When did shellac stop being used as pallet jewel glue?

[Mk2]

I've been working on a "modern" era ETA with a broken fork (looks like someone decided to see why the balance doesn't completely rotate). One of the fork tines had been snapped off! And thought "what shall I do with this fork?". So i decided to remove the pivot and separate the jewels.

Out with the methylated spirit (to dissolve the shellac). So chucked the fork in a bucket of meths overnight, with the plan to separate them next day. Nope, didn't work. The shellac or whatever glue is as solid as ever... Clearly not shellac. Shellac dissolves easily with methylated spirit (and less so with IPA).

So, when did shellac stop being used as glue? And what do they use nowadays? Polyurethane adhesive? They stopped using radioactive radium metal particles mixed with zinc sulphide paste around 1970 as lume... Maybe around then?

 

[thesnark17]

Are you sure that the watch has not been bodged by a previous "repair person"?

Modern pallet fork jewels are still set with shellac by the big Swiss manufacturers, but some people have taken to using superglue instead when repairing.

 

[Mk2]

Yeah, absolutely positive the glue is original. Looks like shellac, you know, that brown or tan coloured ooze that sits around the edge of the jewel. But if it is shellac, why doesn't soaking it in an alcohol (ethanol) solution dissolve it? When ever i've used shellac as a glue or coating, meths works fine. So, my guess is that they either use a substitute or treat the cured and set pallet forks with a chemical or something? I just don't know. Even an oven bake won't stop shellac being dissolved. Unless they use a UV cure resin? That 'does' look like shellac...

Pre 80's pallet forks are so easily ruined by IPA, meths or similar alcohol based solvents, so something has changed. Just curious...

And don't get me started on cyanoacrylate (superglue). The vapours that coat everything nearby... The way it pulls in as it sets... The cracks and stress fractures that are setup as it cures... And it doesn't stick well to most metals, but just coats the surface. Really and totally should be kept well away from watches. So many better adhesive alternatives are out there. Modern chemistry is amazing. It's a shame I have little understanding of it.