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CR39 Or Polycarbonate? Your glasses?

Discussion in 'Shooting Related Threads' started by WoodsonEnt, Oct 2, 2010.

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  1. WoodsonEnt

    WoodsonEnt Active Member

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    Does your shooting glasses have CR39 or Polycarbonate lenses? Can you tell any difference in clarity if you have tried both?
     
  2. mixer

    mixer Well-Known Member

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    Here you go, everything you ever wanted to know about CR39-vs Polycarbonate.

    "CR-39 refers to the material that is used to make the majority prescription lenses. It is an optical grade plastic polymer recognised for its light weight, chemical resistance properties and 'tint-ability'. In comparable prescriptions it is approximately half the weight of glass lenses, while being slightly thicker. Its impact resistance is greater than glass but does not rise to the level of polycarbonate and it should not be considered for applications where impacts are prevalent. On this basis, it is not recommended for active sports and motorcycling. It is more scratch resistant than polycarbonate, but will scratch if not properly taken care of.

    Polycarbonate is an impact resistant material. It is becoming used more widely in recent times - especially for motorcycling and action sports. It is also used frequently for the glazing of rimless frames because of these properties. Although polycarbonate is impact resistant, it should not be considered indestructible. Polycarbonate is the strongest material available and will have the tendency to break into larger pieces, instead of the CR39's smaller pieces, and is, consequently, less hazardous. Polycarbonate is thinner than standard CR39.

    Polycarbonate lenses are ten times more impact resistant than other plastics making them highly suitable for action sports or folk that are a little (shall we say) heavy-handed! They offer UV protection and stop 99.9% of rays from the sun, fluorescent lights and computer screens. Polycarbonate lenses can be supplied with a scratch resistant coating and are thinner than standard lens and therefore more comfortable to wear.

    Comparison of Lens Materials & Material Characteristics

    Polycarbonate

    - Strongest material for impact resistance
    - Lightweight
    - Can be coated for scratch resistance
    - Most have built-in UV radiation protection

    Plastic (CR39)

    - About one-half the weight of glass
    - Resistant to solvents and pitting
    - More choices for coatings and tinting"


    Eric
     
  3. Unknown1

    Unknown1 Well-Known Member

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    I've had all 3 materials. You didn't say whether you needed prescription lenses; it can make a difference in your selection.

    The optical qualities of CR-39 are generally better than those of polycarb and it's easier to work with and tint.

    CR-39 can also have scratch-resistant coatings applied and UV protection applied.

    Trivex is better optically than both of them; it's lighter and more rigid which makes it the best choice for frameless lenses.

    MK
     
  4. 320090T

    320090T Well-Known Member

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    I talked with Della at the Grand and she said to go with CR39 over polycarb. She should know.
     
  5. Easystreet

    Easystreet Well-Known Member

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    Rather than letting someone else make the decision for you, why not just describe the properties of both materials and let each individual decide for himself what's best? Some shooters might decide that having 10 times more shatter resistance in the polycarb lens is worth the small sacrifice in optical quality as compared to the CR-39 lens. Other shooters may not care much about the safety feature and figure that the CR-39 lens is safe enough.

    In my opinion, ANY lens is "safe enough"......... until you actually need it to protect your eyes. I'm pretty sure that the slight optical advantage of the CR-39 lens is not going to make me a world champion, and probably not even a club champion. Therefore, I'm going to choose the lens that will best protect my eyes since it's the only pair (of eyes) that I'll ever have.

    Easystreet
     
  6. WoodsonEnt

    WoodsonEnt Active Member

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    When I was dealing the Decot line, they pushed CR39 for optical clarity. I am just looking for opinions from those who tried or have both.
     
  7. Unknown1

    Unknown1 Well-Known Member

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    <blockquote><I>" I'm pretty sure that the slight optical advantage of the CR-39 lens is not going to make me a world champion, and probably not even a club champion. Therefore, I'm going to choose the lens that will best protect my eyes since it's the only pair (of eyes) that I'll ever have."</I></blockquote>

    Your reasoning is sound but your facts are a bit shaky. While the optical advantage of CR-39 may not make you a champion, it can prevent shooting from turning into a miserable experience. Polycarb lenses are prone to optical aberrations; they can distort light transmission and introduce all manner strangeness into the visual information you get to process.

    I used to shoot with a guy who would occasionally go home sick from the range. We all blamed it on his stomach and the food at the club. This happened for more than a year until an optometrist joined the club and happened to notice the guys glasses sitting on a table in the sun. He remarked about the distortion in the lenses and suggested that the shooter might want to try a pair made of a different material. The guy had a new pair of lenses made of Trivex which has the same impact resistance and UV protection of polycarb, better optical qualities and lighter weight. In the end, the sick days stopped and the scores went up.

