Method of joining plastic base and cover components of a photographic flashlamp unit

Abstract From the Canadian patent

The plastic base and light-transmitting cover components of a percussive-type photographic flashlamp unit are joined together by chemically softening the rim of one (or both) of the components and pressing them together until the plastic hardens and sets. Softening is achieved with a solvent and a uniform layer of solvent is preferably applied to the rim of the cover by pressing the latter against a resilient porous applicator and the assembled components are rapidly bonded to one another by subjecting them to heated air which partially cures the seal. The units can thus be mass-produced without any danger of vibrating the percussive flashlamps and accidentally firing them.