I was intrigued and couldn't resist the dual temptations of alcoholic beverage and a novel preesure vessel. The lager was unexceptional but I liked the aluminium bottles, the necks were about the right size for a 1/2" tap so I thought what the hell and a few weeks later this was sitting on my work bench:
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I'm not really into pneumatics these days so my first though was a straight up combustion, however the power would have been puny through the 1/2" orifice, so I thought I'd add a few x
Of course this brought up the obvious problem of the beer bottles exploding so they were sleeved with aluminium tube which was cross-bolted at the end and filled with wire mesh and hot glue. This gave me a chamber sufficiently safe up to about 3x, enough for some fun.To finish off I thought I'd give it two independently firing barrels and chambers. Finally hybrids are noisy beasts so barrel shrounds / suppressors were mandatory.
Ignition is by two BBQ piezo units, one actually came out of my old barbecue which had rusted to bits (the rest gets shot in the video). The electrodes were tricky due to the wall of the chamber not really being thick enough to take a thread, i used an M8 mylon bolt with channels dremmeled down the side for enamelled winding wire electrodes, all tapped and epoxied in.
As i was determined not to buy anything for this project i didn't bother with proper unions for the burst disks, just used some pipe fittings epoxied together. This worked well although the rotating barrels gave poor accuracy (who cares, it's a shotgun)
For metering I tried JSR's syringe technique which worked flawlessly, ignition first time. I've fired this thing a lot and it's not failed to ignite the mixture a single time. It just goes to show you don't need a hundred pressure guages attached to a hybrid to get it too work, one on the pump is sufficient (for low mixes/small chambers anyway).
This is probably my favourite damage pic, this was only 1mm steel but the projectile punched a perfect full bore disk out of the target.
And finally the damage vid
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