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FrozenGate by Avery

O-like has a 3.2W IR for sale on ebay !






@potaorage & jeffd...

When Laser safety is concerned... I'd rather Overreact than Underreact...
and be wrong...

IMO anyone using "High powered Lasers" without some sort of eye protection
is just plain irresponsible..

If they think that they themselves do not require Laser Safely goggles when
operating "High power Lasers"...
then they must surely think that any bystanders don't need them either...
Like I said............ it's irresponsible...

But then again... if it's just yourself... I don't really care if YOU want to risk your eyes.

BTW... Elektrofreak is right on the money.....


Jerry
 
Ok I'm sorry that I made some *irresponsible* comments-- You can feel free to ignore them
 
sbdwag said:
Im not sure if the word fun would be appropriate. Perhaps responsible, safe, enlightening, forwarned, experimental, dangerous, playing with fire, all seem to enter my psych more than fun.

It bugs me that a reflection that I cannot see might partially blind me. That is what scares me about this unit. But I bet the sucker would burn wood at thirty feet.

If I owned one of these I would mount a red sight laser on it just for safety

regards
sbdwag
Click to expand...

No i meant fun..
 
ElektroFreak said:
So let's be clear: it's 3.2 WATTS. Not uW, not mW. WATTS [...] at these powers it only takes about a millionth of a second for a serious burn to happen.
Click to expand...
Well, 3.2W is far less than the amount of sunlight you get on your palm if you hold it out into the sunlight. It's not a great amount.

Laser pointers of a few dozen mW are dangerous ONLY because the eye focuses the energy onto a spot on the sensitive retina with a diameter on the order of a dozen micrometers, resulting in very large energy densities (amplification factor 10^5).

Most people know that BR dots look odd, because the eye can't properly focus that wavelength: you're shortsighted in near-UV. Similarly, for IR, you'll be farsighted, and that light won't be focused well either. Then, red and IR wavelengths aren't very well absorbed by tissues, so little localized heat will be generated.

Here is a document about maximum permissible exposures (MPEs), from a reputable source. For example, for 633nm and 0.25s exposure, it's 2.5mW/cm2. For 840nm, it's 1.9mW/cm2 - but for a 10 second exposure. For 10.6um (CO2) and 10 seconds, it's 100mW/cm2. So you can see that the danger level decreases quite rapidly with wavelength. These MPEs are for work safety, so there'll be a considerable safety margin in there as well.

For diffuse reflections, the table on page 3 shows that even lasers with hundreds of watts in IR are harmless a meter away.

I'm not saying that you should be careless with a 3.2W diode - but it's not a death ray, and hysteria is not the answer.
 
So what about say a specular reflection off of a metallic, shiny or glass material of a focused beam. Even at 10 percent reflection your talking 320mw that you cannot see.

How dangerous is that?

regards
sbdwag
 
dr-ebert said:
Well, 3.2W is far less than the amount of sunlight you get on your palm if you hold it out into the sunlight. It's not a great amount.

Laser pointers of a few dozen mW are dangerous ONLY because the eye focuses the energy onto a spot on the sensitive retina with a diameter on the order of a dozen micrometers, resulting in very large energy densities (amplification factor 10^5).

Most people know that BR dots look odd, because the eye can't properly focus that wavelength: you're shortsighted in near-UV. Similarly, for IR, you'll be farsighted, and that light won't be focused well either. Then, red and IR wavelengths aren't very well absorbed by tissues, so little localized heat will be generated.

Here is a document about maximum permissible exposures (MPEs), from a reputable source. For example, for 633nm and 0.25s exposure, it's 2.5mW/cm2. For 840nm, it's 1.9mW/cm2 - but for a 10 second exposure. For 10.6um (CO2) and 10 seconds, it's 100mW/cm2. So you can see that the danger level decreases quite rapidly with wavelength. These MPEs are for work safety, so there'll be a considerable safety margin in there as well.

For diffuse reflections, the table on page 3 shows that even lasers with hundreds of watts in IR are harmless a meter away.

I'm not saying that you should be careless with a 3.2W diode - but it's not a death ray, and hysteria is not the answer.
Click to expand...

Was somebody being hysterical?? Once again, I'll just forward you to Sam's Laser FAQ.. read the entire safety section. I'm sure that you are very much more knowledgeable than the folks who wrote that.

You may be right about 808nm light. You can quibble about power levels vs. wavelength and throw out some math, but that doesn't mean that I'm going to go onto a forum with a lot of members who's only knowledge of lasers is that their greenie won't burn stuff and tell them it's safe to play around with a 3.2W IR laser with no goggles. A lot more people read these posts than just the OP. If you want to, by all means be my guest. I know, I know: Because I promote laser safety, I'm hysterical.

