Watch Water Resistance Pressure Test Fail. Seiko SKX007. Aftermarket caseback.

Just thought I'd publish this little video of my first real FAIL test. I've done over 30 watches in this machine and wouldn't now be without it.
The watch in question is my own SKX007 with a sapphire crystal, new seals, SARB059 crown and an aftermarket caseback.

My Calipso watch pressure tester is rated to 11bar.
This is a little short of the 200Meter rated water resistance of a SKX007 but as you'll see it's still a very useful test.

The process is to pressurise the container with the watch in air in the top half. If I have pinched a gasket (which is very easy to do) or there is some other fault the pressurised air will be forced into the watch case.
The next step is to immerse the watch in water (which is much harder to compress than air) and slowly release a valve manually. If there is a fault you will see a stream of bubbles exiting the watch from the weak point. Because air is escaping, water cannot enter so I could have done the test with the movement inside but when I'm building up a watch I do it before casing up.

At first I thought it was a caseback gasket but on closer inspection, the aftermarket caseback is at fault. It seems that the metal where the notches are for a caseback tool to grip is too thin.

I should just say that this machine is not sufficient on it's own to certify a watch as being a suitable tool for diving. For this, you would generally need a 3 stage test which includes a dry pressure and vacuum test, a water pressure test for a set period then a hot plate condensation test. Equipment which costs £thousands more than a simple modder (I'm not a watchmaker) like me can run to.

Sorry for the long ramble but I was interested to see the video and maybe you will be too.

Oh - the 3M tape is just to hide the identity of the caseback supplier - it was an old batch of casebacks and I believe they have rectified the problem now.

EDIT : Someone pointed out that I should start releasing the pressure gently immediately before immersion into water so as not to drive water into the case.