Reply With QuoteGreat work there! Bookmarked for future reference.
So, I've regulated my Pelagos http://forum.tz-uk.com/showthread.ph...ing-my-Pelagos, and as of today it gains less than a second a day so pretty successful. Obviously, to do that, I had to remove the case back and although I was very diligent in replacing it, a couple of people pointed out it really should be pressure tested.
I don't have anywhere local to me that can do this sort of thing, and didn't really fancy posting the watch off to have it done, so as I'm a bit of a DIY enthusiast (I won't say expert!), I thought I'd follow a design I read about elsewhere.
I read a thread by 28800bph on the CW Forum a long time back about a DIY pressure tester that he built, so I dug out that thread again and went shopping for bits and pieces on eBay. I managed to get all the parts I needed for about £50 delivered.
I was still awaiting the 6mm SS dip tube, but had a spare RC helicopter tail boom in my RC spares box that I thought would do the job for now.
No need for me to detail the build here, as it's all on 28800bph's thread; http://www.christopherwardforum.com/...p?f=33&t=10816
So, here is the watch being mounted on the tube and after pressurising to 3 BAR (the recommended pressure for this sort of test apparently) and awaiting its fate!
Pelagos Pressure Test by iaintookey, on Flickr
Pelagos Pressure Test by iaintookey, on Flickr
After 3 minutes, I then went outside to de-pressurise it as there is a little water in the tube that escapes when the air pressure is released.
I looked nervously for any tell tale signs of a leak, but fortunately nothing from anywhere, just residual static bubbles, so very pleased.
Pelagos Pressure Test by iaintookey, on Flickr
Pelagos Pressure Test by iaintookey, on Flickr
So, I've no need to be wary of the water when washing up or bathing the little one now. It will suffice for me until it goes for a service whenever that is anyway.
Does anybody know how they pressure test these things to the original depth without risking popping out the crystal or flooding the watch when they go in for service?
Great work there! Bookmarked for future reference.
F.T.F.A.
They usually test without a movement in and then fit the movement and re-test if it passes the first one.Originally Posted by Tooks
A test to the rated depth would be carried out in a hydrostatic tester, there's a little about how I do it on this particular blog entry below.
http://thewatchbloke.co.uk/2014/12/2...x001s-grandad/
Congrats on the MacGyver test rig, very ingenious!
Interesting, thanks!
The Hydrostatic tester looks like a serious bit of kit, and not cheap I'm guessing?
When I took one of my Rolexes into their place off Oxford St about 20 years ago they pressure tested it in a machine that doesn't use water - the guy behind the counter told me they use a vacuum chamber and a laser that tests that the case contracts as expected once the normal pressure is restored.
thats what I understand most brands use, a vacuum test rather than liquid.
It's just a matter of time...
Vacuum testers are great up to 10bar and eliminate the risks associated with wet testers, they work by measuring the deflection on the crystal over a given period of time. The problem with dry vacuum testers and dive watches is the thicker the crystal (especially mineral and sapphire ones) the less likely it is to deflect enough to give a reliable reading, you also can't pinpoint the source a leak with a vacuum tester - you just know it's leaking somewhere. For testing between 10 to 20 bar you can use a high pressure wet tester, but above that and you'll have to use a hydrostatic tester. Mine goes up to 300bar (3,000m depth) or 400bar with extra clamps.
Hodinkee did a nice article explaining how it all works.
http://www.hodinkee.com/blog/under-p...stance-testing
Very cunning
Dave
Brilliant thank you for posting.
I have an old ro unit I keep meaning to throw out,
I will now save one of the filter housings & give it a go.
Interesting post and and even more interesting read.
Time for a stupid question and maybe this will show that my grey matter is slowly dying but when you increase the pressure prior to submerging the watch why would the internal pressure of the watch stabilise to the ambient air pressure if the watch is properly sealed? I'm going to do a bit of googling so i don't look like a dumb arse but after reading this thread and the links I can't quite get my head around this.