Let me offer a wiser position that has been my only point all along: Just be careful, since you only get two eyes. Why risk damaging them at all? A set of goggles will set you back what? like $40. That must be hysterical, me suggesting safety. (I apologize to everyone for my uncontrollable hysterical outbursts.)
 
ionlaser555 said:
Hi



What wavelength do things like wood and plastic start to become opaque i guess co2 laser is absorbed very well by most things ?
Click to expand...

I believe that once you go below about 3000nm, visibly transparent substances like clear glass and plastic begin to be opaque and will burn or melt. Very few lasers operate in this region, and generally those that do are exotics that few people are familiar with. The chemical oxygen iodine (COIL) laser that is being developed as a laser weapon by the military is somewhere just below 3000nm, and the carbon monoxide laser is around 5,500nm. There are also other types of laser that have non-dominant lines in these mid-IR ranges, like the HeNe at 3,391nm. Lasers of wavelengths that cannot penetrate substances that can transmit visible light are often considered to be "eye safe", but don't let that fool you.

You surely wouldn't want to get hit in the eye with a 20 watt CO2 laser! While the beam cannot pass thru your cornea and hit your retina (as can 808nm) it can certainly ruin the surface of the eye. But the reason such lasers are termed eye safe is because specular reflections are a lot less likely as most substances, including metals, absorb rather than reflect the beam.

Just remember that anything with a wavelength above 3000nm (and below UV, I'm not sure where the cutoff point is there where transparent substances become opaque, but it's probably above 300nm) behaves just like visible light, even though you may not be able to see the beam. It can reflect off shiny surfaces and pass thru (and partially reflect) clear glass, plastic, your cornea, etc.

IMO if I was working with 3 watts of IR, especially to burn things, I'd wear goggles for sure.
 
Thanks for the info

Basically specular reflections even though they are not visible can still be very dangerous at 808nm because some of the ER is still being reflected and not absorbed and you need to go much lower near 3000nm before shiny surfaces are absorbed more completely.

Is that correct. My logic is I know how dangerous specular reflections are on a 405nm laser and how bad they are on a 650nm laser. It stands to reason that a 808nm even though you cannot see them specular reflections are still present and can do you much harm.

thanks


regards
sbdwag
 
It is a definite possibility, but the severity of this threat depends entirely on the type of surface the specular reflections are coming from. A flat painted wall will not produce harmful specular reflections from just about any hobbyist laser, even several watts. A 40W 532nm Laserscope, for example, WILL produce harmful specular reflections from a flat painted surface, in part due to the wavelength and in part due to the sheer power.

Basically when it comes to specular reflections, common sense pertaining to the surfaces you allow the laser to reflect from will go a long way toward safety, but the threat of an accidental non-diffuse reflection still remains and is cause enough to wear eye protection whenever you are in the same room as the laser. Wristwatches and other jewelry, polished metal (door hinges, plumbing fixtures, lighting fixtures) glass vases, window panes, etc. etc. and many plastic surfaces can cause non-diffuse reflections that can be extremely dangerous. Unless you are operating the system in a room that is 100% free of the possibility of any of these threats, then goggles are a must.
 
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Its not really that much of a concern to me. When there is power to the unit I will have googles on. But there might be a few times when I would like to not have them on. such as focusing.

I wonder what kind of background material I could use that would absorb ER but not burn. Im looking to build a ER trap. You can buy them but they are $165.

Heres a link to it
Laser Beam Trap


regards
sbdwag
 
Sheet metal painted flat black would work. It's the shape of the beam stop that makes it work. It has a cone in the middle of the cylinder, and you center the beam on the tip of the cone and it diffuses the light evenly around the inner surfaces of the surrouding walls, You could get away with making a small box covered on all sides except for a slot. Paint the inside and outside flat black before building and shine the laser beam into it at such an angle so as to not allow any light back out except a little in whatever direction you deem safe, and you could easily machine the real thing if you have the right tools or know somebody.
 
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i lose a part of my eye sensibility when i was doing experiment with my 1W pump diode at 808nm. Now i know that even unfocalized beam are dangerous; owning a IR burner just for fun is too dangerous coz this beam is partially focalized; plus it's not very fun because the beam is almost invisible. The only use of this unit would be pumping some crystal
I dont trust 808 nm, a mistake can be done very fast, and you would regret it. just my opinion
 
dr-ebert said:
Well, 3.2W is far less than the amount of sunlight you get on your palm if you hold it out into the sunlight. It's not a great amount.
Click to expand...

"Sigh...." My palm measures aprox. 10cm X 14cm = 140 sqare cm.
With the sun's power at 1366watts/meter that would be aprox 19 watts
on an area of 140cm.

I'd like you to take a 13.4cm diameter magnifying glass (aprox area 141sq.cm)
and focus that weak sun's beam onto your palm and let us know if it
causes any damage to your skin... let alone your eyes...:eek:

Please wear good sunglasses when you do this experiment...


Jerry
 
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