A new building is going up near my workplace, and, naturally, welding has ensued. Being lawyerly types, those in charge have placed warning signs on the windows of my building to deter people from watching the admittedly fascinating light. Now, I don’t doubt that welding without a helmet could be bad for your eyes, but I’m skeptical about the risk in this case; we’re at least 100 yards away. Can such distant light from welding really damage one’s eyes? If so, by what mechanism?
The closer in you get to the site of the actual welding , the more damage you can cause to your retina’s. If your about a football field away ,then no , you should not suffer any adverse effects.
Should you start to see a starry pattern in your vision , followed by a throbbing headache , then you are too close, apply visine allergy drops and plan on half a day down time.
Declan
Arc welding generates copious amounts of UV. No, sneaking a peek here and there isn’t going to make you go blind instantly, but UV damage to the retina and the cornea is cumulative, to some degree. I think 100 yards is plenty far enough not to worry too much about it, as long as you’re not watching them weld 8 hours a day.
Oxy-acet and other gas welding proceses don’t pose a similar risk of UV damage. It’s just electric arc welding.
A welding arc is a very bright point source, and emits a lot of UV. I can personally attest that you can get a nasty “sunburn” from walking around a workshop all day where a lot of welding was going on. (TIG welding, and I was no closer than 2 yards.)
That said, at 100 yards I share your skepticism! Lawyers tend to push the safety boundaries beyond practicality or reason.
Just so you know, they like to call it GTAW now. And MIG is now called GMAW. I have no idea why the switch, they basically mean the same things, but I’ve noticed it over the last few years. Maybe welders think they sound cooler.
That is only on the welding certificates. 
My husband calls it TIG and MIG. Of course, he had an old school teacher who is about retirement age. (And his teacher got a nasty sunburn because the classmate who was to take a turn being my husband’s pipefitter was out for a day, so the teacher had to do it.) I wouldn’t use Visine in my eyes, just plain saline, and rest them. (As in, don’t read the computer moniter and don’t do other things that could add to the strain.) If you are seeing spots or having pain go to the doctor to get your eyes checked.
Hmm. Not to hijack (well, ok, maybe a little), if he knows anyone looking to unload something like a 100-amp stick welder, drop me an email. I’m on the lookout for a cheap used one–for as rarely as I’d need it, I’m not about to pay $200-$300.
I know, along with SMAW and SAW among other things! But TIG and MIG and stick trip off the tongue better, IMO.
I pretty much got the job that left me with weld-burn on the strength of the information here. Being able to translate oldweldspeak to newweldspeak impressed at interview, apparently.
Bolding mine.
Although I wasn’t welding at the time, the experience I had was virtually the same. It was about 8 years ago and I was still working as an electrician when I had the misfortune to be working on an extremely crowded switchboard on which I had to install a couple of circuit breakers. In the process of of pulling the wires (using insulated pliers) through the holes I drilled in the face of the switchboard, I managed to short out the tip of the pliers between two terminals on a circuit breaker, which along with making a huge bang, also created an explosion of intense white light of which I copped the full brunt. I was blind for a couple of minutes and a bit dazed, but otherwise I thought I was unharmed. That was until I tried sleeping that night with what felt like razorblades embedded into my eyeballs.
Although I’ve since recovered, it’s not an experience I’d wish on anyone else.
Once upon a time, when I spent a summer commercial fishing, I sat on the dock with a six pack and was fastinated watching the reflection of an arc welder in the water. Someone was welding on the rigging of a shrimpboat and I just could not take my eyes off of the perfect reflection of the arc in the river. That night I felt like I had acid thrown in my eyes because the burning sensation was so intense.
My welding instructor said that back when he was welding full time he’d give himself a welding flash every now and again. He had his routine all worked out. He knew how his eyes were going to feel in a couple of hours. He also knew that in about 12 hours he’d be fine. So he’d call his wife, get her to pick him up and take him to the hospital where they knew him and knew the SOP (he was working in an outback mining town).
They’d douse his eyes in local anasthetic, put patches over them, his wife’d drive him home, he’d take an appropriate number of sleeping pills, and he’d wake up the next day and be fine.
He said suffering from welding flash was the worst most painful thing he’d ever experienced and, as he put it, “he knew what his eyes were going to go through, and just didn’t want to be there with them for the experience” 
Um, yeah… Sorry, wrong forum. :o
Or welding engineers.
