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Why don't tail lights cloud and oxidize?

Discussion in 'Fred's House of Pancakes' started by cyberpriusII, Sep 30, 2019.

  1. vvillovv

    vvillovv Senior Member

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    They do, you just can't see it most of the time ..... I especially like the tail lights wtih the pealing red tape showing the white 12v bulb in it's socket.

    Just think eyeglasses and the special UV and other coatings available that they insist on adding to the plastic lens.

    If we drove in reverse most of the time the tail lights would get most of the road debris.
     
    #21 vvillovv, Oct 2, 2019
    Last edited: Oct 2, 2019
  2. The Electric Me

    The Electric Me Go Speed Go!

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    I sat in the parking lot during lunch yesterday and looked at all the different vehicles, thought of this thread and came to the conclusion that I could very well be totally wrong with my speculation.
    I kill a lot of time coming to the conclusion that I might be totally wrong.

    Looking at all the different tail light designs, it seemed to me they got as much exposure as headlights.

    So maybe the answer isn't as simple as directional or placement exposure differences.

    To add, automakers have to be aware that this is a problem.
    Hard for me to believe a slight upgrade in materials couldn't go a long way to preventing or reducing this happening.
    Sad to think they would rather manufacturer cheaper, and possibly sell you a new headlight assembly later.
    Some UV light, fade resistant possibility has to exist.

    Yep, I remember when headlights were glass.
    I don't think it's a viable answer today. But you didn't worry about those headlights getting cataracts.
     
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  3. ETC(SS)

    ETC(SS) The OTHER One Percenter.....

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    My faithful 06 Envoy is starting to show some signs of age-related illnesses like cataracts.
    I thought about buying one of these $20 kits and spending an afternoon buffing out the old ones and them I got curious and priced out some replacements which seem to run in the $100-$200 range for a set.

    My last set of tires were a little (lot) more expensive than that, and they didn't last nearly as long!!!

    Face it.
    Headlamp assemblies are now a wear item for cars like shocks and struts, batteries, brakes, etc....and this is not new at all.
    Back in the "good old days" headlamps came in two basic shapes (round/square) and they were often replaced when the bulb filament went out, or they got broken by gravel since they were usually oriented vertically instead of slanted for aerodynamics- so often as not they never lasted long enough to GET cataracts.
     
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  4. alanclarkeau

    alanclarkeau Senior Member

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    I've been looking too - and I'm seeing lots more tail-lights which aren't shiny/glossy any more - but doesn't seem to be affecting the luminosity, like with headlights.
     
  5. Leadfoot J. McCoalroller

    Leadfoot J. McCoalroller Senior Member

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    Side and tail lamps are more likely to be polymethyl methacrylate, which isn’t as sensitive to UV.

    It is more brittle and shatters more easily than polycarbonate. So there is some logic in putting the PC parts on the front of the vehicle and PMMA elsewhere.
     
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  6. Trollbait

    Trollbait It's a D&D thing

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    UV filters are applied to polycarbonate for headlights and a lot of other products(eye glasses, bottles, etc.); naked PC does not stand up to UV well at all.

    If there is a regulation stating how well headlights resist 'cataracts', the car companies are only going to do the bare minimum. Then there are technical issues that may prevent making them more resistant. The treatments will have an impact on the light passing through them. Visible blue light could be filtered out, or they reduce the total amount of light, requiring brighter bulbs.

    The lights have two different jobs.

    Headlights are used to light up an area for vision. When that area gets smaller or dimmer, it is noticed.

    Taillights aren't for helping vision, but to be seen. As long as they can be seen when turned on, it doesn't really matter much how well they illuminate the surrounding area.

    Then there are factors like cloudiness being less obvious on the colors and textures of taillights compared to the relatively huge area of crystal clear headlight lens, and that the only time you might notice your taillight is when the bulb is out, and even that could go unnoticed.
     
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  7. Mendel Leisk

    Mendel Leisk Senior Member

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    I'd love to see Ralph Nader type legislation, to mandate that headlights be practical designs, with easily and cheaply replaceable lens. Something the owner could do, for less than $50, for both sides.
     
