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Ok, so nothing in this thread makes me think that I should build a dry testing unit. A decent gauge is $300 and it's still not nearly as sensitive as the purpose built Witschi one. On top of that there is no software to do proper calculation for deflection, pressure and rate of change tide into the system. In all, I'd be guessing if the watch is water tight or not. On the other hand - no bubbles and we are good to go. I'll stick with my water based tester for now.
 

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Ok, so nothing in this thread makes me think that I should build a dry testing unit. A decent gauge is $300 and it's still not nearly as sensitive as the purpose built Witschi one. On top of that there is no software to do proper calculation for deflection, pressure and rate of change tide into the system. In all, I'd be guessing if the watch is water tight or not. On the other hand - no bubbles and we are good to go. I'll stick with my water based tester for now.

Yeah, it seems like water testing is the more reliable and repeatable home-built affordable option. Limits seem to be bursting resistance of the container and available air pump/pressure.

I'm sure i'll blow $40 outta the water, but i'm thinking that it would be nice to have something that could test higher than 10 bar. inexpensive hydraulic ram would or should be easy enough to adapt
 

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This is mine:


This is slightly more expensive because of the dial indicator. It would be better if the dial indicator were better.
So the principle behind this is, if the system goes under pressure, the dial should move? If it doesn't, then it leaks? I guess it moves and stays, but if it moves and goes back, then its leaking?
 

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That's correct cuevobat!

Usually a non diver watch with mineral or sapphire crystal is bending about 50 - 100 µm with pressure 3-5 bar. For example my O&W MP2824 (with sapphire) was bending 70 µm with 3,5 bar pressure. As mentioned above a Seiko SKX007 was bending 25 µm with 3,5 bar pressure. It is a stiff diver with replaced 3 mm sapphire crystal! So far there is no problem with too stiff cases.

My dial indicator by the way costs around 40 €. It is accurate enough to see bending +- 10 µm.

If there is slow leaking and and a crystal is vintage acrylic crystal, it can be pop up when the pressure is released. It has happened couple times in my tester. I'm glad that the tester was dry...
 

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Reviving this thread to say thank you to the OP for posting up his build - I've ordered the components and look forward to building my own sub €40 wet tester.
 

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Reviving this thread to say thank you to the OP for posting up his build - I've ordered the components and look forward to building my own sub €40 wet tester.
Oh wow. Thanks for the thread bump. This is perfect for testing my modded watches!!

And a bigger thanks to the OP for showing us this easy and cheap method of testing our watches.


Sent from the White House on the tax payers dime.
 

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In part because I'm puzzled and irked by the difference between a published WR rating (e.g 50 m.) and the prose version of appropriate water-related uses of that watch (e.g. shallow kitchen sinks), I built a wet pressure chamber. So far I've tested it to 350 psi (~240 m., fresh water) and have no leaks. I have a higher pressure regulator ordered and will test the chamber for 300 m. use (meaning to take it to +50% or so when completely filled with water).

So I started using it today, choosing a 40 yr. old Seiko quartz diver with nominal WR of 100 m.

I first took it "down" to 50m, left it dry for abt. an hour, then bled the chamber and flipped it immediately. So what did I see?

I dunno.

I saw 3-4 bubbles coming from around the bezel over 3 or so minutes. What I don't know is, did the air come from within the case, or was it trapped outside the case but under the rotating bezel. I could have removed the bezel, but didn't.

I retested the then-wet watch to 100 m. No apparent bubbles, which suggests that the case didn't leak, or that it did leak massively, so that in the 3-4 seconds it took to bleed and invert the chamber, the case wouldn't still be under pressure.

A way to resolve this question would be to pressurize a submerged watch. I think this would be a more reliable test, but with obvious consequences. I'll try this with a cheap watch I don't mind flooding.

I thought about dry/wet testing a watch, then wet testing it while putting the chamber in an old fashioned paint shaker, subjecting the case to g-forces while under pressure. And it'd be easy to heat/cool the chamber. Stay tuned.

Is there a better liquid than water to use? Alcohol, maybe? Or liquefied Freon(s)? In such cases, flooding would be easier to remedy.

One could also pressurize an air-diver with helium, bleed it suddenly to see if the crystal blows out. What fun!

Any suggestions welcomed!
 

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Great thread. Thanks all.

Lokifish with regard to the Vostoks (of which I have a few so I know their sealing mechanism) I don't quite understand why 100 psi air pressure would be any different to 100psi water pressure. I would have thought the same pressure acting on the same area would generate the same clamping force??

If i'm reading it correctly, the methodology is a bit off from standard procedures.

Standard "bubble" test is;

Partially fill container
Insert watch but do not immerse
Pressurize and wait five minutes
Immerse watch (if you see a steady steam of bubbles, remove immediately)
Slowly release pressure and check for a consistent release of bubbles.

If bubbles are present then it's a fail
If no bubbles are present then it's a pass

Your approach would only work if there was a very slow leak which introduced a delay in pressure equalization in the watch. In the event of a more serious leak, it would allow ingress. I also cannot recommend either methods for compression cases like Vostoks as they rely on water pressure to be water resistant.
 

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Great write up!! I contacted Pentair technical and talked with a very helpful engineer. He said that the opaque(blue) bowl is slightly stronger than the clear bowl but BOTH of them are failure tested to 500psi.

They do this on a routine basis to ensure safe housings. The opaque bowl is more impact resistant than the clear but they both test safely to 500psi. Suprisingly their clear material, SAN(Styrene acrylonitrile resin) Performs better than Polycarbonate (Lexan) in testing.

500psi would be 345M/1121ft, so testing to 10bar/100m/325ft/146psi is easy for this setup. I have taken mine to 20bar/200m/650ft/290psi but not with a watch in it yet. So 30bar/300m/975ft/438psi might work but I dont have the cojones or the compressor to do that.....

BTW I was wearing eye protection, Face shield, welding gloves and my Carharrt coat when I took it to 20 bar. And only the ground.....
 

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Great project!
But I think the procedure given in the first and later posts for the wet tester is not quite right.
My understanding is you first do a dry test (pressurization and depressurization with no water in the test vessel), to make sure the crystal doesn't pop out, and then you do the wet test, but a bit different from what has been written here so far: you pressurize with the watch above the water level, lower the watch (or invert your vessel), wait a moment for air trapped outside the case to escape (e.g. bubbles trapped under crown, or in lug holes), and then depressurize with the watch under water while watching for bubbles.
That way you see both fast and slow leaks.
 

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im gonna give this a go.... thanks OP.


and when I test my mod's now I just take the movement out and fully seal the case. Only variable is me screwing down the case back correctly when I put the movement/dial module back in.


why keep the movement in? lol no point in risking it.
 

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I want to make an experiment to see if there will be any differences if we test watch water pressure in soft or sea water for instance? I have watched a video where a guy is making a test in 2 different waters. I can’t remember what waters were, but he affirmed that the figures weren’t the same in the end. At the moment, I don’t have a water softener to realize my experiment, but soon I will buy one from purewaterguide.net and see if there are any chances to make a new discovery. What do you think will be the final results? Will be a huge difference?
 
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