Hope this is an appropriate question.
I want to set up a 12 x 12 shield to protect my eyes from the laser.
It is a blue diode 30W laser in the range of 450nm wavelength.
The safety glasses that came with it were a dark green.
Will a sheet of 1/8" dark green acrylic (plexiglass) provide proper protection?
If not what color os acrylic should I use?
It is strange there are no videos on you tube about this.
Is there a chart or reference somewhere on the internet.
I have a bad habit of wanting to watch the laser in action.
Why would the manufacture include dark green glasses with the laser if they are not effective?
I see the light shield on some other blue diode laser modules are red ā¦ are they ineffective also?
I have ordered a sheet of orange acrylic from ebay and will follow the suggestions given here.
Thank for your replys and help.
and I thought I was a safety nerdā¦
You called itā¦ 
Money. There is no regulation by our government. They put in honeycomb bedsā¦
There are a number of videos around on laser safety.
Some people are driven by fright, not logic or reason. Like much of our legislation. Some of these people are so scared of their machines, I wonder why they own them.
The first thing I did was disable the door since my heads in it most of the time.
You want to stay safe with anything, understand how it works. The only time I lower the top is when the ventilation needs a helping hand and then itās open about an inch.
Oz edit - The advice that follows is ONLY relevant for CO2 lasers, not diode lasers: I wear glasses, they are polycarbonate and can be cut with the laser, and are therefore safe to block ir emissions of a co2 machine.
If you are purchasing this from a manufacturer, they can tell you what light it will transmit. Pretty much if you can see the actual beam, that material wonāt help you much. With ir itās a little more difficult but any polycarbonate or acrylic will make good eye protection.
If this stuff wasnāt operational without all the safety equipment, you couldnāt fix it or work on it. The safety stuff is generally there for the operator. Anything that moves like a cnc is potentially dangerous.
Pretty much like āDonāt look into the laser beam with remaining eye.ā
Whom do you know thatās actually had damage from a laser?
About 10% of the people I know have a laser. More of them have been hurt working around the home or in a car than the injuries from lasers. Some have even put their eye out and lost fingers with power equipment, all much more serious than any of the laser owners injuries.
Some of the K40 people have put their finger in the beam path before the lens. Claimed it was like a cigarette burn. I think thatās being an idiot.
I donāt like to feel pain, so I keep my fingers out of the machine when itās running.
In the end, itās all relative.
I know how they work and donāt fear them, just use common sense when I work around them.
And while weāre at it, a little PSA:
If you blue laser came with those green glasses, throw them out and get at least the red ones if you donāt want to spend the money on proper safety goggles.
I can still see blue LEDs as being blue with the green glasses, I would not want to be in the same room as my lasers with them.
(BTW, I still keep the red glasses around for emergencies, but I got a couple of $9.99 webcams and pause the lasers when I need to get into the room. I trust my walls to block laser light much more than any glassesā¦)
I have a flash curtain over my window in the workshop as I tend to do quite long burns, say up to 100 4 inch circles at a time with cutouts so 30 to 45 minutes running time with setup, I also have lights on the door which are lit up when I go in, they are not connected to the laser, having them on all the times helps with no one coming in to room. I also have some labels on the door about wearing the goggles hanging on the door if you want to come in, but knock first. so far the kids have kept have obeyed the rules and my wife doesnt come in anyway as its not neat enough for her minimalistic way of life. My shop My rulesā¦
No kids, a dog, she lays on the driveway most of the time, cats are inside, so they arenāt an issue.
I have no problem with people taking precautions they feel comfortable with. I have run a few jobs, like a 12"x12" mirror that most of the coating had to come off, so it ran about 1hour and 20. In the garage with it, but got board pretty quick watching it and did other things, in the garage.
I seem to enjoy watching a vector cut, but scanning is pretty boring.
Since the OP asked about appropriate 12" x 12" laser shieldingā¦ Iāve purchased a couple of panels from these folks. They have sizes up to 24" x 24"ā¦
The dark green glasses work, but arenāt quite as effective as the wavelength-tuned orange acrylic that is sold specifically to block the 405 - 450 nm wavelength from diode lasers. The dark green is basically āsunglassesā, which helps quite a bit. Even the orange acrylic could be better - it lets through a lot of the āflareā that happens from burning, and staring at that for too long is similar to staring at a welder.
" This is the BEST you will find for the price!"
I bought a number of things with this same endorsementā¦ 
Retrosmith ā¦ I bought a sheet of what you recommended and it works great.
Use it for a moveable shield so I can watch my 30W diode laser do its thing.
You can tell right away it is working as you can barely see the blue alignment beam to focus.
Thanks for the link.
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