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Crystal Polishing?

mcass

By mcass
in Watch Repairs Help & Advice

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mcass WRT Addict

mcass

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I am VERY new to watch repair. I have an M9 Bulova Oceanographer that had some very serious scratches and gouges in the crystal. At the suggestion of a friend, I used Flitz Metal Polish on it. Simply rubbing it over the crystal with my index finger in circular motions for literally about 8-10 hours across a two week time frame. The crystal is now gorgeous with no signs of scratches or other imperfections.

With my success doing this, I bought a 90's Seiko at a thrift shop for a couple of bucks that had some very serious scratches in it (not near as bad as the Bulova). I have tried the same thing on the Seiko for an hour or so and don't think it is doing a thing. Are crystals made of different materials? Can a Seiko crystal be polished?

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JimInOz WRT Addict

JimInOz

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Many vintage "crystals" are actually a plastic polymer resin or plexiglass, Omega has a plastic crystal material named Hesalite.

 

These can be polished quite easily with great results by simply using a very fine abrasive like Brasso.

 

Mineral crystals are the next step up and are much harder than plastic but can still be scratched. One advantage is that the aren't as brittle as sapphire crystals. Being softer than sapphire they can be polished more easily, but not as easily as plastic.

 

Sapphire crystals are hardest of the three and are hard to scratch (but not impossible) and are hard to polish without proper abrasives and tools.

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Endeavor Distinguished Member

Endeavor

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Hello Mcass & JiminOz;

I'm currently facing the same problem / question. I bought some diamond paste, different grit sizes from #600 down to #10.000 and attempted with a Proxxon, similar to a Dremel, and small felt-discs to polish a sapphire crystal. Started of with #1000, but that didn't seem to bring anything. With grit #600, slow progress is made, but the crystal gets quickly very hot. Obviously I try to spread the heat evenly over the crystal to avoid great stresses, and allow cooling periods, but progress is slow.

Edited by Endeavor
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JimInOz WRT Addict

JimInOz

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Unless your crystal is unobtainable then I'd just suggest a new crystal (even generic crystals may be suitable).

 

Far easier, and the risk with using buffing discs is dishing or ending up with an uneven surface. Ideally you would grind the crystal on a super flat plate (unless it was domed). 

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Endeavor Distinguished Member

Endeavor

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Very true that the sapphire crystal may/will not become flat. I started off on a flat mineral glass plate, manually, and unlike as "shown" on some YouTube video's, I wasn't getting anywhere.....that is to say, it was the mineral glass plate which got grinded :(

My first learning "casualty" sapphire crystal is from a cheap quartz watch, a watch not worth a new crystal.

Seems, to get a perfect job, you need one of those disc they use to polish diamonds? ($$$?)

To summarize; I had no real suc6 jet.........

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stroppy WRT Addict

stroppy

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I've experimented by making a paste of cerium oxide, a tiny drop of cooking oil and bicarb powder.  I also used a Dremel with a polishing disk.  First I ran the paste over the crystal, then used the Dremel for about thirty seconds.  Then you wait a minute or so for the crystal to cool and then repeat.  It takes some patience but it does make a difference on glass crystals.

Edited by stroppy
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mcass WRT Addict

mcass

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Unless your crystal is unobtainable then I'd just suggest a new crystal (even generic crystals may be suitable).

 

Far easier, and the risk with using buffing discs is dishing or ending up with an uneven surface. Ideally you would grind the crystal on a super flat plate (unless it was domed). 

Where can you get Seiko crystals and are they difficult to change out?

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