Masks, How long is to long? Protection question... good Unka Phil Q

[Wes Janson]

Materials exposed to sunlight shall not undergo significant
loss of physical properties.

Newsflash: UV exposure weakens most forms of plastic, significantly. Try taking some cheap plastic toy and leaving it in the backyard for a week or two. It will first fade away entirely, and then become extremely brittle. Realistically, though, you would have to be leaving your mask on a windowsill for it to have a noticeable effect...but when it did, you likely would not enjoy the results.

and if you get bunkered to just check the lenz? No there can be stress cracks that you Can Not see.

If you put a mask on, after being thoroughly cleaned with water, and can see *no* imperfections in the lens, I would venture that there are no cracks. Any sort of flaw/crack/fracture would distort the light, and thus be visible.

[Beemer]

help me out

quote:
--------------------------------------------------------------------------------
Materials exposed to sunlight shall not undergo significant
loss of physical properties.
--------------------------------------------------------------------------------

Newsflash: UV exposure weakens most forms of plastic, significantly. Try taking some cheap plastic toy and leaving it in the backyard for a week or two. It will first fade away entirely, and then become extremely brittle. Realistically, though, you would have to be leaving your mask on a windowsill for it to have a noticeable effect...but when it did, you likely would not enjoy the results.

Well guess what that is a standard of ANSI. I will look again to make sure that wasnt in refference to the face mask, but they refer to the whole thing as an EPD, Eye Protection Device. Realisticly I wont drive around with mine on the dashboard eather. Call a goggle company and ask them how they test the lens what the material is and if it is affected significantly by UV. I suspect sustained exposer is a factor but I didnt see any mention of time.

quote:
--------------------------------------------------------------------------------
and if you get bunkered to just check the lenz? No there can be stress cracks that you Can Not see.
--------------------------------------------------------------------------------

If you put a mask on, after being thoroughly cleaned with water, and can see *no* imperfections in the lens, I would venture that there are no cracks. Any sort of flaw/crack/fracture would distort the light, and thus be visible.

What about stress effects you might not see?

[GT]

Re: help me out

Originally posted by Beemer

What about stress effects you might not see?

Might be alittle harder to detect via human eye. BTW my maks is from 99-00 so reguardless this thread has cuased me to purchase a new pair.

anyone ever use the raven photochromatic lenses before?