  8. Leadfoot J. McCoalroller

    Leadfoot J. McCoalroller Senior Member

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    We already had that, it was called 1968-1985.

    Once Ford got their exemption for the aero polycarbonate lenses on the ’86 Taurus it all went downhill.
     
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  9. ice9

    ice9 Active Member

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    Why do headlights fog up more quickly than tail lights? Part of it is due to dust, sand and flying debris.

    I.e. The same reason why it always rains harder when you're driving on the interstate.
     
  10. ChapmanF

    ChapmanF Senior Member

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    The stuff I'm using must be more like the stuff Kris is using (though mine is Turtle Wax brand). It just came in a bottle and cost a few bucks, and it isn't a kit, and doesn't take anything like an afternoon to apply, maybe ten minutes with a rag, and at the rate I'm using it up, my heirs will inherit the bottle.

    Has to be re-done at least once a year, and I'd probably do twice if I had a lower threshold of embarrassment over cloudy headlights. But it's a small enough amount of work that so far I haven't been tempted to do anything more elaborate.
     
  11. vvillovv

    vvillovv Senior Member

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    If I were into bettin I'd bet the turtle wax headlight restorer will work semi well on eye glasses with crimkled coating(s). Although if would probably have to be reapplied more often than once a year.

    My 02 civic has badly yellowed headlight lens. I took the buffer to them both last summer when I had them removed from the car. It helped a bit, but the old 9003 Halogens just don't lightup the road ahead as well as the newer projectors or LEDs or it could be the original 17 year old gettin weak 12volt. ymmv
     
  12. alanclarkeau

    alanclarkeau Senior Member

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    Yep - but only in USA (Canada??) - ours looked like the bottom ones, and had DRLs:
    upload_2019-10-4_13-8-28.png
     
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  13. meeder

    meeder Active Member

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    The reason you have to repeat it every year is because with the first time you polished off the protective coating completely.
    If you polish the headlights and apply a new coating it will last a lot longer.
     
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  14. ChapmanF

    ChapmanF Senior Member

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    At less than 10 minutes each year just to do this, how many years would it take to break even with polishing and re-clearcoating the lenses?
     
  15. Sharnold

    Sharnold Active Member

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    I've been wet sanding the oxidized headlights with 1200 grit then using alcohol to clean the surface then use a buffer with a plastic buffing compound I buy off Amazon. Problem solved. And never use paint thinner it will eat the plastic and you'll be starting over again.

    Posted via the PriusChat mobile app.
     
  16. The Electric Me

    The Electric Me Go Speed Go!

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    I can buy garbage bags that are scented to smell like fresh linen or tropical rain forests.
    Why can't they make a headlight that stays clear for the life of the vehicle?

    Don't answer that, I'm going to go smell the rain forest.
     
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  17. Trollbait

    Trollbait It's a D&D thing

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    By the car maker's tally, they do stay clear for the life of the car.;)
     
  18. The Electric Me

    The Electric Me Go Speed Go!

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    I'm willing to believe any manufacturers claims if it makes me feel better.
    My toothpaste say's it repairs and restores tooth enamel.
    My dentist tells me once enamel is damaged and gone? It doesn't grow back or repair itself.

    One of the two claims is less than truthful or the full picture.
    Regardless, I buy the toothpaste that supposedly repairs my teeth.

    I'd be happy if a car manufacturer or headlight assembly manufacturer claimed the headlight was invulnerable-highly resistant to fade or clouding.

    PS.
    My garbage can does smell like a tropical rain forest...in which a lot of garbage has been dumped.
     
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  19. Paul Schenck

    Paul Schenck Active Member

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    How about the head lamps produce UV A and B as well as the sun it does not pass through plastic as it does glass. So the headlamps are exposed to twice the UV because the tail light are not high intensity.

    Just an old opticians point of view.
    Thanks for the post good question


    iPhone ?
     
  20. Trollbait

    Trollbait It's a D&D thing

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    From quick googling it seems halogen and HID bulbs should have their own coating to filter out any UV they produce. LEDs emit very little, and it sounds like they work like fluorescents, the UV they make is converted to white light.

    Then the various fixes for the cataracts are only applied to the outside, and they do clear it up.
     
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