Pressure testing to 5 atm with home made tester

[KBH]

The pictures are mostly self explanatory but I'll toss out a few helpful hints.

The old duct tape trick. Almost never fails.

Using a straight pin to remove stem on the 2813 movement.

Silicone lube for o-rings from my pool supply store.

And my Home Depot special. The air valve is just a regular tire valve epoxied in after drilling a hole. It's put in from the other side and epoxied on both sides. This allows you to increase the pressure easily with a bicycle pump or compressor if you want to go higher. I can go to 10 atm using my compressor but I feel that 5 is good for everyday swimming and beach use.

And an old compressor gauge from my spare parts bin.

Just fill up the chamber with water and drop the watch in and seal it up. Use Teflon plumbers tape.

Most household pressure should be about 70 pounds which is almost equivalent to 5 atmospheres. Leave the watch in for 5 minutes to make sure, although generally you'll see the pressure go down quickly if there's a leak.

Release the pressure via either the tire valve or the hose bib before opening.

Another successful test! Dry with no sign of leaking.

 

[Bardamu]

Wow ! That's great !

I didn't think that it could be possible to make a "home made" tester for water resistance. Very clever tool.

Congratulations for doing it, and thanks for sharing !

Paul

 

[Hazardmanlog]

Thats AWSOME!!! I need one these. You should make them and sell them. I would buy one if it didnt cost to much.

 

[rol_man]

Great tutorial and tester design. Should be stickied!

 

[glippy01]

That was inspirational! I'm off to the Depot to buy parts!

 

[TESLA760]

You can make this a lot easier. Delete the tee. Buy a second bushing reducer and put it up top. Spin on a gas test block. It has the air inlet and a built in gauge. Just need to use an MIP and FIP in the middle so you can open and close the capsule.

 

[KBH]

You can make this a lot easier. Delete the tee. Buy a second bushing reducer and put it up top. Spin on a gas test block. It has the air inlet and a built in gauge. Just need to use an MIP and FIP in the middle so you can open and close the capsule.

Huh? Sounds cool but:

:ttiwwop:

 

[TESLA760]

Haha. I'll put it together next week. Need to find some scrap pipe

 

[trailboss99]

OK, now this is fine with household water pressure but there is no way I'd pressurise that pipe with air! PVC pipe, when it blows doesn't split it shatters. If that rig went boom you would have a grenade. Large bore poly pipe (ag pipe, the black stuff) would be a lot safer. Not only will it hold higher pressure when it bursts it just splits a seam instead of shattering. This is why it's used to launch fireworks and why you don't use PVC for the same purpose.

 

[TESLA760]

Schedule 40 PVC is commonly used in water systems exceeding 100psi. The appropriate primer and glue is recommended. But he is using it at a safe level. The circumstance you mention is common in pipe that has been exposed to the elements for long periods of time. If you want to put more pressure to it, just use schedule 80.

 

[KBH]

I wouldn't worry too much about it bursting. The required minimum burst pressure for 2" schedule 40 is 890 psi and the maximum operating pressure is 166 psi. Even using my 5 hp compressor I couldn't exceed that pressure.

I think the first thing to blow if anything would be the gauge out of the end.

 

[Wiz]

Don't want to be a party crusher here, but you can't know if your watch leaks based on such a test, unless we're talking major leak.

A "regular" leak will only leave traces of water, which basically cannot be seen with the naked eye.

What could help knowing if water got in is, after taking the watch out of the water, heating the back of the watch with a hair dryer, face up, and then to put it in the freezer for a few feconds, still face up.

If you can see fog under the crystal, it means the watch leaked. And still, that's not a perfect test.

For a home made pressure tester the better option is this: forum.replica-watch.info/vb/showthread.php/build-pressure-tester-28682
Even if I don't recomment it, as pressuring anything that hasn't been made for that purpose could be a very bad idea.

The "blind" testers you sometimes see on videos in the factories of major brands are not here to check for leaks, but to see if the case, crystal, .... crushes under very high pressure.

 

[KBH]

I'd have to kind of disagree with you Wiz. We're just trying to figure out if it's safe to swim with a watch and I don't believe there's a better measurement than by submerging it in water at the same or greater simulated pressure as you would find swimming or diving. This isn't meant to be a high tech solution to find the saturation of gas molecules at pressure, just a simple test that is available to everyone who's interested.

Two things I've found are, if there is any kind of leak with pressure exerted on a vessel filled with 100% water, you will see an almost immediate drop in pressure since water does not compress. And second, should there be a leak, the longer you leave it submerged, the more water will enter the case until the pressure is equalized. That's why I suggested leaving it in the water for at least 5 minutes. If you see no pressure decrease in 5 minutes at full pressure, you can be pretty darn sure that nothing is getting in your watch case.

I think for around $25 this tester does a good job of what it was designed to do. The downside, of course, is you have to de-case the movement and the put it all back together again which has the potential for introducing new leaks at the case back gasket, although I think the odds of that are very slim.

 

[Wiz]

I think I haven't expressed myself correctly. Sorry about that, English is not my first language. I try my best but nuances are sometimes hard to express.

Of course the method is correct for letting water going in (if it has to go in), what I mean is that it's not the best method to *check* if water went in. I hope you understand what I mean.

What I noticed from experience is that in most cases the leaks are really really small, and will only leave traces of water enter the watch, traces that are very hard to see, even with a loupe, but that's still enough water to create rust inside the watch.

The only customer I had who came in with a watch that has been completly filled with water left the crown unscrewed. Other than that water damages came from very small leaking points.

