MoT's WDF

I was fully expecting all of these watches to fail so far and none of them have. Seeing where they fail and when will be exciting.

An ER doing 9bar is really impressive. If my selection of watches handle 9bar, do they really have to do any testing at all on their watches to assure 3bar?

Just a quick update.

The Easy Reader passed a test after being at 9bar overnight.

Timex Scout passed a 9bar test.

MK1 chronograph has been borrowed. I have to clean it a bit and get it into the tester.

Sporkboy wrote: ↑Thu Jan 07, 2021 11:25 am Here is what I am doing. It could be a less than ideal procedure and I should probably read up on it more. Step 1 is definitely correct. A partial decompression could be done prior to submerging the watch and then releasing further pressure. Someone in the thread mentioned it, but I haven’t gone back to read the reasoning since I built this.

1. Pressurize vessel with watch suspended above water.
2. Wait some amount of time ~10min or more
3. Release all pressure and check to make sure that the crystal doesn’t pop off.
4. Tilt vessel so that watch is fully submerged.
5. Observe for bubbles.
6. Set vessel upright again, open lid and retrieve watch.

Interesting stuff.

I think steps 3 & 4 should be swapped?

If you have a leaky watch, you fill it with air during pressurization.
Then you put it under a couple inches of water and release the pressure and see if any bubbles come out.

Cayabo wrote: ↑Tue Jan 12, 2021 11:42 pm

Sporkboy wrote: ↑Thu Jan 07, 2021 11:25 am Here is what I am doing. It could be a less than ideal procedure and I should probably read up on it more. Step 1 is definitely correct. A partial decompression could be done prior to submerging the watch and then releasing further pressure. Someone in the thread mentioned it, but I haven’t gone back to read the reasoning since I built this.

1. Pressurize vessel with watch suspended above water.
2. Wait some amount of time ~10min or more
3. Release all pressure and check to make sure that the crystal doesn’t pop off.
4. Tilt vessel so that watch is fully submerged.
5. Observe for bubbles.
6. Set vessel upright again, open lid and retrieve watch.

Interesting stuff.

I think steps 3 & 4 should be swapped?

If you have a leaky watch, you fill it with air during pressurization.
Then you put it under a couple inches of water and release the pressure and see if any bubbles come out.

Hey there [mention]Cayabo[/mention]. The reason behind at least letting some of the pressure out is to create some differential so that if there was a leak that air sour be pushing out. When you are at the same pressure and there happens to be a catastrophic leak then some water could start to seep in.

If you depressurize quickly, then you could beat the water by pushing it back out. The setup isn’t optimized for quickly dipping the watch and then depressurizing since you have to carefully tilt the whole thing on its side.

I will need to read some more procedures, but this seems to be working so far.

I really like what you're doing here and appreciate the effort you're making.


A couple inches of water won't intrude into a watch case. The case is effectively sealed due to surface tension.
It's when you put it in water and then increase the pressure that the water is driven in.
(also, dunking a warm watch into cold water can suck water in due the change in temp - this is a problem when diving into a cold lake on a hot day)

ie - you don't have to worry about getting water in your watch if all you do is put it in a couple inches of water (heat soak and pressure equalization are assumed)

What you're doing is a pressurization cycle on the watch, followed by a 3" water test.
A watch that's been reasonably sealed against dust will pass this test.

As long as you add pressure while the watch is out of the water, you don't have to worry about water intrusion.

The watch will produce bubbles above its "failure" pressure without you having to worry about damage.
(The test you're using is done on $10k watches after servicing - sometimes, the watch fails. You know they wouldn't do this if there was any chance of damaging the watch.)

Of course, you must release the pressure slowly in case the watch has allowed pressure in.
A quick release of pressure of a failing watch can pop the crystal off or do other damage...

Thank you for the information. Apparently I have a lot more reading up to do on this tool that I put together.

I tested the MK1 Chronograph and it passed a 9bar test without a problem.

This is a sample size of 1 for this model, but I am 5/5 on recently made 3bar rated Timex watches testing at 9bar. I am fairly confident that these watches are significantly more water resistant than advertised.

I would guess that these watches do have better water resistance than 3 bar.
I'm sure they experience reduced water resistance after a battery change and/or as they age, so having extra resistance to begin with would be a good idea.

I've had some Timex that leaked and I've "fixed" them by popping off the back and putting some o-ring grease on the stem and back gaskets.
(The local Time Factory store would always lube the gasket during a battery change.)


If you're willing, I'd be very interested in the following test:

1. Pressurize vessel to 9 bar with watch suspended above water.
2. Wait some amount of time ~10 min or more
3. Tilt vessel so that watch is fully submerged.
4. Release pressure very slowly.
5. Observe for bubbles.
6. Set vessel upright again, open lid and retrieve watch.

I will try that test protocol next.

I should have noted that the previous owner of the scout and Easy Reader had performed a movement t swap on these, so they have been opened up before.

[mention]Cayabo[/mention] I think you are on the right track as Following your procedure I did see a slowly forming bubble coming out of the stem. This was a previously opened watch, so some dust or something could have made it onto the stem gasket.

The bubble formed at about 3bar left on the gauge, so it was ~6bar resistant... I think. I will need to open the watch to check it out, but other projects are taking priority ATM.

I will retest the chronograph.

Interesting.

Still, that's good.
2x greater than stated water resistance on a watch that's been futz'd with.

I am following this with interest. I presume the idea of the revised Cayabo test is that the water needs to be pressurized to reflect actual water depth? Pressurizing the watch just means that you will probably be able to see any potential leaks before actual water intrusion.

You could put the watch in the water and then pump up the pressure and the water would go into the watch.

So the idea here is to do just the opposite.

Pump up the watch with air, then submerge the watch in water while the pressure is released.
Any air that got into the watch during pressurization will be seen as bubbles escaping the watch during depressurization (indicating a "leak").

If you're patient and want to be thorough, you run through the test several times and increase the pressure each time until you finally see bubbles.

[mention]Sporkboy[/mention] Happy New Year!

You need a new hobby! LOL.

Great Job!

With the new testing method of releasing pressure under water I now see the bubbles expected. The problem is that I guess I took the chrono too far and it now fails a 2bar test.

Does anyone know if the chrono pushers on the MK1 are integrated or use e-clips to retain them?