Thanks Geo.
A little more. I bought this quite smart case with display back as I liked the crown guards and that it's only 42 mm. It still makes a huge watch as it's all dial.
Anyway, the hands were delivered with C1 lume (the white one which was what I wanted) and the dial with C3. That had to go back which was during their company holidays..... So, thought I'd pressure test the case. It's rated at 50m or 5 bar (75 pounds per square inch, psi) so I tested at 25% above that.
Here with the case above the water and 6.25 bar showing (92 psi).
If the watch leaks, then the pressure inside it equalises to 92 psi and when the pressure in this plastic cylinder is decreased, the air will come out of the watch so, before releasing the pressure, it goes into the water.
Then, bubbles will be seen. None showed here as the pressure was slowly released so, it seals fine. I forgot that picture.
There is a big problem with these sort of testers. If you drop the pressure quickly and the case has let in that pressure, then you can blow the crystal out submerging your nice rebuilt movement in the water. So, I always test first with an empty case. I've had one crystal blow doing that....
Just thinking of the force involved, this crystal has an area of about 1.5 in2 so, if there was a delta pressure of 92 psi, that would be nearly 140 lb. I usually push old crystals out from behind with my thumb so, they would clearly pop out under a tenth of that force.
Anyway, it's slowly coming together!
Cheers, Chris