Too bad I didn't read all these safety tips before shooting pictures of welding, and relative close ups, and longish exposures including the welding arc.
shot both stick and TIG welding being done this way.
I think I remembered to use a a filter once, after I realized my favorite shot of a welder came out from it.
I use a polarizing filter most of the time, I find it really helps with the sky, unfortunately I have just learned I was doing it wrong the whole time(Linear filter I assume because it changes the level of darkness in the sky when I rotate it)
For welding, it seems to work fantastically, giving much better definition.
If using lightroom, I like to bump the clarity up, I find most welding arc shots will take on a bit of a star effect if you do that, and use recovery/fill light to balance some of the difference out.
The bit about spatter etching lenses is very true, I've etched the sapphire crystal of my watch with spatter unfortunately.
I don't know about the whole safety glasses requirement, I shot looking right through my viewfinder, with so many layers of glass, I'm not worried about getting flashed, but I do make sure not to look up.
I've definitely seen the arc with my eye naked a few times in my life, not the best thing to do, but if you're quick it won't hurt physically anyways, it's not that potent. The potential damage from it is certainly dramatically lower than that of a laser, I have had my sensor exposed for up to 1/15th with no filter(other than the lens, which filters UV anyways to a large extent I believe) and no damage yet. I wouldn't try that with a laser, which is visible light spectrum, and much less diffused.
Those lasers are much, much more potent, and focused in a smaller area too.