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Thread: Polishing out a scratch!

  1. #1

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    Polishing out a scratch!

    Caveat: this is information only and refers to modern glass. Make of it what you will.

    My wife and I take underwater photos. My wife's dome port, made from a relatively hard mineral glass according to the manufacturer, got scratched last year (Scottish granite I suspect!) - a little under 1cm long and easily felt with a finger nail, peripheral scratches/scrapes too. I decided that rather than leave it as is, I would attempt to polish out the scratch myself. So armed with a Dremel fitted with a polishing felt tool and some jeweller's rouge I have been slowly, for short bursts, polishing the affected area. So far some of the peripheral damage has gone. The main damage is reducing but very slowly. I'm being extremely careful not to allow the area to heat up - if I can feel any warmth developing I stop and leave it for an hour. Differential heating of glass can shatter it - I had a professional firm try to polish a scratched dome port some years ago and it did shatter - they only undertook to try at my risk.

    What's my point? Well if an softer, uncoated lens has a significant scratch which causes problems then it might just be worth attempting to polish it out. Dome ports are simple lenses though and a relatively small area with a very slight difference in its curvature is unlikely to be problematic. I'll report when I've finished polishing the scratches out - may be a few weeks away - but it seems to be working so far.

  2. #2

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    Re: Polishing out a scratch!

    Quote Originally Posted by pgk View Post
    Caveat: this is information only and refers to modern glass. Make of it what you will.

    My wife and I take underwater photos. My wife's dome port, made from a relatively hard mineral glass according to the manufacturer, got scratched last year (Scottish granite I suspect!) - a little under 1cm long and easily felt with a finger nail, peripheral scratches/scrapes too. I decided that rather than leave it as is, I would attempt to polish out the scratch myself. So armed with a Dremel fitted with a polishing felt tool and some jeweller's rouge I have been slowly, for short bursts, polishing the affected area. So far some of the peripheral damage has gone. The main damage is reducing but very slowly. I'm being extremely careful not to allow the area to heat up - if I can feel any warmth developing I stop and leave it for an hour. Differential heating of glass can shatter it - I had a professional firm try to polish a scratched dome port some years ago and it did shatter - they only undertook to try at my risk.

    What's my point? Well if an softer, uncoated lens has a significant scratch which causes problems then it might just be worth attempting to polish it out.
    With a Dremel fitted with polishing felt? You mean, it's a cure to replace a scratch with a different than original curvature area much bigger than the scratch? You cannot be serious.

  3. #3

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    Re: Polishing out a scratch!

    Its common practice with acrylic domes! Alteration of a small area may not have much effect.

  4. #4

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    Re: Polishing out a scratch!

    Unfortunately, in this case one cannot use the same technique on modern lenses, as suggested.

  5. #5

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    Re: Polishing out a scratch!

    No, only on uncoated glass surfaces. As I said, make of it what you will. Polishing out small areas of scratches on acrylic domes has been undertaken for a long time and successfully too. Severe, deep scratches excepted.

  6. #6

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    Re: Polishing out a scratch!

    Without going into details of why one cannot compare the acrylic domes repair with a taking lens amateur polishing - have you already cured a lens from scratches with your polishing technique? (I mean - without ruining the lens, of course).
    Just to say that you would discover for yourself that the proposed cure is far worse than the illness to be cured.
    Last edited by Pfsor; 6-Apr-2019 at 08:23.

  7. #7

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    Re: Polishing out a scratch!

    Years ago acquired a lens at a bargain price because it had a deep scratch on the front element that did show up on the negative (I believe when I used the lens really stopped down, but it's been years so don't quote me on that). Used some clear auto scratch filler on it. You could still definitely see where the scratch was on the front element, but it did not show up on the negative any more.

  8. #8

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    Re: Polishing out a scratch!

    Indeed, that's well possible - similar effect you can get even by filling the scratch by black ink. It is however a different scenario than that of the OP. Still you make a correct point - it is better to fill the scratch with a filler rather than trying to polish it incorrectly.
    Last edited by Pfsor; 6-Apr-2019 at 08:18.

  9. #9
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    sin eater

  10. #10

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    Re: Polishing out a scratch!

    And what has that to do with the polishing technique discussed in this thread?

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