And, when pressure tested with the movement taken out how do they confirm that the watch is properly sealed once they put the movement back in.
Edit: OK, I've got. When the chamber is pressurised if there is a leak then the ambient pressure inside the watch will be at roughly the same high pressure as the container. When the pressure in the chamber is then released whilst the watch is submerged the higher pressure inside the watch due to the leak will then try and escape hence the stream of bubbles. If the watch was properly sealed then the inside of the watch will be normal pressure and nothing will try and get out when the pressure is released. Maybe I should have googled first before typing.
Last edited by IAmATeaf; 16th May 2015 at 23:55.
I use a wet tester that goes up to 6 bar, bought from Ebay and made in China. It cost around £160. It allows the watch to be submerged and withdrawn in a controlled fashion, which is vital.
I have my doubts about wet testers, and if used carelessly on a watch that's leaking they can allow water into the movement or blow the crystal out.
One thing to always consider is the safety aspect of these kits. I check mine for cracks and faults frequently; I wouldn`t want the thing to fail when it's pressurised at even 6 bar, especially when my head's near it. I wouldn`t dream of building one myself for this reason.
Wherever possible I always test a watch with the movement out. Usually I`m working on the watch anyway, so it's a good way to determine whether the case is waterproof. Old watches usually leak around the crown seal owing to a worn/perished seal or wear to the pendant tube. However, sometimes they're OK; just stripped a 70s Omega down today and it's passed a test up to 3 bar. The crown has obviously been replaced fairly recently and the caseback seal too. Getting an old watch waterproof again can be a challenge....I got lucky on this one.
Paul
Here's one thing I don`t like about wet testers:
The watch is pressurised in air, and may start to allow air into the case. Lets say the watch is OK at 2bar but starts to leak at 3bar. If left long enough the watch will reach an internal pressure of 1bar, restoring the pressure differential to a point where it isn`t allowing any more air in. If the pressure is then dropped, you would expect the watch to start expelling air bubbles when the pressure drops below 1 bar. However, it is capable of sealing with a 1bar external pressure so why shouldn`t it seal with a 1bar differential in the opposite direction? In this scenario, no air bubbles are seen, the operator continues to drop the pressure slowly....and then the crystal blows out because it can`t stand the internal pressure.
I had this happen on a Seamaster Pro which had been taken up to 6bar.
If a watch case passes the pressure test I repeat it with the watch submerged. This gives a further check that the watch hasn`t leaked; when it's stripped down again there won`t be any water inside. If the case (minus movement) passes this test I`m happy, and I`ll build the watch back up, giving it a quick test later to confirm no problems during assembly.
If a watch has virtually no water resistance the wet tester will pick it up fine; take it up to 0.5bar, leave the watch in the airspace for a few minutes, drop the pressure a fraction then dunk it under the surface. If bubbles are seen I remove it immediately and allow the air to leak out of the case by dropping the pressure slowly.......it's all too easy to blow the glass out!
These things have to be used carefully!
Paul
Yes, I totally agree Paul.
The water filter housing I used is designed for use in systems at max 120 psi, so probably rated for much more than that. I pump it up to 3BAR or approx 45 psi, so should be well within limits. I also have a 4BAR pressure release valve fitted.
The rest of the components are all 3/4" plumbing components so again good for many times 3BAR.
I just wanted to establish a basic level of water resistance, which this rig does. I can get the watch out of water extremely quickly by turning the whole thing 180 degrees. As I said before, I only do this because I'm the only one who loses out if I muck it up etc, I'm not about to start pressure testing other folks watches, that's for sure!
But yes, and again I agree, if anybody else decides to build one of these rigs, please do take care and respect it, as misuse could be harmful.
Last edited by Tooks; 17th May 2015 at 20:13.
