need advice for plugging drilled holes

Discussion in 'Camera Building, Repairs & Modification' started by David Lyga, Jun 5, 2012.

  1. David Lyga

    David Lyga Subscriber

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    Sometimes the ONLY way I can get the circular nameplate off the front of a lens (for cleaning and removing helical grease from old lenses) is to drill tiny holes, 180 degrees apart, on that circular nameplate around the front element. It's risky and demands precision but it can be done. This is done after using wads of tape and a scissors to try to unscrew the disk manually.

    What can be put into the holes to make it look like no drilling was done or, at least to mitigate the visual effect? It really does not matter what color the substance is because after it dries I could paint it black. I need info for both plastic and metal circular nameplate disks. Thanks. - David Lyga
     
  2. Ian Grant

    Ian Grant Subscriber

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    I use black acrylic paints for many purposes, they vary in terms of the finish, some are more glossy others quite matt. Over the past 3-4 years I've tried about 7 or 8 different ones and have two I particulary like, one a slight gloss the other matt. Flexibility differs as well.

    As they are water based it's easy to wipe off excess until they dry.

    Ian
     
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  3. David Lyga

    David Lyga Subscriber

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    Good, Ian, and I even have some. It comes in a tube and is very thick (low viscosity). I will try this. Thank you. - David Lyga
     
  4. steven_e007

    steven_e007 Member

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    Are you really sure it is absolutely impossible to remove the ring without holes?

    Personally I haven't yet found it necessary.

    In extremis I have in the past resorted to heating the whole lens in an oven (a cool oven, obviously... gentle heat!) and then using freezing spray or ice to cool the ring (I cover the glass with a rubber disk and a cloth to protect it).

    For grip a rubber bung of just the right size usually helps. (Laboratory suppliers on eBay!) Most bungs are quite hard rubber - which often works, but can slip. for better grip a circle of softer latex over the bung gives more grip. (I bought some latex 'exercise bands'. They are just latex ribbons). In a few cases I have resorted to hot gluing something to the rim, too.

    Vibration also helps. Sometimes trying to tighten it first, before removing, works as well.


    The only total failure I've had is with a 1930s Aldis lens where an aluminium ring had cold welded into an aluminium casting. I read somewhere (maybe here on APUG?) that aluminium can't actually cold weld under these conditions, it is a myth. Myth or not - it was totally ***** stuck! In my desperation I actually splintered the ring - although about 2/3rds of it remained 'welded' in place, leaving me with a scrap, unrepairable lens. :sad:
     
  5. David Lyga

    David Lyga Subscriber

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    Yes, I use drilling ONLY as a last resort. When deep rust has set in that is sometimes the ONLY way to do this. What I find especially annoying is that with some lenses the ring does not have threads (the whole front piece, sides and ring together, screw off) or even pops off (Canon 1.8/50mm FD). It becomes difficult to understand how one should go about removing the front in those cases. - David Lyga
     
  6. ic-racer

    ic-racer Member

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    Try heat on stubborn rings. I heat lenses on a print dryer so they are too hot to handle without rubber gloves. Once it is hot, then I go after the ring. I have never had to resort to anything that severe as drilling holes in the ring and I have disassembled many, many lenses. Never had glass break either. Heat and cool slowly.

    I filled screw holes on the back of my 8x10 enlarger with these tiny plastic push-rivets: http://www.efc-intl.com/products/pa...ets-plastic-push-pin-mini-wpolished-heads.htm

    I suspect those may be too large, you might try this black plastic stock used to make marker dots if it fits in the hole: http://www.stewmac.com/shop/Binding..._Dot_Material.html?actn=100101&xst=3&xsr=1680
     
    Last edited by a moderator: Jun 6, 2012