Jump to content

Crystal Polishing?

mcass

By mcass
in Watch Repairs Help & Advice

 Share

Recommended Posts

mcass WRT Addict

mcass

Posted
Posted

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?

Link to comment
Share on other sites
JimInOz WRT Addict

JimInOz

Posted
Posted

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.

Link to comment
Share on other sites
Endeavor Distinguished Member

Endeavor

Posted
Posted (edited)

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
Link to comment
Share on other sites
JimInOz WRT Addict

JimInOz

Posted
Posted

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). 

Link to comment
Share on other sites
Endeavor Distinguished Member

Endeavor

Posted
Posted (edited)

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.........

Edited by Endeavor
Link to comment
Share on other sites
stroppy WRT Addict

stroppy

Posted
Posted (edited)

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
Link to comment
Share on other sites
mcass WRT Addict

mcass

Posted
  • Author
Posted

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?

Link to comment
Share on other sites
 Share
Go to topic listing


  • Recently Browsing

    • No registered users viewing this page.

  • Topics

  • Posts

    • ManSkirtBrew
      1972 Bulova President "E" Sea King 11ACACB movement

      By ManSkirtBrew · Posted

      Oh nice. I have a similar wedge style stump for my staking tool, so I'll give that a shot. Thanks!
    • joelcarvajal
      Gamblin Gamsol for cleaning?

      By joelcarvajal · Posted

      Thank you all for the replies!  Very informative! True enough, the Gamsol took some time to evaporate and does leave a residue. So not all naphtha are created equal!  Need to find alternatives then. i was able to try Hexane recommended by Alex and it seems great.  I wonder what the cons are?
    • GuyMontag
      1972 Bulova President "E" Sea King 11ACACB movement

      By GuyMontag · Posted

      Yeah, I saw that in the tech sheet but I don't see how it can be adequately cleaned with the friction pinion still in place. I've accidentally pulled the arbor right out of the wheel once when I used a presto tool to try and remove it. Mark shows how he does it with the Platax tool. Those are a little too pricey for me so I got one of these from Aliexpress and I just push down on the arbor with the end of my brass tweezers. That usually gets it most of the way out and then I just grab the wheel with one hand the and the friction pinion with the other and gently rotate them until it pops off. Probably not the best way but it's seemed to work for me so far.    
    • Zedster
      Movement inserted from crytal side

      By Zedster · Posted

      Thanks, Jon Sounds like a plan. Obviously I'll have the face on so do you think gripping with the holder will create any problems, but I will check in the morning to see how feasible it is but I assume it only needs to be lightly held. As for holding the movement instead of the holder won't be possible in this scenario as one hand will be puling on the stem while the other pushes the spring down. That was my initial concern is how the hell can I do this with only one pair of hands. All the other times I've had to remove the stem hasn't been a problem, apart from the force required to release the stem from the setting lever, but now I need to fit the face and hands its sent me into panic mode. If it had the screw type release things would be a lot simpler but that's life 😀   Another thing I will need to consider is once the dial and hands are fitted and the movement is sitting in the case I will need to turn it over to put the case screws in. I saw a vid on Wristwatch revival where he lightly fitted the crystal and bezel so he could turn it over, is this the only option or is there another method?      
    • nevenbekriev
      Main spring

      By nevenbekriev · Posted

      Hi Jon, do You think that relation spring torque - amplitude is linear? I would rather guess that the amplitude should be proportional to the square of the torque. I had once idea to check it, but still haven't.
×
×
  • Create New...