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Artemus[_4_] Artemus[_4_] is offline
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Default How do welding shade numbers add up? Eclipse viewing.


"Existential Angst" wrote in message
...
"mike" wrote in message ...
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.
--
EA


Arc welding puts out lot's of UV. Why wouldn't a helmet already
have UV filters in it?
Art