I believe flashbulbs had some sort of combustible material coated on a filament (sort of like the sparklers seen around here at holidays). The material ignited rapidly in a burst of very high temperature which then ignited the foil. Don't know what the stuff was, but trying to buy it today would probably put me on a watch list here! I would guess it probably involved powdered magnesium and an oxidizer in some sort of binder.
Last edited by DWThomas; 02-28-2011 at 10:44 AM. Click to view previous post history.