As others have stated (and I know this is an old thread, but I'm still going to post) you should really leave the testing to the professionals when it comes to the water resistance of your watch. A single point measurement of the air-tightness of your watch under very controlled conditions provides no guarantee that the gaskets won't fail the next time you expose it to less than ideal conditions.
I suspect that the testers you are/were considering are used to merely check that the seals were properly seated at the time of assembly. The best predictor of failure (assuming the seals have been installed correctly) is the age of the o-rings/seals. Think of it like how they maintain an airplane - as soon as the part/system has been in service for a set period of time (ideally, something like 3 standard deviations below the mean time to failure), the part/system is replaced and correct installation is verified before the plane is returned to service. They don't test the planes until they fail, they replace the parts before they fail as part of a regular service interval - something I'd suggest you do for your watches!
coltstrong wrote:
I'd suggest the shower is more dangerous than the pool or ocean provided you just wash down the watch with fresh water after use. I live on the water and have thank good God access to multiple pools at different houses so I went swimming all the time. After years of use and pretty much no service not one of the watches except like the cheap Casios have issues.
I did have an issue with a logines (sp) conquest in the shower though. Being a physics major I can break this down whether you choose to believe it is up to you but it is the truth and lab demonstrable although I will not defend this or set up an experiment for you.. Static water at similar atmospheres presents ionic bonding and lower molecular energy states. Whereas steam presents a much more excited group of molecules that are traveling much faster and on their own in terms of only traveling as one individual excited molecule moving much faster than water and expanding until it hits something else, like your gaskets. Unless your boiling water the steam produced is usually a rare state of h2o which is more excited, the same reason why some water evaporates under cool conditions. So your talking the same h2o but in water they bond ionically (at the least), when excited to gas they go off individually and are in a gaseous state which is more energetic and expands more than solids and waters i.e. an excited gas will exert more strain on your watch than water likely will because of the size and the excitation of the h2o molecules. They can also deform gaskets easier because of their latent heat energy.
I just realized this thread is old
Boy oh boy is that some physics mumbo jumbo!

I'm just having a little fun - I'm a chemical engineer, so I'll try to translate for everyone.
Simply put, steam is hotter than liquid water and, as a result of being a gas, will permeate more readily through elastomeric materials. This heat can lead to deformation of the seal/o-ring (death for water resistance) or accelerate chemical decomposition, leading to further permeation and degradation and so on (death spiral).