Originally Posted by 66GMC
. Guys that used both a "cheap" helmet and a "quality" one will tell you about "welding flash" ... and having "itchy / scratchy" eyes when they use one with a low response time.
I have been told that the best test of response is to "flick your bic" cigarette lighter in front of it. If the shade doesn't react to that, you'll be exposing your retinas to all of that UV radiation for nanoseconds everytime you strike an arc.
These things have been around for over twenty years now and this old myth is still around and as popular as ever. The response time has exactly zero effect on UV and IR exposure and a delayed response WILL NOT BURN YOUR EYES! The time it take for these things to go dark, or even if they fail to go dark, will not expose the user to any more UV and IR than a fast response time because the protection is a fixed function and DOES NOT have to rely on the lens going dark. The darkening effect of the lens filters the visible light spectrum and the IR and UV rays are blocked by the lens material which functions exactly the same whether or not the lens goes dark, from a safety standpoint it does not matter if the lens goes dark or not because the protection from the harmful rays will be the same dark or not! Accidentally blocking a sensor and having the lens fail to go dark (hey this happens all the time!) will not expose the user to any more harmful rays than if the lens had of gone dark at the proper time, although it may be uncomfortable it will not burn your eyes even if it happens repeatably.
There are a bunch of "urban legends" around about some poor worker who was blinded by these helmets but they are nothing more than BS. It usually goes that a welder was issued one of these helmets by his employer (usually at one of the auto plants) and he complained to his supervisor that it was not going dark fast enough but of course he was told to "use it and quit complaining or go home". Well this poor guy obediently goes back to work but his eyes were hurting so bad when he got home that he went to the ER where he was told that it was too late and that his eyes were burned so badly that he was going blind from excess exposure!
There are several variations of that story and one has it that the helmet was working properly but the guy had a job doing tack welds or some such that required striking the arc a large number of times per shift. These stories are common along with the "scratchy eyes" one but they simply are not true and as one of the reps from Jackson once said "If that was possible the workers comp and product liability lawyers would ruin us overnight"! I suppose it might be possible to hurt your eyes from continuing to use one of these things if the lens would not go dark for some reason but this would come from staring too long at the bright light and would be no different than staring at a light bulb, possible I guess but who in their right mind would do such a thing?