Arc welding - utilizing an electrical arc, for example those below, plus other types such as drawn arc.
MIG - metal inert gas
TIG - tungsten inert gas
GMAW - gas metal arc welding
GTAW - gas tungsten (which is a metal) arc welding
There’s spray welding, which is an arc-fusion type of weld, and it’s also called a MIG process, so I suppose therein could be the reason for the differentiation. But this doesn’t apply to TIG, so I wouldn’t see a reason other than consistency in naming.
I think the American Welding Society calls them GMAW and GTAW officially.
If you look closely you will notice that besides the mask arc welders keep their sleeves rolled down and their shirt collars buttoned up. I once had a project that involved considerable welding. At the start I wanted to see how the pieces would actually go together so I watched the welding for a couple of hours and I had the collar of my shirt unbuttoned and no gloves. I wound up with a pretty good “sunburn” in both places.
Might be some trademarks at play here. Old-timers may refer to TIG as Heliarc, which was a brand name of Linde (now Praxair), a prime supplier of helium and other welding gases.
Otherwise it does seem strange that they’d go from Tungsten Inert Gas to Gas-shielded Tungsten Arc Welding. It certainly bucks the TLA trend. (Three-Letter Acronyms)
I too have learned the hard way about UV burns from electrical welding, in particular the time some goggles with factor-11 glass protected my eyes wonderfully, but left the rest of my face to burn. The light spectrum in electrical welding arcs contains a lot of nasty UV-B and even nastier UV-C, and doesn’t even give a good suntan, just radiation burns. Here’s all the UV occupational safety data you could ever need, with handily defined exposure levels relative to wavelength. I leave no bit of flesh exposed now when MIG welding, and all I need to do now is fettle some breathing apparatus so the fumes don’t corrode my lungs. It’s one of the reasons why welders usually didn’t live to a ripe old age in the days before health and safety, proper masks and ventilators.
It’s not just UV light that can be damaging; any sufficiently intense light will burn, it’s just the body is more sensitive to shorter wavelengths. A focused beam from a CD (infra red) or DVD (red) or Blu-Ray (violet) burner laser is enough to permanently blat out a few retinal cells forever. The effect is cumulative, and usually goes unnoticed in the early stages. Laser pointers aren’t really safe for eyes either.
As for the optical power levels versus distance from light source - it’s an inverse square law, like all radiation, so for example, standing 3 metres from a light source will expose you to 1/9th of the optical power than if you stood 1 metre away; stand 4 metres away and it’s 1/16th etc. (This is for an unfocused light source like a very hot glowing thing, not a laser beam or spotlight).
(nitpick)Most spotlights also diverge within the beam according to the inverse square law. It’s just that most of the light is contained within the beam so they start off brighter. If the source is a point source at the focal point and the reflector is a parabola the beam will come out as parallel rays and will not diverge. This works well for the large 4 or 5 ft. diameter searchlights with a carbon arc as the source because that is close to a point source. For most spotlights, though, the reflector or lens is small and the source isn’t a point so most of it isn’t at the focal point.[/nitpick]
It is true of lasers which do emit a beam of parallel rays. The only thing that dims them with distance is scattering.
The reason Tungsten (which is a metal) is differentiated from typical GMAW is that in Metal arc welding, the fill metal is in the form of an electrode which melts and becomes part of the weld. With GTAW the tungsten (which is metal) is an electrode which does not melt, it just carries the arc and the fill metal is fed separately.
Of couse, anyone who followed the earlier excellent link already knows that. Man, that James Blunt is one heck of a source of welding knowledge!
There is spray arc and short-circuit arc MIG.
You can watch SAW (Submerged Arc Welding), an electric arc welding process, without eye protection since the arc is generated under a mound of flux that looks like dirt.
I have to generate all these welding procedures for the various processes/materials. We mainly use GMAW, SMAW, FCAW (Flux Cored Arc Welding), SAW, and GTAW.
The OP has been answered, but in practice SMAW is IMHO the worst as far as getting flash burns from casual contact. The others all have a gun close to the arc that can block the arc from some directions, but the arc on a welding rod is a ways from the electrode holder, so the arc is visible from more angles. At 100 yards, I wouldn’t sweat it.