Can some explain the differences between water proof and water resistant watch cases?

Also the differences in removing and closing the backs and the preferred methods of doing so.

I have a water resistant case. It popped off easily but will not snap back on. I ordered a press and will try that.
Thanks
John Dolan

John,

This is a good question, I often feel the claim of water resistance causes a great deal of confusion and upset, people buy watches and are told that they will withstand these huge depths even the most simple watch is stamped 30 meters and how many of us have ever swam that deep so would at first sight would more than meet our needs. So the sales assistant eager to sell will tell them that they are good for all day wear, swimming, showering etc, when in fact a 30m is little more than splash proof and should be kept dry, so on up the ratings, there is no such thing as a “waterproof” watch they all fail at some pressure it maybe huge but will fail. I can pressure test watches and to do it right is a lengthy job, if the failure is more than just seals on better watches can get expensive fast. You need to be looking at a rating of 200m to even get some realistic protection for swimming, and don’t forget that lying in the sun heating the watch up to high temperatures and diving into much colder water will not help nor soap chemicals etc!
Basically if you need to get the watch wet you need to find the true “divers” rated watch, also we are talking about a brand new watch factory fresh, that is batch tested, also a true quality grade watch not a cheap import that is stamped to sell, and we also go back to who changed the battery or serviced the watch, if you had the local $5 cell changed they may well have damaged the case, seals etc, and did you ask for a full pressure test afterwards?, I give a long lecture to the shop assistants on this subject as the whole topic is important for them to know and understand, and pass onto there customers it justifies there higher cell change prices, show they customer they came to the right shop with knowledgeable staff and allows them to offer more options of service including full pressure test report, I say “report only” as once found the cure can be costly so at that stage we present the repair estimate to the customer, at that point some are happy to know the 200m tag etc will leak at the damaged case back that the $5 cell change gouged out and not to swim in it etc.
Here is some info I found;
Watches are classified by their degree of water resistance which, due to the absence of official classification standards, roughly translates to the following (1 metre ≈ 3.29 feet):[4]
Water resistance rating Suitability Remarks
Water Resistant or 30 m Suitable for everyday use. Splash/rain resistant. NOT suitable for swimming, snorkeling, water related work and fishing. NOT suitable for diving.
Water Resistant 50 m Suitable for swimming, white water rafting, no snorkeling water related work, and fishing. NOT suitable for diving.
Water Resistant 100 m Suitable for recreational surfing, swimming, snorkeling, sailing and water sports. NOT suitable for diving.
Water Resistant 200 m Suitable for professional marine activity and serious surface water sports. NOT suitable for diving.
Diver's 100 m Minimum ISO standard (ISO 6425) for scuba diving at depths NOT suitable for saturation diving. Diver's 100 m and 150 m watches are generally old(er) watches.
Diver's 200 m or 300 m Suitable for scuba diving at depths NOT suitable for saturation diving. Typical ratings for contemporary diver's watches.
Diver's 300+ m for mixed-gas diving Suitable for saturation diving (helium enriched environment). Watches designed for mixed-gas diving will have the DIVER’S WATCH L M FOR MIXED-GAS DIVING additional marking to point this out.

Sorry missed the case back question, often they can be removed easily but the pressure pressing back on will deform the case outward and make then near impossible to close without correct tools and may well damage the case, crystal, crown etc doing so any one of these parts can cost more than a cheap press if damaged on a modest quality watch in fact if you are only doing a few it make more economical sense to have the person with the correct tools do it than to invest. Prior to removing the cover you will need to thoroughly clean the entire case area to prevent dirt, body grease etc dropping in this is a major cause of failure I get many in that the shop they have changed and dirt jammed the movement whilst doing so and need much more expensive repairs, seals should be inspected replaced and lubed, there are many cheap presses out that will do a adequate job for light use some will casue more damage than good, I invested in full sets of nylon dies system, and many new type case opener that in all cost a couple of thousand dollar worth these will see me out I expect, it all depends on how much you do and how well you want to do it.

