[taiwanluthiers]

I don't know if this is normal, but I've been having trouble with auto darkening lens that fits in a standard 2 x 4 inch visor that would lose sensitivity over time. At first it would work with TIG welding, but then it would require increasingly high current for it to trigger, and one of them won't even trigger at all doing 100 amps stick welding. What's causing this to happen? I tried leaving it in the sun and it doesn't fix anything. Only remedy is get another lens and hope it doesn't too lose sensitivity.

[tweake]

what brand/model?
can you post pics of it?

[taiwanluthiers]

I have no idea, if I told you the brand you wouldn't recognize it, but it's Chinese made.

They will work when looking at a bright light, but not welding light or sunlight when they do break.

[tweake]

if its the cheap non-adjustable ones then throw it in the bin. you can't fix them, they are disposable. those size lens are made to fit in the old style cheap fixed lens helmets.
you need the fully adjustable ones. adjustable shade, adjustable sensitivity and adjustable delay. even the cheap ones here have all that (and yes i have one as a spare). get a decent helmet with a decent size lens.
you can waste a lot of money buying cheap crap. stick to good reputable brands.
you can't weld what you can't see.

[taiwanluthiers]

I used to have one that lasted quite some time, didn't go flashing or anything. I mean I'm just using them because they are a standard size that fits standard helmets. I could buy dedicated helmets but then finding replacement lenses will be harder.

What is causing them to fail? The lenses are really cheap, they're literally a buck each when I buy them from Taobao, so changing them out isn't really financially draining. But it's telling that light activates them, but not sunlight or welding light, which presumably it's because of the UV. I am using the filter in front of it so it's presumably blocking all the UV lights, but how can I block out all the UV lights from hitting the sensor? Perhaps the UV light is damaging the light sensitive transistor that triggers it?

[tweake]

I mean I'm just using them because they are a standard size that fits standard helmets. I could buy dedicated helmets but then finding replacement lenses will be harder.

you normally don't replace them because they rarely fail. mine are 6-7 years old now. tho i can still get replacement parts if i needed to. good brands are well supported.

What is causing them to fail? The lenses are really cheap, they're literally a buck each when I buy them from Taobao,

yeah thats why. cheap copies.

[taiwanluthiers]

Then what quality 2 x 4 lenses you recommend? I'm thinking it's the uv keeping them from triggering, which is why they have a shield on it. Explains why light triggers it but not the sun.

[tweake]

Then what quality 2 x 4 lenses you recommend? I'm thinking it's the uv keeping them from triggering, which is why they have a shield on it. Explains why light triggers it but not the sun.

i recommend none. no one that i can see even sells them here. buy a decent helmet.

the shield is to keep weld splatter off it. the uv is filtered out by the unit itself.
its the brightness of the arc that triggers it as thats way brighter than the sunlight is in your room.

[tweake]

i had a look at some other brands of auto darning lens. Lincoln make one at around $200us. a company i know of sell another brand but thats still more than what you can buy a whole complete helmet for.
i have heard of ones being made for pipeliner setups but $$$$.

i found a local non-welding shop that sells a none adjustable electronic one very cheaply. no brand so i'll bet that its a copy that last 5 minutes.

just buy a decent helmet.