Low dome acrylic crystal problem

[Russell]

Hello,

I'm new to this forum and I heard a lot of good things about this forum, so I hope I can learn new things.

I have a watch with a low dome acrylic crystal, I have never work with low dome crystals before, so I find this quite confusing. The diameter of the crystal is about 20mm and the diameter inside of the bezel is 19.2mm. When I pop out the crystal I notice some tiny cracks around the crystal's edge that meets the bezel, I thought it wasn't a big of a deal, something that I can just polish off later on, but turns out it wasn't. Any ways, I tried to put the crystal back into the watch, but it's very hard I tried using the crystal lift but it didn't work and damage the crystal even further. I did some research and found out that low dome crystals are meant to fit into the bezel easily and secured with glue or cement, is this right? I do find the measurements of the crystal and inside of the bezel to be very odd. 

I also need to find new crystals for this watch, what size crystal should I get? the smallest one I can find is 19.4mm

Thank you very much for your help and advice.

Best,

Russell

Edited January 14 by Russell
incomplete title

[watchweasol]

Hi  The first thing we need is the make and caliber of the watch and a few pictures of the movement, case / front and back and of the old crystal, Armed with that information we can proceed. There is little point in guessing or aproximating sizes  as it will lead to mistakes.  You say the dis of the crystal is "about" 20mm,  best to measure it exactly with a vernier gauge and have some hard facts to go on..  A good web site to look at is Esslingers .com in America  they have various tutorial pages to do with watch repair and one which deals with measuring and fitting of crystals.

[jdm]

2 hours ago, Russell said:

Any ways, I tried to put the crystal back into the watch, but it's very hard I tried using the crystal lift but it didn't work and damage the crystal even further.

Avoid clamping crystal lifts, acrylic crystal are best removed and refit with a crystal press and the correct dies. The STK catalog has a brief section on that.

[Marc]

3 hours ago, Russell said:

low dome crystals are meant to fit into the bezel easily and secured with glue or cement, is this right?

No, not if they are round actylic crystals., you shouldn't need any glue at all.

Crystal lift type tools are not very good at all with low domed crystals, and not the best for fitting any crystals. As @jdm mentioned above a crystal press with the correct dies is your best bet.

Have a search of the forum on how to use a crystal press.

[Russell]

This the watch I'm working on @watchweasol. And I do not have access to a crystal press, is there any other option other than using a crystal press??

[jdm]

2 minutes ago, Russell said:

.And I do not have access to a crystal press, is there any other option other than using a crystal press??

A crystal /  caseback press is indispensable tool. Some decent ones are not bery expensive, check pinned topic below. That being said most often on acrylic crystals a bit of filing around and GS Hypocement is all it takes to fit by hand and have them stay there.

 

[watchweasol]

Hi  If a crystal press/lift is out of the question the only recourse is as jdm recomends, and that is filing or sanding the crystal to fit using either Hypo crystal cement or a UV equivelent.

[Russell]

I bought a crystal press a while back for 20-25 bucks from Amazon and the thread that connects the dies to the tool are slightly bent, not visible at first but once I attach it to the tool it's pretty obvious the die face isn't parallel to the ground.

@jdm @watchweasolthanks for the advices. I'll try sanding the crystal

[rodabod]

One of the issues with the common modern presses is that they do only that - press the crystal. 
 

What you often need for acrylic crystals without tension ring is a set which allows you to deform the crystal by using a cup and a corresponding dome to compress the crystal over.