Gadgetfreak has an explosive DIY oxygen-propane cannon –
When Ed Nauman fires his oxygen-propane cannon, anybody within range of the shock wave will definitely see stars. It’s been known to shatter windows 30 ft to the rear! Propane is mixed with oxygen under control of a PIC microcontroller, in a barrel made from a 330 ftÂ³ nitrogen tank and detonated by remote control. It’s even instrumented to measure the kaboom — he’s recorded 180 dB SPL (think two sticks of dynamite).
Oxygen-Propane Cannon Tests the Big Bang Theory – Link.