On Thursday, May 17, 2012 at 12:53:14 PM UTC-5, mike wrote:
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?

Thanks, mike

I'm not sure of the shade # but once before during a partial eclipse my brother doubled two shade glasses in a welding helmet and it was perfect. My dad is dead now or I'd ask what his power was in the helmet. He did it for a living so it probably was two #11's.