Run a small amount of Elmer's glue around the side of an end plug or the inside edge of the paper tube. Insert the end plug, convex side first, into the paper tube. Push it in until the back edge of the plug is flush with the edge of the paper tube. The paper tube should always be fused before the flash powder is added. Run a small amount of Elmer's glue around the fuse and let it dry.
Flash powder is extremely dangerous and explodes with great force.
Avoid all sources of friction, impact, flame, sparks and static electricity. Do not fill the tubes completely full or pack in the flash powder. By leaving an air space there is room for the flash powder to expand when ignited which will produce a much louder explosion. PLUG Plug the open end in the same way that you plugged the first end. 10 drops of Elmer's glue.