Back in my service rifle competition days, I used a miner's carbide lamp to blacken my sights, as did a number of my colleagues. Just unscrew the base, add a few pieces of carbide, spit in it and reassemble it. This should produce enough gas for ordinary blacking purposes. For more gas, just add more moisture. My lamp came with a cigarette lighter type device on the reflector to light it, so no need for matches.