Water resistance testing for the hobbiest

  • Please add our email support@horologyboard.com and/or domain horologyboard.com into your whitelist to make sure emails are not filtered or blocked. If you have registered but have not received your activation email, please check you spam/junk folder. If you still cannot find your email to activate your account, please Contact Us. Thank you.

Rx4Time

Administrator
Staff member
Administrator
Dec 23, 2017
728
871
143
Ok, so you just received that beautiful, shiny new dive watch. Now you want to take it to it’s intended element...water. Just because the manufacturer has labeled it water resistant, how can we be sure? Manufacturers typically do not test every piece they produce, only a small sample meaning that you have purchased a watch which the design and assembly has been shown to be pressure resistant to the stated value. The acutal watch in your hand most likely was not tested. The last thing anyone wants is to have their beautiful new watch severely damaged or outright ruined by unintended water incursion. This article will dive into the topic of water resistance to help you protect your new prized possession. New, or used, genuine or replica, all watches have the potential to have any number of flaws reducing or eliminating water resistance, regardless of price point. The value testing at home rests in the following two statements; First, the ability to test at home carried out over the course of a few years will ultimately be less expensive then taking a series of watches to the local watchsmith yearly to verify they are still safe to submerge. Second, the cost of an economy pressure vessel ( or paying a local shop to test) is less then the cost of a movement service should you submerge a watch with a failed seal.

Water resistance explained (skip to testing if you just want to know how)

.
While the purpose of this article is not an in depth discussion, but an overview and real life practical application for a hobbyist who wishes to safely wear their watch in water. Water resistance is usually expressed in atmospheres (ATM) feet or meters. 1 ATM=10 meters= 30 ft (approximately). Below is a chart explaining the ISO 22810:2010 standards. This is a static pressure. I’m not going to enter into the debate of how much influence dynamic stresses have on water resistance. Suffice it to say that I personally test my pieces once yearly and do not swim or submurge any which cannot pass at least 3 ATM. I usually test beyond to 5 or 6 ATM, but this is a bare minimum as it shows the case can be waterproofed successfully, IE, there are no case malformations and the gaskets are all seated correctly.


water_chart4395a86e83f74373.jpg




There are factors which can affect water resistance. The first is the machneing quality of the case. If there are any imperfections, this can create a space where water can work it’s way through. Second, the seals themselves. They need to be in good condition and properly seated. It is highly advisable to use silicone lubricant when closing a caseback and on the crown seals to prevent them from binding and stretching, creating a weak spot or void where no rubber is in contact with the case and a place where a leak can occur. If the crystal is not seated properly this can also create a perfect spot for water to enter the case. Exposure to extreme temperature can cause the gaskets to swell and shrink causing a potentially catastrophic loss of water resistance. It is for this reason that it is not recommended to take any watch in a whirlpool/hot tub. Chemical exposure can also lead to gaskets drying out and failing prematurely over time. The most common chemical the average watch would be exposed to would be Chlorine in swimming pools.

Tests and equipment:
There are two types of tests, wet and dry.

Dry test, also known as an air test or vacuum test. In this test, the watch is placed in a pressure vessel which has a sensitive clamp. As the vessel has it’s air removed, creating a vacuum, the clamp measures how much the case and crystal expands. In a nut shell, the expansion is measured over a few minutes. If there is suddenly a drop back to the baseline measurements then the piece has failed and a leak is present. This test has limitations including watches with a very thick crystal may not misshape enough under a vacuum to give accurate readings. This type of test also doesn’t give any indication as to what pressure the watch is safe to, only that there is pressure resistance. This has the advantage that the movement can safely be left in place and performed after any time the caseback was opened, verifying the case and all seal’s integrity is still present.

Wet test

This is one where the watch head is placed in a pressure vessel which is partially filled with water. The watch is suspended above the water and the vessel is pressurized. After a period of time the watch is then submerged and the pressure is released. I usually allow 5 minutes for any equalization of pressures to occur. I also recommend slowly releasing the pressure after the watch has been submerged. I suggest this for the following reason: If you have a watch which was leaked and there is a sudden drop in exterior pressure, the crystal can blow out while it’s submerged and a subsequent influx of water leading to costly repairs. The advantages of this type of test include the ability to identify the source of any leaks, and the ability to vary the pressure. This is also a much more economical test as testers can be purchased from sources such as Amazon and EBay for under $200. There are also DIY tutorials which explain how to build one out of common parts available from a local hardware store.



Testing method:

I utilize a economical 6 ATM pressure tester purchased off the Bay. This gives me readings beyond any environment my watch will typically be exposed to. You will need to remove the bracelet and keep one springbar in place to hang the watch from. After filling the vessel to the line, place the watch hanging from the hook fully into the vessel, suspended above the water and tighten the top. Pressurize the vessel to the desired level. Allow a period for the pressure to equalize should a small leak be present. Gently submerge the watch in the water and slowly release the pressure. Watch carefully for any stream of bubbles that occurs. One or two bubbles are not usually a concern as air can be trapped under the bezel and other crevices. What you are looking for is a steady stream of bubbles coming from a specific location (s). If any bubble streams are noted, immediately remove the watch from the water to prevent any water from entering the case once pressure equalizes ( you have a short period in this scenario where the pressure inside is higher preventing water from entering). This type of test can be performed with the movement in place, but there are risks should the crystal dislodge or the test be performed incorrectly and water enter the case.


Other concerns of note:

Chronograph watches have additional pushers which are essentially more points of potential failure. Also, there is the added risk due to the design of pushers. They are sealed when extended, but when depressed, and seal is broken in most designs. It is for this reason that any chronograph watch without screw down pushers should not be used in swimming, even if it passes a pressure test. Even chronograph watches with screw down pushers are not ideal for swimming as there is still additional points of failure present. Also, no manufacturer will warranty any watch should water enter the case due to submersion as there are too many factors possible, many of which would ultimately be user error.


Panerai 088 undergoing a successful 5 ATM pressure test


IMG_20170526_230529.jpg

IMG_20170526_230734.jpg

IMG_20170526_230737.jpg

IMG_20170526_230743.jpg


...and yes I was aware the watch was upside down.


Here are two videos demonstrating.

Panerai 088, passing 5ATM. The bubbles are from the crevices in the bezel and crownguard.
during equillization
IMG_20180529_1328385d43f4aa987b5e49.jpg

View: https://vimeo.com/272433957


Blancpain Fifty Fathoms, failing 5 ATM. Initially it seems like it's passing, but when the pressure drops to about 2.5 ATM, look closely by the 11 oclock position, the very fine stream of bubbles indicates a small leak and I would not trust this piece swimming without having the crystal repressed and tested again.
during equillization
IMG_20180529_131334d77910dd3e85a833.jpg

View: https://vimeo.com/272434141
 
Last edited:

JackJ1980

Content Contributor
Horologist
Dec 22, 2017
1,012
881
163
For the faint of heart, you can do the first test with dial and movement removed :)
 
  • Like
Reactions: Rx4Time