    MK
     
  8. spitter

    spitter Well-Known Member TS Supporters

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    Trivex is the best for clarity and impact resistance, but you'll pay a premium for the material. Of the two standard materials, the average Joe has to make a concession.

    For impact resistance between CR39 plastic and Polycarb there is no contest... polycarb is superior and offers 100% UV protection.

    For optical clarity and tintability - CR39 is the winner.

    If you have "plano" customers, for your own liability, recommend the protection
    from polycarb. If you customers want Rx and/or special colors, make sure you give them enough information to make an informed choice...

    Jay
     
  9. Easystreet

    Easystreet Well-Known Member

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    If a guy had a problem with ONE brand of shotgun, would you condemn all shotguns of that brand? Occasional problems can occur with ANY brand of product or any type of material. If a steel shotgun barrel blows up, does that mean that all steel barrels are no good?

    There have got to be millions of people who wear polycarbonate lenses every day in either their shooting glasses, safety work glasses, or regular street glasses. Does one guy who ALLEGEDLY got sick from wearing polycarbonate glasses mean that polycarbonate is no good for shooting glasses?
     
  10. Texshooter

    Texshooter Member

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    I pay extra for Trivex because I CAN tell the difference. I am unusually sensitive to chromatic aberration; where the lens splits the light like a prism into different colors because of the refractive index of the material and gives objects a distorted apperance. My problem now is what intra-ocular lens replacement to go to when I have my cataracts operated on? AJ
     
  11. Unknown1

    Unknown1 Well-Known Member

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    Easy,

    For optical use, polycarb never was the greatest stuff for lenses and now it's obsolete technology:<UL><LI>Fact: Injection molded polycarb is prone to optical distortion.<LI>Fact: Depending on who molds it, the distortion can be bad.<LI>Fact: It bothers some people more than it bothers others.<LI>Fact: I know someone who it bothered so badly that it made him sick.</UL>I've had to look through polycarb since it was introduced: I've worn helmet and face shields made of the stuff that were so badly distorted I couldn't use them; I used similar shields that were clear. I've thrown away new Lexan safety goggles because I couldn't trust what I saw through them while the next pair were fine. There's good and there's horrid, but would I take a chance on using polycarb for glasses when I have a choice of better stuff that has no distortion problems. Not a chance! That wouldn't be a practical decision!

    MK
     
  12. Easystreet

    Easystreet Well-Known Member

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    "Fact: Injection molded polycarb is prone to optical distortion."

    ANY material, even clear air, can have optical distortion..... sometimes. Just because something "can" have a certain defect doesn't mean that it necessarily does.

    "Fact: Depending on who molds it, the distortion can be bad."

    The other side of that statement is... Depending on who molds it, it may have no detectable distortion at all. If the lenses have distortion, don't use them regardless of what material they are made of.

    "Fact: It bothers some people more than it bothers others."

    Here's another FACT. The overwhelming majority of people are not bothered at all.

    "Fact: I know someone who it bothered so badly that it made him sick."

    Here's another FACT. I know hundreds of people who have never gotten sick from
    wearing polycarbonate lenses. I once got sick from eating bananas. Should everyone avoid eating bananas because they made me sick one time?
     
  13. Unknown1

    Unknown1 Well-Known Member

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    Whatever you say, Easy... whatever you say.

    MK
     
  14. neofight

    neofight TS Member

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    I recently got a pair of shooting glasses(my first)and i ordered the trivex after reading as much on the subject as i could without going completely bonkers. I paid $35.00 extra for Trivex over polycarbonate. I like the light weight and they seem to have little, if any, distortion.
     
  15. neofight

    neofight TS Member

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    I recently got a pair of shooting glasses(my first)and i ordered the trivex after reading as much on the subject as i could without going completely bonkers. I paid $35.00 extra for Trivex over polycarbonate. I like the light weight and they seem to have little, if any, distortion.
     
  16. neofight

    neofight TS Member

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    I recently got a pair of shooting glasses(my first)and i ordered the trivex after reading as much on the subject as i could without going completely bonkers. I paid $35.00 extra for Trivex over polycarbonate. I like the light weight and they seem to have little, if any, distortion.
     
  17. BigM-Perazzi

    BigM-Perazzi Well-Known Member

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    I've gone to the Pilla Ballistx material lenses. I've found their wraparounds give no distortion and give me a better overall view of the target.

    Jim
     
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