Any time I can run an experiment at home that replicates things I see at the test site it's a huge win. Tonight I fabricated a plugged injector plate and soldered up a chamber inner liner and throat. I used the plugged injector plate to Hydro test the chamber to failure. The chamber liner failed at 1750 PSI. It failed in exactly the same way as the chambers that failed in the field did. This liner and throat were soldered with normal relatively low temp solder.
Thursday I will solder up a throat with high temp silver solder and test that to failure.
As part of doing this test I also abused my o-ring seals, no lubricant and hammered them together. I even got o-ring slivers sliced off the injector end o-ring. Still the o-rings held and did not leak at 1750 PSI.The Snap ring retainers and the fuel feed plumbing also held the pressure. All in all a good test.
For one last reality check Plain old un alloyed copper has a work hardened to fully annealed yield strength ratio of ~5. So 1750/5 = 350PSI we were running the fuel feed at around 375.
At some level it all makes sense.