Replacing rectangular watch crystals

[PaulnKC]

All,

 

Hope everyone is staying safe and well.

I have two new "project" watches that have a common issue. I suppose very simple and straight forward, but that's if you have the experience.

The two watches have square/rectangular crystals that need to be replaced or affixed.

The first is the easiest. So, I'll start with that. It's a vintage ladies Girard-Perregaux tank. With a square crystal. The crystal is in good condition, but loose. The crystal is acrylic - and I believe the proper way for this to be fixed to the case is using something like GS crystal cement. But would like to ask here to see if this is correct.

The second watch is a vintage men's LeCoultre tank. The crystal isn't acrylic - so, I guess it must be mineral crystal (it's certainly not sapphire). It's rectangular and I presume this should also be glued in. The original isn't loose in this watch, but it's badly scratched (and not being acrylic, I have no way to buff it out - and would probably rather replace anyway). So, wondering about the best way to remove this one (in addition to replacing).

I'll include a few pics of the LeCoultre. It's going to be a bit of work. But I will enjoy it that much more if I am able to give this one a new lease on life.

Many thanks for any input posted.

-Paul

 

[rduckwor]

Acrylic crystals can be cemented as you said with GS Hypo Cement.  Often they will require some filing to fit.  I mark one corner  with a sharpie and orient this to the stem slot on the case.  I then will file the opposite long edge and the bottom edge until I get a snap fit.  then I polish the filed edges with PolyWatch to remove the file marks.  Look carefully at all four edges.  Many times you are going to have some clean-up to do on all the edges.

 

Most (but not all) crystals push out from the back side.

 

As for fitting the mineral crystal, you may have a real job on your hands it it doesn't fit.  Perhaps a good sandpaper or maybe even diamond paste will grind it to fit.  Hopefully someone else will come along and tell both of us how to fit it.

Good Luck,

RMD

[PaulnKC]

10 hours ago, rduckwor said:

Acrylic crystals can be cemented as you said with GS Hypo Cement.  Often they will require some filing to fit.  I mark one corner  with a sharpie and orient this to the stem slot on the case.  I then will file the opposite long edge and the bottom edge until I get a snap fit.  then I polish the filed edges with PolyWatch to remove the file marks.  Look carefully at all four edges.  Many times you are going to have some clean-up to do on all the edges.

 

Most (but not all) crystals push out from the back side.

 

As for fitting the mineral crystal, you may have a real job on your hands it it doesn't fit.  Perhaps a good sandpaper or maybe even diamond paste will grind it to fit.  Hopefully someone else will come along and tell both of us how to fit it.

Good Luck,

RMD

RMD,

Thanks for the post.

That sounds like a good technique on the acrylic.

 

I have ordered some GS Hypo that I plan to use on the ladies Girard-Perregaux. Not sure if that crystal is original, but it's nice and will be great once it's re-glued.

Here's a pic of that one...

I think this is a great piece. It even came on a brand new unworn Girard-Perregaux lizard strap. It could use a service and a little adjusting - but running pretty well as-is.

 

I also ordered a (small) blank sheet of acrylic to cut a replacement for the LeCoultre. I could probably live with mineral crystal on that watch (since I wouldn't expose it to any abuse) but I think acrylic is a much better choice for replacement.

I expect cutting and fitting mineral crystal requires some tooling that I don't care to invest in.

I'll post some pics of the finished work.

Thanks again!

-Paul

[Klassiker]

The glass in the LeCoultre looks curved in both directions, or is it just the reflection? It looks to be glued in, and if so you will get good results with the replacement using the cement you have bought. If you can't get an exact fit, you will have to buy oversize and grind down the edges.

Luckily for me, my wife used to be into stained-glass craftworking, so we have a diamond wheel with water circulation. I used it to do something similar a while ago, and that worked really well. As you say, a lot of work though.

[PaulnKC]

59 minutes ago, Klassiker said:

The glass in the LeCoultre looks curved in both directions, or is it just the reflection? It looks to be glued in, and if so you will get good results with the replacement using the cement you have bought. If you can't get an exact fit, you will have to buy oversize and grind down the edges.

Luckily for me, my wife used to be into stained-glass craftworking, so we have a diamond wheel with water circulation. I used it to do something similar a while ago, and that worked really well. As you say, a lot of work though.

Klassiker,

Very good eye. Yes, it arched/curved in both directions. Sort of.

The top of the glass is dead flat. As is the base where it mounts. But the side of the glass closest to the dial is arched in both directions. Like a concave lens.

It's a nice detail - but I don't think I'd be able to find it's exact replacement. I guess if I do find the correct lens in the future, I can always install it. But in the meantime, cutting and trimming acrylic is probably going to work best for me.

