Forgive me if this is a well hashed topic - I'm really just looking for more opinions from people in the trenches. (And I only drop into RCM about once a year it seems...)
It seemed to me that since there is a finite amount of time that an auto-darkening helmet takes to respond, that cumulatively this epxosure could in fact be harmful (0.001 second times 2000 arc strikes in a work day, or whatever....)
This guy, who should know a whole lot more about it than a novice amatuer welder like myself would, thinks otherwise:
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Anyone care to give me their 2 cents before I run out and buy one of these things? And if they are really comparable to sliced bread, is there a favorite model?
All of the auto-dark welding helmets provide UV and IR filtering at all times so there is no risk of eye damage even on the occasions that you block the sensor and they don't darken. You'll be blinking for a few minutes, but no UV or IR gets through.
"Mickey Feldman" And if they are really comparable to sliced bread, is there a favorite model? ^^^^^^^^^^^^^^ There have been two schools of thought on this:
1.) If you value your eyes, you will not buy a cheap helmet.
2.) The cheap helmets do the job, and they're a better bargain than the costly ones.
I use a helmet from Harbor Freight that goes on sale frequently to $49.95. There has been a shift among those posting here, and in sci.engr.joining.welding. The acceptance of these cheap helmets seems to be growing.
I have found one situation where a better auto-dark is superior--very low-amperage TIG (for thin material). I found that cheaper helmets would not respond reliably to the arc, and better ones do.
Except for that, the cheapies work fine in my experience.
I suspect the effect of 2000 arc strikes limited to .001 sec or less, is equivalent to being outside in the sunshine for fifteen minutes without glasses or sunglasses. ( regular glasses block most UV ).
I'm glad to hear that even the inexpensive models do the job they're intended to do.
Although having been blessed with excellent eysight for most of my life, I've now passed that stage where I have to hold the book further and further from my eyes to achieve focus, found that my arms simply aren't long enough no matter how far I stretch, and that I need reading glasses. So at the very least I think I'll get a helmet that allows the use of a magnifying lens. Variable shade control sounds awful useful too, for related reasons. This may rule out the bargain models, but I can live with that. I'd rather spring for high quality in the beginning and not kick myself later for false economies.
"Mickey Feldman" wrote: (clip)I've now passed that stage where I have to hold the book further and further from my eyes to achieve focus, found that my arms simply aren't long enough no matter how far I stretch, and that I need reading glasses. So at the very least I think I'll get a helmet that allows the use of a magnifying lens. ^^^^^^^^^^^^^^ I wear trifocals, but when I use the helmet, I switch to a pair of reading glasses. I prefer them to the diopter corrections that fit the helmet, because:
The helmet already has a protective front shield, a variable filter, and a protective rear shield. If you add the diopter correction, that will be a total of 8 surfaces that can collect dust. You can gradually accumulate dust and scratches on all those surfaces without realizing how bad it is getting. If you wear the correction on your face, at least that is one pair of surfaces that you will keep clean.
When you get to the point that you need bifocals, or tri- like me, you will find that getting a line of sight through the glasses and the helmet gets more difficult. ^^^^^^^^^^^^^^^^ Variable shade control sounds awful useful too, for related reasons. This may rule out the bargain
^^^^^^^^^^^^^^^^^ My cheap HF helmet has adjustable shade control. The place it could fall short (according to one poster) is in sensitivity to low current welding light. I haven't had that problem, but that may be because of the limited kinds of welding I do.
My near vision needs more correction than the diopter lens allow, at least the ones normally found on the shelf. Instead of my bifocals, I wear single focal length side shield safety glasses. I had my optometrist set the focal length at 18", which is about right for me. One strange thing I found out here is that plastic is better than glass for hot work. The tiny hot bits of metal instantly adhere to the glass, but not plastic.
Note that there are at least three kinds of plastic used for eyeglass lenses, plus two more used only for magnifiers.
CR-39. This is the granddaddy. It is harder than epoxy, insoluble in all common solvents, and doesn't melt. This would stand up to hot metal droplets the best.
Polycarbonate. Very tough, but soft and vulnerable to most solvents, and melts easily.
High-Index. I don't know the chemical composition, but seems to be soft and vulnerable, like polycarbonate.
Polystyrene. Used for magnifiers, not eyeglasses. Very soft and vulnerable, and melts very easily.
Acrylic. I'm not sure what material this is in magnifiers made of "acrylic", but it seems to resemble polystyrene.
I just noticed that Lee Valley/Veritas has a series of self-adhering
+diopter lenses that can be put on glasses, face shields, etc. They appear to be a similar material to the fresnel lenses that adhere to your rear window (no adhesive required). I thought of getting a pair for the times when I have to work on circuitry over my head (well, some circuitry is always over my head), and the bifocals are on the bottom - big help.
In Lowes the other day, I noticed an autodarkening helmet for $100 (normal price). I opened the box, and other than some different stickers the Lowes helmet was identical to the $50 helment at HF.
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