Water Resistance Testing - What are the recommended limits?

[Toadtorrent]

Hi Folks,

OK...I'm a Noob when it comes to Home Brew pressure testing for water resistance of watches.

I made myself a Home Brew Pressure Tester as found in the link.

When pumping things up, I had a hard time getting the lid tight enough to pump past about 75 psi. I used a Nalgene branded bottle.

I tried to follow the instructions as found in Water Resistance Testing.

At 75psi the following reps seemed to pass fine:

• Ulysse Nardin 45mm Marine Diver
  
• Cheapo Omega SMP
  
• Rolex Milgauss
  
  
  I tested my Breitling Skyland, and there seemed to be small slow bubbles forming around the chrono pushers but no fast leaks...so this seems to me that it would likely be fine washing dishes and some splashes, but probably not the best for prolonged swimming...definitely not for diving.
  
  Does this sound right?
  
  The Milgauss was funny...tested fine...no problems...but a couple minutes later, condensation formed inside, and a couple more minutes later, condensation was gone.
  
  Rats. Something is not right. But, what does this mean??
  
  I opened up the caseback and stuck it in a baggie with silica gel to dry things out...I'll test again later...but who knows.
  
  Any suggestions?
  
  At 75psi, do you think this would be fine for swimming? This seems to my understanding, that 75 psi =
  
  • 15 psi for atmosphere
    
  • 45 psi added
    
  • = 50 m / ~165 feet water resistance or hopefully fine in a swimming pool but not diving
    

  Is this right??? Thanks for any help.

[hiker01]

I don't trust my home brew tester anymore, I found a watchsmith that don't ask questions about your watch. I pay him $15 per and he test it up to 10ATM. If it doesn't pop before it reaches that, then I dive with it!

Hopefully you'll find the same in your not too distant nieghborhood!

Goodluck!

F-

[Toadtorrent]

Hopefully you'll find the same in your not too distant nieghborhood!

I haven't found a cheap one yet...all the testers I've seen are all pretty expensive...more than 2x that amount!!

[Jkay]

I could swear that there is a semi-scientifical, but much ballyhoo'd guideline for this ... taken from a "diving blog" ... or some such thing. It's been quoted here a few times ... TO THE SEARCH BOX! I'll edit this when I find something.

edit: A quick Google search shows that a watch MUST BE rated to 5 Atmospheres (150ft depth) if you wish to wash your face while wearing it. Who among us could have guessed that the water pressure on my face is equal to that found 150ft below the surface of the Sea. Astonishing. Here's the link to the page with the chart, graph, info, and over-reactions. LINKY!

I suspect lawyers were involved in the development and canonization of these guidelines.

[Toadtorrent]

Thanks JKay...I had the information from previous searches "in theory"...was wondering what people thought "in combat". Like you, 5 atm is what the total pressure in the system seemed to be that I created:

• (15 psi + 60 psi = ~75 psi) = (1 atm + 4 atm = 5 atm)
  

...also wanted to make sure I interpreted this right...as that seems so high a required rating for a little more than a 50m dash in the rain!

[wombat247]

You should start from 0 psi. Since you'll almost always start your "dive" at sea level. The 75psi you're measuring inside the bottle is actually 75 additional psi so it should be measured as indicated by the dial.

[panerai153]

I tried to build one of the Nalgene bottle pressure testers. I got the bottle airtight with the auto tire valve installed. My problem was the "el cheapo" tire pump i bought was too flimsy to work well. i ended up buying a real tester from offshore" According to the instructions, they recommend 3 atmos (this is supposedly what the watch repair shops offer) my tester will go up to 6+ atmos, however they warn that repeated frequent use at those pressures will result in premature component failure.

After testing all my watches, i have come to this conclusion: DON'T trust what the dealers say about water resistance. Their's is just a sales spiel.

I have a post in another thread with the watches, sellers and results, however I will say about 50-60% of mine failed. Both of my PAM's (failed around crown/stem seals), a couple of my Rolex reps failed, both of them were around the crystal, and all my WM9/BK and MBW reps passed.My WM9 16610 V3 sub passed 6 atmos.

No matter what the recommendations are, I believe that if your watch is WR to 3 atmos, you can wash dishes and wash your hands OK, at 5 atmos WR I would feel safe swimming in a pool. For diving, snorkeling and water under pressure, I wouldn't trust anything less than probably 50 atmos, although the chart in the link says 20.