Chris,
Thank you very much for the education.
Hopefully I have not damaged the case or back.
I will try the nylon press when I get it. If it
doesn't work its off to the watchmaker.

John D

Chris,
Thank you very much for the detailed explanation of the different classifications of water resistance. I own a couple Swiss Army watches which are rated to 100m and several years ago I had the batteries replaced by a factory authorized repair facility. They charged me around $30.00 each and replaced the battery and tested the watches while I waited. When done they provided the printout from the machine they used to check for pressure leakage.

The next time the batteries went out I replaced them and kept everything clean and oiled the seal and they seem O.K. I used to swim with the watch with the stainless band as the other has leather it would be ruined by getting it wet. Since I changed the batteries I have not went swimming with the watch and I won't until the watch is pressure tested. The next time the battery needs to be changed I'll have someone do it with the proper equipment. Hopefully at that time the seals and case will still be in good enough condition to pass the pressure test.
Thanks again,
RR

Chris,

I was able to press the back back on with the use of my new press. The back was quite stubborn
though, I had to press much harder than I wanted to.
The press comes with 14 nylon disks and worked
O.K. but I am not impressed with the quality of the
tool. I recommend spending more than $36.95 to anyone who expects to use a watch press often.
John J. Dolan

Debbie sound like you had a good one there, of course another point is that watches come from anywhere who all have there own standards, I have a Breitling on the bench with a huge screw down back full seal etc a solid lump of SS , then a real weak design seal at the crown and pushers rated to 30mtrs wouldn’t you expect such a watch to have been designed to a much higher rating.
John, sounds like you got a lot of press for little money there albeit a bit rough, I have a fancy one that you can ratchet the press down close then very slowly screw the press down giving you great control as they pop closed or not and can stop before its to late, I had one last week that the case back slot in a 18K main body had been mangled and the last cell change person had tossed the seal and glued the back on!, I ended up re cutting the slot on the lathe and fitting a new seal it worked.

Chris,

What I did not like about the press was that as you pressed down the nylon dies did not meet flush. This caused the case back to slide a little as you pressed. I am assuming the pressure should be evenly distributed. The watch I worked on was a CSI college logo I bought for my
daughter upon graduating from St. Rose in Albany, N.Y. The center of the dial is interchangeable
to suit the school. She had broken off the crown with part of the stem. A little more work
than I expected. I had no clue as to the size of the stem so I bought a new quartz movement that came with a new stem. ( to be cut to size of course). Well, not a bad idea the new movement was
only $8.00 and it came in handy after I lost the screw I accidentally removed. Now I had to replace
the movement , remove and replace the hands cut and replace the stem and fit the crown. I bought
a bag of 100 crowns hoping one would match the one that was lost. I found the same watch on-line
and had a good match. Cutting the stem to the proper length would have been a lot simpler with
the original at hand but I did my best. A bit frustrating at times, but I felt pretty good when I
gave the watch back to my daughter. I hope you had a few laughs on me.
Now my question , which make and style of cutters do you use for cutting the stem. I have seen flush edge types but a brand-name would help. Are crowns tapped a standard depth say .05
mm? I have some cheap quartz watches to practice on for fun.

Thanks,
John D.

John, Sound like you had all the fun you can there, some days a simple fix like that goes wrong and can cost a fortune in lost time materials.
The crowns vary in depth, the trick is to have the movement fitted in the case correctly no stem at this point find the crown that fits the case correctly and of course fits the stem.
You fit the crown to the stem full length of the new stem, fit that into the movement and press into run position, the stem crown will protrude out of the case on the extended stem, measure the gap between case and case side of crown, make a note, remove stem take off crown mark the stem with that measurement just taken, then snip it off leaving a little extra to shape the head, now using a pin vice grind the head down at a angle on a stone while rotating to make a cone shape down to your mark I have a electric hone that makes this and many other jobs easier, fit crown insert and if you got it right ok, if to short, dig deep and get another stem!

Chris,
Thanks again for the fix. Let me know when you put out a DVD.

John