Guide to sealing & waterproofing watches

Guide to sealing


waterproofing watches

Watches are not designed to keep the air inside but to keep water out and they are right, but if you take any watch and put it into a water pressure tester, you won’t see any leak around the crystal. The building of these watches is often complex, but needed for the reason so that the crystals are properly sealed and pressed onto watches. Here we show you how step by step!

What you’ll need:
Crystal press
Nylon dies
UV Adhesive **New stock coming soon**
UV lamp
Finger gloves
Dust blower
Microfiber cloth

Guide to sealing & waterproofing watches

Removing the crystal:

Take the crystal out, repaired crystals are usually poorly pressed, so you should be able to pop it out using only your fingers, but it’s better to use a crystal press because it reduces the risk of damaging the edges of the crystal.

Pick dies of the correct size for your watch. The side of the dies have to be quite close to the side of the crystal (1mm or less).

Removing the crystalcrystal press

Press gently but firmly, the crystal should pop out. If it doesn’t, make sure the crystal is not locked by a ring, and if it’s not, you’ll probably have to use a stronger press.

Using the crystal press

Removing a pressed bezel:

Some watches have a pressed bezel. Out of the factory, this bezel is not sealed, just pressed and the waterproofing is maintained by a rubber gasket.

On the watch it already has been sealed, so don’t try to take it off because you could damage the watch in the process, but below you’ll see a pic of what it should look like once removed.

Removing a pressed bezel

To remove it, simply use the press like you would do it for a crystal, but if you can it’s better to use metal dies instead of nylon dies (nylon dies may break).

To seal the bezel, apply silicone grease on the rubber gasket and cement on the case, before pressing the bezel back using the crystal press (be careful to place the bezel straight before pressing).


Start with removing the crystal gasket.


Once this gasket is out, clean all the parts, preferably with an ultrasonic cleaner, but if you don’t have one, a microfiber cloth, a brush and a dust blower will do the trick.

Ultrasonic cleaner

Once everything is cleaned, put the crystal gasket back in place, be careful not to touch the inside of the watch or the gasket with your bare fingers.



You can find lots of crystal sealants on the internet, but most of them have a huge downside. They intend to lose their sealing property with heat, which can be quite a problem during summer. The only ones that won’t.
Another good thing about this sealant is that it will only set with UV light, so you can continue to work on the watch even hours after you’ve applied the adhesive.
You don’t need to use a lot of it, just a tiny bit, that you’ll apply between the gasket and the top of the bezel (or the case if your watch doesn’t have a bezel).


Once the UV adhesive is applied, with your finger gloves on,  take the crystal and put it carefully on the top of the watch case. Don’t try to press, just set it as straight as possible. If the crystal is slanted when you press it back, the sealing won’t be consistent (you can even break thin sapphires!).

Using gloves

Then press the crystal back. Again, press gently but firmly, and when you feel that the crystal is back in place, press a little harder (not too hard or you may break your dies).

Press the crystal back

Carefully clean the excess of UV adhesive (which won’t be a problem since it doesn’t set without UV light).

clean the excess of UV

Put the watch under your UV lamp for 10 minutes.

UV lamp


Now the crystal is properly sealed and should be waterproofed, but to reinforce the waterproofing, we’ll apply a layer of cement around the crystal. Blurs are not really a problem as you’ll be cleaning later.


Let it set for about 2 minutes and then remove the excess glue using a wooden stick.

Remove the excess glue

Now let the cement set completely. For this one, it will be 24 hours.

Cement set