starter, then be thankful that you have not relied on it, pull out some waterproof matches and build your fire!