Quote:
Originally Posted by mepstein
I don’t know much about the helmets but I thought the darkening was to let you see but it’s the lens that actually protects your eyes whether or not it darkens. Similar to how a regular clear pane of glass will block out a lot of the sun’s radiation.
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The default shade of the lens, shade no. 5, will protect the eyes against an accidental arc flash. Not intended to protect during any significant length of exposure. Lowest recommended shade is 9 with 10 being more common and up to 12 for TIG welding.
The speed of the lens is very important. I wore an HF helmet in welding school and I had floaters in my eyes as a result. I stepped up to a much faster (and more expensive) helmet and have had little problems since.
Regarding your comment about clear glass blocking radiation, it doesn't do much. Only if the glass gets hot can you assume some IR radiation is getting trapped. You wouldn't know about UV. (I think elsewhere I mentioned IR when I meant UV.)
I also have the static lens I mentioned which has more than a shade of 10, it has a mirrored coating a lot like an astronaut's outside helmet. That's as good as you're gonna get.