As for drops of pressure, the only times I could clearly see one on the manometer occured when there were huge leaks. In most case I coudn't see such a drop, and I always leave watches in the tester for at least 15 minutes (If I recall correctly you need 30 minutes for the ISO norm, but I'm not 100% sure).

 

[KBH]

The reason you wouldn't see large drops in pressure in the normal watch testor is because most testers are half filled with air and air compresses, while water doesn't. For the pressure to drop from 70 psi to 0 in a water filled cylinder would probably be less than a couple of drops. I feel quite confident that if there is no pressure drop in 5 minutes, the case is water tight. Worst case scenario is if the case does get the least amount of moisture, as you are suggesting, it will show up in fogging the crystal before any permanent damage could be done. So far I've found it 100% accurate for my watches and I always wear them in the pool and to the beach.

I've also tried another theory of pressurizing the cylinder with just air and the unfortunate side effect was that when there is a leak and the case pressurizes to 100 psi or whatever I've taken it to, the sudden release of pressure invariably blows the crystal out. My theory of pressurizing with air and then taking the watch out and placing it in water to see if bubbles escape, which is what most testers do, didn't work out.

 

[Wiz]

Once again, I might not have expresed myself properly.

If I understood everything correctly, you assume that for any watch that is leaking, you will see a pressure drop, no matter how big or small the leak is. Of course I can only talk from my experience, but I think this assumption is wrong.

There is a reason why I believe that.

I do notice drops of pressure on my tester on occasions, but only when a watch is seriously leaking. Even if air compresses, when the watch leaks really bad the space available for air to expand becomes larger, and the manometer will notice a drop of pressure.

On the other hand, when the leak is "normal", the manometer doesn't move at all. Maybe it would after hours, but 15 minutes is not enough to fill the whole watch case with air at the same pressure as it is in the chamber.

And such a leak is enough to let water go in. Not enough to turn it into a fish tank, but enough to make some parts to rust.

It's good that you never had any issue with watches tested using this method, but as I said, I've seen watches leaking without seing even the slighest drop of pressure, so if I have to make a guess, I'd say maybe luck also has a little to do with it.

I'm pretty confident that if tested on enough watches, this method will turn out being inefficient.

But again, that's just my opinion, based on my experience. People with different experiences may think different, and that is very fine.

About the other method, the reason why your crystals are popping out is because you release the pressure too quickly. If the air release is gentle and regular the crystal will stay in place and you'll see the bubbles (or not).

 

[KBH]

I think you express yourself most excellently. You English is better than lots of American's that I know.

The point i was trying to make, which you may have missed, is that reading a pressure drop from a container of liquid is totally different than reading a pressure drop from a container of gas. Since liquids such as oil, water, etc. do not compress, the slightest difference in pressure is immediately noticeable, even rather miniscule amounts. It may only go down a couple of pounds but you'll definitely see a gradual decrease. When you introduce pressurized gasses such as oxygen (or air) into you tester it takes a much more significant amount of leakage to register a change in pressure on a gauge.

An interesting case was my SSD that I've been swimming with for years. I tested it and it failed even after lots of beach time and even some skin diving to around 20 feet. I originally thought it was the HE valve and it still failed after epoxying that shut. Then after the second test, I found a small amount of moisture coming in through the crystal. After gluing in the crystal, it's all good again. Remember, this watch had been used in the water for 2 years and never leaked, so apparently the tester works.

And, unfortunately my tester doesn't really allow for a very gradual release of pressure. That's why I indicated that the air pressurization method didn't work well.

Nobody is saying this is a perfect replacement for an expensive professional tester. But I think it works pretty good for what is it. I can feel quite comfortable after testing that I don't have to take my watch off when swimming, although I do usually keep a close eye on them the first few times I swim with them, just in case.

 

[Wiz]

Thanks for clarifying mate.

I did understood what you meant. I'm just really not sure a watch with a small leak would leak enough to show a significant drop of pressure in just 5 minutes.

Maybe you're right, but even though I've seen a fairly large range of leak testers, I haven't seen any other that works like yours. And as I feel some people much smarter than us thought about that before, I'd be tempted to say that if it was a valid leak testing technic, there would been some testers exploiting it.

About what you experienced with your SSD, what we need to remember is that it's much easier for air to enter a watch than it is for water, so very often, a watch will hold deeper in real life condition than it will in an air-based tester. Also, you can go down much deeper than the depth the watch was tested for, as long as you just go down and up again. You wont' stay long enough for water to go in. Leave the watch at the bottom for some time and it's probably be another story.

There is no need for some expensive equipment, for example here was the first tester I built. Not that professional! :lol:

Also there is still the tester shown by mucrewbtp, which even if it doesn't feel like the safest thing is the world at least works with a well-tried principle.

 

[TESLA760]

I wouldn't worry too much about it bursting. The required minimum burst pressure for 2" schedule 40 is 890 psi and the maximum operating pressure is 166 psi. Even using my 5 hp compressor I couldn't exceed that pressure.

I think the first thing to blow if anything would be the gauge out of the end.

Due to my field of expertise , I will tell you that there are many variables that affect that chart. It may be true for a piece of actual pvc. But when you make a contraption like the one we are talking about, there are many other variables. Like glue, fittings, condition of the pipe. I recommend using Sch 80, just to be safe.

 

[Chris v.]

Very cool, I have seen similar but used with a nalgene water bottle. I might make one myself using one of my old nalgene bottles


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