I like the finely divided metal idea for heat transfer, but I worry about possible safety concerns. The more finely divided any reagent is, the more surface area to volume it has, and thus the more quickly it can react. For instance, the thermite reaction involves finely divided aluminum reacting with finely divided rust.
Even if you created thermite accidentally due to your aluminium powder being contaminated with rust, you're still far below the temperature required to initiate combustion. A torch flame wouldn't even do that, you need something substantially higher like burning magnesium to light it.