I'd like to have a go at this - well done
What happens if the test fails? :)
I was intending to test without movement - just at low pressure for swimming etc
If you get the watch out of water sharpish if you observe any bubble streams, then there should be no damage. It's pressurised air escapng and no water should get in until pressure is equalised.
And even then, you've got to sort whatever the sealing issue is so the case can be checked for any moisture ingress and dried out if necessary.
This is where the fun can start!
A watch that's leaking will become pressurised inside. If telltale bubbles are observed, it needs pulling out of the water sharpish. The thing NOT to do is to reduce the pressure quickly to zero; this is likely to blow the glass out. It doesn`t take much pressure inside a watch to lift the glass, so the pressure inside the case has to vent slowly via the leak. I take the pressure down very carefully until it reaches zero.
Another flaw with wet testers is the assumption that air can get out via the same route of ingress. The pressure differential is in the opposite direction, so there's no certainty that it'll vent fully. Residual pressure in the case will potentially lift the glass.
Provided the drawbacks with wet testers are recognised, they are a very useful device which is relatively cheap. A pressure gauge, a means to vent the pressure in a controlled manner, and a way of getting the watch out of the water quickly are essentials IMO.
Paul
Good luck with that! :)
I always thought the 'test' was done with air pressure.
I thought 'wet testers' were used as a confirmation of water proof (for diving watches in particular) as the second stage after air testing.
You'd have to test again anyway with the movement inserted to ensure the seals are fine after opening and closing.
There are more detailed instructions on how to use it in the link I put in my first post, but briefly.
Fill the container half way with distilled water
On the tube, mount the watch so that when the lid is screwed on, the watch is out of water
With the lid screwed on, and the watch still out of water, pressurise it using a track pump to 3BAR
Wait three minutes so that any air can travel into the watch through a leaking seal etc
Turn the 'device' upside down so the watch is now in water
Using the valve, release the pressure, which travels down the hollow dip tube into atmosphere
The pressure vessel is now at ambient pressure, and if your watch has a leak, it will be above ambient
Any leak will show itself as a stream of bubbles
If you observe a bubble stream, flip the device the other way up, the watch is now out of water again
The device isn't meant as a replacement for any commercial kit, nor is it ideal for testing every kind of leak, nor can it test beyond 3BAR (well, I'm not advising it!).
I built this so that I can ensure a basic level of water resistance after I have changed a battery or opened a watch up to regulate it. It is meant as a bit of harmless, but useful, fun. :)
If I mess it up, well, people like Paul will get the resultant business!!
I think Tooks's DIY rig is probably as good as the commercially available ones.....the drawbacks of wet testers (in my opinion) are inherent with the principle and I think they need using carefully. My Chinese one's fine, but I wouldn`t want to pay big money for a Bergeon one because the drawbacks are still the same....it'll just last a lot longer than mine.
If a watch has a major leak (ie no water resistance whatsoever) the act of getting it wet in the tester will be enough to introduce water into the case. How do I know this?........I learned the hard way!
If a watch is known to have enough WR to withstand getting splashed, or immersed in very shallow water, it'll be OK in the tester provided caution is used. My approach is to only test a watch to what I think is reasonable; if it's rated to 50metres I`ll take it carefully to 5 bar, but if it's an old watch I`ll assume it's got zero WR and I wouldn`t risk it in the tester without removing the movement. Even then, if it was originally rated to 30metres I`ll be happy if I get it to 2bar; I`m referring to vintage watches which aren`t going to be deliberately immersed in water. To get the WR better would possibly involve more expense (new glass, crown) which may not be what the owner wants. Horses for courses; if all you ever do with a watch is occasionally splash it with water whilst washing up, <0.5bar is sufficient to keep it dry inside.
Even if a watch passes the wet-tester tests, I`m still slightly suspicious. I always check for condensation forming in the case, and I inspect the case very carefully for moisture ingress when taken apart. I`m far happier using it on cases with no movement and I do this to determine what (if anything) needs attention.
Paul
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