As most of you know, I built a sealed hybrid vessel recently to test the limits of 2" sch40 steel.
(more pictures will be posted on request, be specific though)
I finally got around to testing this earlier today.
Final test results: Inconclusive!!
That's right, I could not cause a failure in the test hybrid with the pressures I could reach. I may continue testing if I ever build a high pressure pump.
Test specifications to take note of:
Chamber volume: 750 ML
Chamber material: 2" diameter sch 40 galvanized steel. approx 12" long
Ignition: camera flash+ignition coil
Fuel: Propane/air
Single spark gap, centered.
Chamber obstructions: significant
Temperature: ~63F in the shade
Initial/starting test mix: 5x 60psi
Final test mix: 11x ~160 psi
NOTE THAT I DID NOT DRILL INTO THE CHAMBER to create a spark gap. I drilled into a smaller pipe nipple and added a significant amount of jbweld to ensure a good seal.
The spark gap was placed in the center of the chamber. There is a large amount of excess wire in the chamber which would shorten the distance needed to create a DDT, but it apparently did not have any effect on the tests.
Upon ignition, this hybrid gives a small "squeak", which I assume is gas seeping past the ball valve seals. I was not close enough to tell for sure.
After ignition at higher mixes, the chamber was literally burning hot to the touch. I let it cool of for a couple minutes between tests.
So, in conclusion, I would encourage everyone to use this test as a baseline for judging the limits of their own hybrid. Remote firing is a still a must, as this hybrid is probably not the same as yours.
Edit: I just opened up the chamber today, and the entire inside is covered with some type of black goop. I have no idea what it is, as the only thing in that I got in the chamber before was a couple drops of pipe dope. This doesn't even smell like pipe dope. It's also gumming up the ball valve.
