Now, for the part how it works, to spare you the googling, white it's technically logarithm equation, it's explained rather easily:
The number after "OD" is the amount of places you move the decimal point to the left.
Suppose your 1W 980nm laser. That's 1000mW.
OD3 goggles will reduce that by 3 decimal points, or 1.0 mW.
You will notice that is one-fifth of the limit for safe optical exposure for visible lasers. Invisible lasers have even higher threshold because they do not "flash blind" the optical nerves (primary concern with visible lasers, i.e. pilots and laser accidents), you have to get high enough in power to actually cause thermal and chemical damage.
You suggest OD8+.
Even IF you manage to find them without having to sell a kidney, you may notice that reducing 1000mW to 0.00001mW is totally an overkill.
I hope you can see the logic behind all this and when you do hand out safety advices to members (which is commendable!), I hope you do it accurately and professionally.
Judging by your nickname, you're well versed in computer hardware.
Your laser safety advice is equal to reccomending liquid nitrogen cooling for a 77W TDP processor.
Or in other terms, reccomending GFX Titan for GTA San Andreas.
You are not even aware you have a reduced awareness problem.
Contrary to what you may think, money doesn't grow on trees here.
$150 is far more than I'll ever be able to spend on laser goggles alone. I can build two lasers for that.
I will never be able to afford faster than 10 Mbits connection, fullHD monitor or Radeon 7970.
So why go for something like that, when something at 1/10th price will do EXACTLY the same thing?
Different thing when you're dealing with 100W bar assembly, because then the goggles won't cost more than the laser itself. If it does, you're overkilling it. And probably being a little bit paranoid, and *probably* have a bit of a superiority complex in the tone of "I can afford biggest and the best! You all need to buy it because I can."
50 Watt YAG
75 Watt YAG
100 Watt YAG
60 Watt CO2
150 Watt CO2
165 Watt CO2
180 Watt CO2
200 Watt CO2
600 Watt Fiber
1,000 Watt Fiber
2,600 Watt CO2
7,500 Watt CO2
These make any pointer or handheld look like insignificant irrelevancies ,that's just what I have to deal with every working day, I don't use OD8 goggles as there is no need. If there were I'd have the HSE inspector climbing up my rear end in a heartbeat.Having too high a rating will cause problems in itself, if you can't see your surroundings the laser becomes more dangerous not less.
If you value your eyesight, you wouldn't even consider a 100W diode stack for a _second_. Goggles or not, you don't mess with that stuff for a hobby, especially when you have no idea what you're doing with high powered lasers.
My reference to wearing a brick was a real life example, BTW. You won't see anything through OD8+ goggles, how do you expect to see which way you're even holding the laser?
Dan's spot on Gamer, diode stack power levels aren't fun, it's not about nice looking beams, it's not about popping balloons or having a giggle with your friends or nice hosts.
It's about light industrial potential at that sort of power, lasers like that don't forgive mistakes and they certainly don't tolerate fools.
In 11 years I've never seen anybody make two mistakes with industrial power lasers.
Hakzaw1 I agree. there is too much going on with the blue wavelengths. They kill retinas.
The cones in the retina can't reset when blue light is involved. It's like pulling the trigger on a gun, you are pulling the trigger like it's an automatic when it's a single shot. All you do is brake the trigger.