A method of making a photoflash lamp wherein an elongated piece of glass tubing is sealed at a first end thereof to secure a pair of lead-in wires therein. Thereafter, a quantity of primer material is positioned within the tubing through the second, open end thereof and deposited on an internal bottom surface of the tubing. A quantity of shredded combustible material (e.g. zirconium) is then air blown within the tubing member, and thereafter a thin member (mica disk) is frictionally inserted through the open end. The tubing member is then restricted, a combustion-supporting atmosphere (e.g., oxygen) introduced therein, and the second open end of the tubing member is sealed (tipped) to define the finished envelope. Use of the disk substantially eliminates the possibility of shred migration into the second open end region during sealing thereof, thus assuring a positive seal at the envelope's tip portion.