-Paul

[Redwood]

These look about right https://www.cousinsuk.com/product/rectangularsquare-sternkreuz-rx

[PaulnKC]

1 hour ago, Redwood said:

These look about right https://www.cousinsuk.com/product/rectangularsquare-sternkreuz-rx

Redwood,

Very kind of you to post!

Yes, I had looked through those. But the dimensions of the LeCoultre crystal are: 20.6 x 15.4

Those skip from 20.5 x 13.0 to 20.5 x 19.0. They list a 20.6, but only as a square.

So, I don't think any of those are close enough to trim down. Would you agree?

-Paul

[Redwood]

Quite right, make your own is the only option, 

[PaulnKC]

Here is the Ladies GP "checkerboard" after re-cementing the crystal.

Also did a little clean up on the dial - cleaned the hands - polished the face of the crystal.

 

My "blank" material will be here tomorrow - so, hoping to start cutting on that after work.

-Paul

[PaulnKC]

1 hour ago, Redwood said:

Quite right, make your own is the only option, 

And if I ever find a more correct solution - I can always upgrade.

-Paul

[PaulnKC]

Update...

Well, I received my blank material - and cut a beautifully fitting flat (on both sides) replacement.

Not quite a snap-fit after polishing the edges, but no spare room either. So, I was reasonably pleased with the first effort.

Before gluing in to the bezel, I thought I'd check to see if a crystal that was flat (not arched) on the bottom, would fit in to the bezel without interfering with the canon pinion. As, it seemed like there was very little room in that space. And sure enough. The crystal needs to arched on the underside - or otherwise raised above the level where the edge of the crystal sits. 

So, I'll need to use the original - or find a replacement that will leave some room for the pinion and hands.

-Paul

[Klassiker]

What about warming and forming an oversize blank, then cutting to size?

[PaulnKC]

35 minutes ago, Klassiker said:

What about warming and forming an oversize blank, then cutting to size?

Hummm...

I hadn’t thought of that. But I like the idea!

Thanks!

[JohnD]

Surely Cousins have something HERE suitable as a starting point........

[PaulnKC]

3 hours ago, JohnD said:

Surely Cousins have something HERE suitable as a starting point........

John,

Yes - one would think. But if they do, I haven't been able to find it.

Thanks for posting the hint though. Much appreciated.

-Paul

[JohnD]

3 hours ago, PaulnKC said:

John,

Yes - one would think. But if they do, I haven't been able to find it.

Thanks for posting the hint though. Much appreciated.

-Paul

Would have thought that THIS ONE (21 x 16, about 0.010" off all four sides to fit) would have been ideal... They state 'rough edges, file to fit'....

Edited May 14, 2020 by JohnD

[Klassiker]

JohnD is right. FANCY143A or RE210170 certainly worth a look.

[PaulnKC]

3 minutes ago, Klassiker said:

JohnD is right. FANCY143A or RE210170 certainly worth a look.

Yep - You guys are awesome for taking the time to look at the details.

I had looked at the rough edges, file to fit - and thought that they were "flat" - which wouldn't help.

But looking again - I think the RE210160 will work. As long as it's arched - as it appears to be from the image.

Anyway - I (we) will find out. I ordered one of those.

I need to get down to 20.6 x 15.35.

So, 0.2 off of each end running in the long direction (the short edges); and a little more than 0.3 off the other way.

Again - many thanks - VERY nice of you to search - after I couldn't find it.

-Paul

[PaulnKC]

All - here's an update on the LeCoultre tank.

Again, many thanks to John D and Klassiker!

I ordered the SternKreuz "Standard" R 210 x 160 (Cousins # RE210160). What I didn't realize was that the "extra" file-to-fit edges are beyond the measurements listed. So, there was a bit more fitting to do that I thought. None the less, it worked very well (in my opinion). Of course, a slightly different look than the original (which was flat on top) - but looks appropriate to the style and age of the watch.

Not perfect, but I'm pretty happy with the crystal. Now I just need to get it redialed. It appears to have be refinished in the past - and apparently with inferior materials. As you can see how bad this dial looks now (can best be seen in the pics posted above).

I want Dial Craft (Ontario Canada) to do the work - but they are shut down for the COVID-19 pandemic and apparently not opening anytime soon. I will probably still wait for them unless I can find someone open for business that I trust.

Does anyone here have any recommendation for dial refinishing?

I believe that International Dial Company was well thought of years ago - but seems like they have been on pretty sketchy ground for the last several years - and the examples that they show on their web site look pretty bad to me. Presumably the ones pictured are their better/best work. So, I don't think I would send them anything in the near future (if ever). 

-Paul

[Klassiker]

Very neat work indeed! Sets the watch off a treat.