One of the problems with testing for extreme depths is the cost of the tester. Your average watch shop may have a Bergeron or equivalent that goes to 6-10 atmos. but when you need to test for 50-100 and above, you are looking at a very expensive piece of equipment, usually only found at big repair facilities and watch manufacturers.I feel certain all the RSC's have high pressure testers, but unfortunately, they aren't available to us!!

[Jkay]

A 50 atm watch ... that's a 500 meter depth rating. You are saying you would not trust a GEN SUBMARINER for simple snorkeling.

I'm absolutely not faulting you .. I know what "big balling" is .. it happens in every hobby. The tales get bigger and bigger until everyone who has an old GTO has a "Judge" and everyone with a Mustang has an original Shelby 500. Human nature .. and completely understandable.

Unfortunately I feel that a lot of that big balling has crept into the formation of this guide for depth ratings vis a vis wearing watches in water, and it's not a helpful guideline anymore. It's a fish story; a tale of caution told by bearded men in dockside bars with shark heads on the walls.

"Gather 'round me lads, and I'll tell ye a tale of water resistance that'll make yer salty hearts tremble ... yarrr."

[Toadtorrent]

You should start from 0 psi. Since you'll almost always start your "dive" at sea level. The 75psi you're measuring inside the bottle is actually 75 additional psi so it should be measured as indicated by the dial.

The issue is that at "sea level", atmospheric pressure is about 15psi...which is why you start at 1atm rather than 0psi.

So, I think my previous thinking was off. That, when the pressure gauge reads ~75psi, that is 75psi added, which is adding 5 atm (5 x 15 psi) which is a total of 5 atm + 1 atm of pressure on the watch as we start at 1 atm or 15 psi.

[jmb]

You need to take into account that the majority of the gages you will run into read "gage pressure" which accounts for the 1 atm and start at zero. Specific text should read "inflate to xx psig" which is pounds per square inch gage. In a gage that reads "absolute pressure" zero would be a complete vaccuum. Of course, this all depends on my remembering stuff from a semester of pneumatics I took in college many moons ago...

[Nanuq]

I just chuck mine in a bucket of boiling water and watch for bubbles.

Unfortunately every single one of them has tons of bubbles. I don't get it.

[kbh]

Here's a general formula. This doesn't include variables such as current atmospheric pressure, salt vs fresh water, etc. This also assumes pressure is applied at one atmosphere.

Pressure = (depth X 15)/33

Example:

40lbs pressure = (depth) x 15)/33

40 x 33/15 = 88' depth

**************************

1 atm pressure = approx 15 psi

1 atm pressure = approx 33 feet

[Toadtorrent]

I just chuck mine in a bucket of boiling water and watch for bubbles.

Unfortunately every single one of them has tons of bubbles. I don't get it.

Hah...I had to think about this one. I tried that throwing it in the tub when the kids are in for their baths...but there are often bubbles there too...followed by cries of "stinky" and lots of laughing.

You need to take into account that the majority of the gages you will run into read "gage pressure" which accounts for the 1 atm and start at zero.

Aaah...got it. Good point.

Here's a general formula.

Pressure = (depth X 15)/33

So...if gauge pressure (starting at zero) reads about 75 psi:

75 psi = (depth * 15)/33

Solving for depth yields: 165' or 50 m or 5 atm.

So this should be good for light swimming but not snorkelling or diving or deeper water swimming.

My brain hurts. I have a tendency to waaay over complicate things...you should have seen my Halloween pumpkins...no triangle eyes there.

[kbh]

I've got to believe that the depth charts that watch companies want you to believe are very conservative. I've been wearing a SSD for close to 3 years and it's been in the beach, my pool, and even skin diving to around 20 feet on many occasions and it never leaked. I pressure tested it and found the crystal leaked at 5 atmospheres yet it never showed any signs of water penetration in the years of use.

Also on the same topic, my Noobmariner, WM9 v3, Omega PO, Josh's 1665 vintage all passed 5 atm. The one that I was the most confident in is the only one that failed.

Edit: And yes 75 lbs = roughly 5 Atm. That's what I was using.

Edited November 1, 2010 by kbh

[Toadtorrent]

Also on the same topic, my Noobmariner, WM9 v3, Omega PO, Josh's 1665 vintage all passed 5 atm. The one that I was the most confident in is the only one that failed.

Edit: And yes 75 lbs = roughly 5 Atm. That's what I was using.

Excellent to hear. This was what I was hoping for. Good stuff. I was very pleased my El-Cheapo-Priced-But-Completely-Awesome-UN-Marine-Diver passed...as that watch is so designed for the pool.

[Jkay]

Unfortunately every single one of them has tons of bubbles. I don't get it.