re: Fire Piston

A solid, air tight cylinder is essential, since the piston relies on the heat generated from air being compressed to ignite the char cloth. The one I built, long ago, was a solid brass cylinder with a bore cut into it for the piston to fit into. The o-ring and grease are needed to keep that seal. Ones that are built well work great…I could never get the hang of using it, but the buddy I gave it to love it.