Ref - History of shaped charge effect the first 100 years author Donald Kennedy
status- unclassified general distribution
Dr Munroes experiments in 1888 pressing letters into a gun cotten cube then exploding it in close proximity to a steel sheet resulting in the letters being clearly imprinted into the steel sheet was the start of research into shaped charges .
In order to demonstrate this in a school or public lecture the ideal explosive is a stoimetricmix of hydrogen and oxygen this is easily acheived by electrolysis of dilute sodium carbonate solution This works better than electrolysis of water as the sodium carbonate in solution results in an increased conduction and current flow at low safe voltages . The steel sheet is replaced by a flat layer of plasticine on a thermostatically controlled heated mat .As the temperature of the plasticine is increased it becomes softer so by varying the temperature of the plasticine we can change the amount of force nessecary to imprint upon the surface. A flattened leaf is placed on the surface. The surface is then covered with strong detergent solution or bubble mixture. The hydrogen/oxygen mix from the electrolysis unit output pipe end is pressed gently into the bubblemix so that the whole surface is covered with a layer of bubbles-our explosive. The explosive charge is fired by a lit taper . This results in a loud satisfying bang that delights the audience .By careful "tweaking" of the plasticine density clear explosive formed prints of the leaf or a coin can be stamped into the plasticine.
Plaster of paris or dental plaster can be used to take a mould of the prints to form a more permanent record of the results .
Hydrogen oxygen bubbles can be fired on your hand without damage this may have potential for stage special effects???