Installing oddball crystals

[HauteHippie]

The Franck Muller crystals are quite thin with a fairly good curvature to them and are obviously an oddball shape. Having just double AR coated one for a forum member I got to thinking... It seems like the regular press and die could be a little problematic with this crystal. Has anyone removed and reinstalled a FM crystal, and if so how'd you do it?

Thanks in advance.

[offshore]

Chief,

Haven't done an FM, but have done quite a few Oblong and "fancy" shapes.

I take it we are talking acrylic here!! ( If it's mineral glass or saphire, it would be original and must fit!)

First, check that it doesn't just fit with finger pressure. If it does, some GS Hypo cement, which is more like a gasket will work.

The real trick is to make sure you have totally cleaned inside the bezel area.... all the old UV glue or cement, soak the case (only) in acetone if need be. Then use a screwdriver to clean up so you have a nice clean & flat area.

Now check the crystal, it should pop in with finger pressure.

If it is a new crystal (not previously fitted), mic the bezel and the crystal, and check how close it is to fitting.

You will then have to lightly sand the crystal to fit! Also use some fine rouge to finally polish the crystals' edges.

Then some Hypo or UV cure cement, pop in the crystal...done.

Offshore

[HauteHippie]

Yea, this would be a sapphire crystal. My first instinct would be finger pressure and GS Hypo gasket as you mention... But I'd be concerned about breaking it if it was a tight fit. The crystal is very thin...

[offshore]

chief,

Sapphire into its previous case should really just pop in. (support the underside with your thumb if you have any worries)

If it does feel at all tight, obviously don't force it.The other trick is to heat the casing, making it expand, and the crystal will "fall" in! Normally 80F-90F (hot -but not to burn fingers) And if there are any questions in your mind, still go with a gasket glue as a backup.

Offshore