"Artemus" wrote in message
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"Existential Angst" wrote in message
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"mike" wrote in message
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I want to look at the eclipse this weekend.
Everybody says a #14 welding shade is good.
I don't have one.
So, how do the numbers stack up when you use 2?
I'm guessing it's not linear, so 7+7 doesn't = 14???
What's the math for stacking welding shades?
More than the dark factor, for eclipses, is the UV factor, and window
glass (and plastic) is fairly opaque to UV.
Beer's law would proly indicate that more lenses would be better for UV
than one dark lens, regardless of the net tinting.
http://en.wikipedia.org/wiki/Beer%E2%80%93Lambert_law After all the
bull****, Absorption is linear with thickness.... LOL
Of course, Snag's advice is always good.
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EA
Arc welding puts out lot's of UV. Why wouldn't a helmet already
have UV filters in it?
Even better for eclipses!
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EA
Art