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Thread: Help needed: cleaning lens from firecracker particles

  1. #1
    cyberjunkie's Avatar
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    Help needed: cleaning lens from firecracker particles

    Please let me know if you have any "secret recipe" for stubborn dirt.
    Recently i acquired a recent multicoated lens. It is damaged and it was priced accordingly.
    The seller told me that the front glass was damaged by a firecracker, which exploded close to the camera on New Year eve.
    From the pictures i thought that it was impact damage, some small dots caused by tiny objects hitting the lens at high speed.
    When i had the lens in my hands i realized that there is no missing material. The small dots are in relief!
    I think that during the explosion of the firecracker, some molten particles hit the glass and got stuck to it!
    At close inspection the dots look glass-like. Nothing comes out if scratched with a nail.
    Normally i use isopropilic alcohol or ROR. I am not at home, and i don't have them at hand, but i gave the lens to a friend of mine, who will try with the alcohol and with a commercial lens cleaner.
    I am almost sure that it won't be enough. Before trying to pry off the particles with warmth (hair dryer), i'm trying my luck on this forum. Maybe some member has an idea that could work...
    Somebody gave me the advice to use WD-40 or Svitol (a locally made oily spray, used to loosen rusted screws), but i'm not sure it won't affect the modern multi coating.

    I will try any suggested solvent ... the only limitation: it must not eat the coating.

    ciao

    Paolo
    have fun
    CJ

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  2. #2

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    Re: Help needed: cleaning lens from firecracker particles

    Quote Originally Posted by cyberjunkie View Post
    ...The small dots are in relief!
    I think that during the explosion of the firecracker, some molten particles hit the glass and got stuck to it!
    At close inspection the dots look glass-like. Nothing comes out if scratched with a nail......
    I suspect that is exactly right. I have had glass damaged by welding sparks, and the only way I could minimize this damage was to gently scrape off the particle. I used a 10x microscope and a very sharp and smooth exacto knife blade. Good luck!

  3. #3

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    Re: Help needed: cleaning lens from firecracker particles

    Quote Originally Posted by resummerfield View Post
    I suspect that is exactly right. I have had glass damaged by welding sparks, and the only way I could minimize this damage was to gently scrape off the particle. I used a 10x microscope and a very sharp and smooth exacto knife blade. Good luck!
    Did it make a difference? I would think that just leaving the sleeping dog lie would be the more prudent thing to do.

  4. #4
    jp's Avatar
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    Re: Help needed: cleaning lens from firecracker particles

    If you're at a point with nothing to loose, I'd try a car cleaning "clay kit". They remove stubborn stuff by particles sticking to the clay. Chances are good if the small dots are dark, they will not affect the image and could be left alone. try shooting with it.

  5. #5

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    Re: Help needed: cleaning lens from firecracker particles

    Like Brian said, Leave it alone. Most folks are WAY to obsessed with dirty lenses or defects which won't make an appearance on film. In this case, it sounds like anything you do may remove the particles and/or multicoating, but leave holes behind.

  6. #6

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    Re: Help needed: cleaning lens from firecracker particles

    If it's melted to the glass wouldn't removing it remove the coating?

    I'm with Brian and Vinny on this one. Try shooting it as is and see what your results are before messing with it.

  7. #7

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    Re: Help needed: cleaning lens from firecracker particles

    I would wait and use ROR. When you do, do not use a lot of force. Let the cleaner melt the particles free and carefully "mop" them away.

  8. #8
    cyberjunkie's Avatar
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    Re: Help needed: cleaning lens from firecracker particles

    If the particles were dark, i would leave them alone. They are glass-like, and behave as small crazy lentils scattering the light around. It makes a difference. Plenty of it.
    While we were examining the damage, a friend told me that an old 55mm Micro Nikkor was damaged by a child with a screwdriver blade. Lots of scratches. After that the lens was still performing very well, taking wonderful detailed pictures!
    Not all damages are alike. Unfortunately in this case the performance of the lens is definitely affected.
    As a last resort, if i can't clean the spots, or find a replacement front glass, i will blacken the affected areas with china ink, and see how it works.... but i hope to find a way to melt (or pry off) the particles glued to the glass.

    cheers

    Paolo
    have fun
    CJ

    WTB (and pay good monet for):
    soft back cell for Ilex Photoplastic 5x7
    disks for Imagon 420mm
    5x7 back for Calumet C1
    5x7 conversion for Bi-System

    for sale
    Photographica

  9. #9

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    Re: Help needed: cleaning lens from firecracker particles

    Quote Originally Posted by cyberjunkie View Post
    If the particles were dark, i would leave them alone. They are glass-like, and behave as small crazy lentils scattering the light around. It makes a difference. Plenty of it.
    Paolo
    Paolo,

    A possible solution is to use opaque black paint to cover the small bead-like particles, thus preventing them from scattering light. It was/still is common practice to black out a scratch in a lens for exactly the same reason.

    Even if you manage to get the particles off the lens, you may still end up with defects in the glass or coating that may require blacking out.

    Best,

    Doremus

  10. #10

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    Re: Help needed: cleaning lens from firecracker particles

    Hoppe's nitro powder solvent is what gun owners use to loosen similar stuff. Might be worth a try.

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