• judooochp@lemmy.world
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    3 months ago

    I recently asked about having my coating re-applied, and the folks at the eye place had a warranty system, where if it came off inside of two years, they’d strip and re-coat the lenses. Might call them to find out if you’re covered, or of they can tell you the stripping method.

    • yokonzo@lemmy.worldOP
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      3 months ago

      Nah they’re glass, besides, I tested acetone on a small spot and it did nothing to remove the coating

  • j4k3@lemmy.world
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    3 months ago

    If it is anything like the polycarbonate lenses on cars, it will take extremely tedious polishing, and then you’ll have continuous issues with yellowing because polycarbonate is not UV stable.

    With my auto body shop, I sanded the lenses to 2000 grit and used a polyurethane clearcoat. However, typical automotive clearcoats are not optically perfect. It does not matter with an automotive headlamp, and 99.9% of people will never see the optical properties unless I pointed them out specifically. That said, coatings like automotive clearcoats are designed to adhere to very specific types of substrates. What I was doing was WAY outside of the intended use. I doubt any of the lenses I clearcoated lasted more than 3-5 years as a result.

    The PITA part of clearing lenses like I was doing with headlights is that ALL of the old coating must be removed first. If I didn’t sand off every last bit of that coating, it was very noticeable in the final outcome. I had some tricks, but it is not possible to use course grades of sandpaper that would make fast work of it situation but require a primer to level in a typical body shop situation. This meant I had to start with 1k grit. That takes FOREVER to sand through a coating like what headlamps have.

    Sanding anything like this is not compatible with optical precision lenses. I have also played with telescopes and building my own eyepieces while also dreaming about grinding my own mirror for a large dob. Optical precision in lenses is OP insane levels. I don’t have the vocabulary to express just how tiny the difference is between good, okay, and absolute trash in optics.

    Combining my experiences in these areas, there is absolutely no chance that you’ll be able to polish or abrade then polish an optical lens and yield an acceptable outcome. No matter what you try, the coating will abrade/polish at a different rate than the exposed sections of the underlying polycarbonate lens. This will always result in an uneven surface at optical quality kinds of levels. You would need a sanding block capable of matching the contour of the lens perfectly so as to only abrade away the coating section before contacting the lens.

    While clearing headlamps, I had one of two tricks. If all I was doing is shooting the lenses, I would mix my clear without any additional reducer (special solvent) and with a fast catalyst. This required special gun settings and higher pressures to avoid orange peal textures. If I was mixing clear for other panel work, I had to do a few misting passes with clear in between my other panel work. The thin misted coating limits the exposure of the underlying polycarbonate to the solvent present in the clear. If I did a regular wet pass like I would with a panel, the lens would react to the solvent and looked like a shattered windshield.

    I don’t know of anyone else that has ever clearcoated headlamps like this. While my work may not have lasted as long as a typical clear, it was a far better solution than polishing, which reoxidizes within a few weeks and worse with the increased exposed surface area after each polishing. For higher end cars, dealers would just pay me to install reproduction headlamps from LKQ, as these will last like the originals or better.

    Those are the basics of what I know. I shared as an abstract way to help you understand the scope of what I know, and what you should expect based on this tangentially related expertise. I do not believe you can be successful at removing that coating. In automotive paint, it is not possible to just remove a clearcoat from any surface chemically without impacting the deeper substrate.

  • Shdwdrgn@mander.xyz
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    3 months ago

    Just an FYI, I had that happen to my driving glasses a couple years back. My optometrist said that’s because you cannot leave glasses in a hot car as the heat destroys the coating… OK thanks for telling me AFTER the fact, where do you THINK I am keeping a pair of glasses that you designed specifically for my driving vision? And by the way, I’ve been wearing glasses for over 35 years and always had the anti-glare coating for night driving, what did you change that is suddenly making them self-destruct when they are stored where I need them???

    Yeah they had no answers for me. But OP, if you left your glasses in your car, that’s probably what happened to the coating.

    • pearsaltchocolatebar@discuss.online
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      3 months ago

      Just an FYI, temperatures in a car in direct sunlight can exceed 165F. Very quickly.

      I know this because I left a glass thermometer under my seat for an hour one summer. When I came back to grab it, the glass has burst (max on the scale was 165F).

      I have no idea about lens coating changes over time and their heat tolerance, but the insides of cars can be fucking awful.

      • Shdwdrgn@mander.xyz
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        3 months ago

        Oh I agree it can be a friggin’ furnace. My complaint was that I’d never had that happen before so why is it happening now? And if I can’t keep my driving glasses in my vehicle, where am I supposed to keep them? Maybe keep them at my desk just in case my monitor suddenly gets really far away?

    • yokonzo@lemmy.worldOP
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      3 months ago

      No but I did take a trip to the deep south, Kentucky is a killer this time of year

  • ReallyZen@lemmy.ml
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    3 months ago

    Next time ask your lenses without. Mines are the same, I have a new prescription & just told the shop “no”. No anti-blue, no ant-reflection, no nothing, just the hardest material available.

    • over_clox@lemmy.world
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      3 months ago

      Unfortunately that wasn’t an option at Walmart the last time I got glasses. I wanted to go to my old eye doctor instead of Walmart, but that was during the COVID lockdown shit and I would have had to wait like 3 months.

      Sigh, this coating shit sucks ☹️

      • ReallyZen@lemmy.ml
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        3 months ago

        Yes, a catastrophy. I never had lenses degrade so fast, and we’re talking expensive Zeiss stuff with medical coverage.

        That was my first “no” here, never again.

      • LouNeko@lemmy.world
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        3 months ago

        Ah, that sucks, I’d suggest to get some of the shelve as an emergency solution, but I know some countries don’t sell negative diopter lenses without a prescription. The issue is that polishing out those scratches even if it’s just the coating can change the lenses diopter value even by a tiny amount. This can lead to distortions or blurriness even if it looks perfectly smooth. Ask around some opticians, maybe they have a cheaper plastic replacement lenses or they can polish them out professionally for a fee. I know this sucks but I wouldn’t mess around with this on my own, it can damage your eyes in the long run.

  • Alteon@lemmy.world
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    3 months ago

    You fix it pretty easily by just getting the lenses entirely replaced. If you have vision insurance, you can do it entirely for free

    • yokonzo@lemmy.worldOP
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      3 months ago

      Does someone willing to strip off the coating of their glasses sound to you like someone who has vision that allows for more than one pair of glasses a year?

    • yokonzo@lemmy.worldOP
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      3 months ago

      Oh well good thing it’s not breaking off into a powdery substance near my nose and mouth

        • SturgiesYrFase@lemmy.ml
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          3 months ago

          I mean, it might legit be more comfortable to wipe with a pinecone or stinging nettle. So take that humble brag as you will, but sometimes the grass isn’t cushier on the other cheek.

          • Anna@lemmy.ml
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            3 months ago

            You degenerate 3rd world people still using paper to smear poop all over yourself. We here in modern world have water that washes away our poop.

            • SturgiesYrFase@lemmy.ml
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              3 months ago

              Yeah, used to love bidets, then I sat down drunk and accidentally nudged it full blast full cold. The hemorrhoids I got the next day were brutal. So now I use tp cause the worst that can happen while drunk is I need to wash my hand a bit more thoroughly than usual…