Brick beamstop effectiveness?

[Rifter]

I have seen posted that a brick painted matte black can be used as a beamstop, my question is for how much power? Could you look at the dot on said brick from a 500mw laser? 1w? 2w?

 

[bdgreenb]

its not just painted matte black, most people use special spray on solution that is specially made for rough thermal conditions, IIRC its the same coating as on the thermal heatsinks for LPMs

 

[Pi R Squared]

I have seen posted that a brick painted matte black can be used as a beamstop, my question is for how much power? Could you look at the dot on said brick from a 500mw laser? 1w? 2w?

The purpose of using a brick as a beam stop is just to have something to point a powerful laser at without burning something or leaving scorch marks on your wall by accident, something I have done a few times. It doesn't necessarily have to be black, it will still stop any laser you will have. To answer your question about looking at the dot, it depends on distance and power density but generally speaking you shouldn't look at the dot up too close.

Alan

 

[Techrat]

This thread is just too close to a topic I am very interested in not to chime in. I would like to get some opinions on looking at the "dot", with googles/glasses on, from a 1.5-2W 445nm reflected off of a matte surface, say wood or dark plastic for example, at about 3 feet.

The glasses I have are Eagle Pair® 190-540nm & 800-2000nm Laser Safety Goggles which appear to be pretty well regarded here.

I am sure that extended viewing would not be advisable but how about long enough to focus the beam accurately?

My application is using the laser in engraving and I find that, goggles on, I sometimes find my eye drawn to the dot. I am considering building a non translucent enclosure just to force the issue but if the occasional viewing, goggles on, of the dot is pretty harmless, I won't go to the trouble.

Thanks for any feedback.

 

[Pi R Squared]

This thread is just too close to a topic I am very interested in not to chime in. I would like to get some opinions on looking at the "dot", with googles/glasses on, from a 1.5-2W 445nm reflected off of a matte surface, say wood or dark plastic for example, at about 3 feet.

The glasses I have are Eagle Pair® 190-540nm & 800-2000nm Laser Safety Goggles which appear to be pretty well regarded here.

I am sure that extended viewing would not be advisable but how about long enough to focus the beam accurately?

My application is using the laser in engraving and I find that, goggles on, I sometimes find my eye drawn to the dot. I am considering building a non translucent enclosure just to force the issue but if the occasional viewing, goggles on, of the dot is pretty harmless, I won't go to the trouble.

Thanks for any feedback.

Viewing the dot from a laser of that power up close should be completely safe with those glasses. If you want to be extra safe you could buy slightly better glasses such as these http://www.aixiz.com/store/product_info.php/cPath/50/products_id/202 and of course there are others to choose from but in my opinion it would be an unnecessary expense.

Alan

 

[Rifter]

You see im confused as to exactly what is safe and what is not. Ive seen so many different things posted, some people say don't view dot of 50mw + power laser inside house on any surface. Others say up to 500mw on diffuse reflection surface is ok to view just not specular reflection.

And the wiki for laser safety agrees with this listed under the class IIIB section:

"A Class 3B laser is hazardous if the eye is exposed directly, but diffuse reflections such as those from paper or other matte surfaces are not harmful."

Since a class IIIB laser is anything under 500mw that means it would be ok to shine say a 200-300mw laser at a matte white wall(diffuse Surface) and view the beam/dot correct?

I've also googled most university laser safety guides and they agree with the wiki that class IIIB on diffuse surface is usually safe to view.

This is why im confused so much conflicting info.

 

[deltawars]

You can look at a laser beam of any wattage just fine, unless your in a super dusty environment, I would say a rule of thumb if your eyes strain or hurt then don't look.
You should not look at a laser dot above 5mw, if you do you can get eye damage and very likely permanent eye damage.

If you use a laser above 5mw always ware laser goggles inside small areas, and when shining the laser dot in close proximity.

If you are outside only use laser goggles if you shine the laser in close proximity, but if you are shining the laser at the moon or far away, as long as the dot is far away you don't need laser goggles.

I have looked at a 120mw red laser dot a few meters away and i could feel my eyes hurting, if your eyes hurt or stain then the laser is to powerful to look at, but remember when your eyes are hurting you are damaging them.

 

[ChaosLord]

You see im confused as to exactly what is safe and what is not. Ive seen so many different things posted, some people say don't view dot of 50mw + power laser inside house on any surface. Others say up to 500mw on diffuse reflection surface is ok to view just not specular reflection.

And the wiki for laser safety agrees with this listed under the class IIIB section:

"A Class 3B laser is hazardous if the eye is exposed directly, but diffuse reflections such as those from paper or other matte surfaces are not harmful."

Since a class IIIB laser is anything under 500mw that means it would be ok to shine say a 200-300mw laser at a matte white wall(diffuse Surface) and view the beam/dot correct?

I've also googled most university laser safety guides and they agree with the wiki that class IIIB on diffuse surface is usually safe to view.

This is why im confused so much conflicting info.

The confusion comes from differing opinions combined with liability. It's easier to just say don't do it.

To me, it's one of those things you will get with enough experience. It doesn't hurt to start out learning to be cautious.

The fact that different sufaces and wavelengths can have different effects also play into this. Although with visible beam and black surface there is a pretty uniform absorption.

Example: no one can say all black sufaces are safe for dot viewing. If someone saw that, then focused a 1W+ 445nm laser on, say, a black piece of plastic, that could be very dangerous. If the plastic started to melt, it could become much more reflective causing enough of the beam to reflect to injure your eye.

I don't know why anyone would want to look at the dot without glasses up close. The actual dot (or line) can't actually be seen, and it is usually uncomfortable.

 

[Rifter]

The confusion comes from differing opinions combined with liability. It's easier to just say don't do it.

To me, it's one of those things you will get with enough experience. It doesn't hurt to start out learning to be cautious.

The fact that different sufaces and wavelengths can have different effects also play into this. Although with visible beam and black surface there is a pretty uniform absorption.

Example: no one can say all black sufaces are safe for dot viewing. If someone saw that, then focused a 1W+ 445nm laser on, say, a black piece of plastic, that could be very dangerous. If the plastic started to melt, it could become much more reflective causing enough of the beam to reflect to injure your eye.

I don't know why anyone would want to look at the dot without glasses up close. The actual dot (or line) can't actually be seen, and it is usually uncomfortable.

Just to be clear its not like im talking about dot viewing as in im wanting to stare at the dot from 2" away.

Im talking like if dot from a Class IIIB laser is on say my heatsink for my Radiant Electronics X4 LPM and it happens to be in my peripheral vision is that going to be a bad thing? or if I glance at it for a second or two hitting the heatsink if that going to be bad for my eyes?

 

[ChaosLord]

Just to be clear its not like im talking about dot viewing as in im wanting to stare at the dot from 2" away.

Im talking like if dot from a Class IIIB laser is on say my heatsink for my Radiant Electronics X4 LPM and it happens to be in my peripheral vision is that going to be a bad thing? or if I glance at it for a second or two hitting the heatsink if that going to be bad for my eyes?

In this example, I would say not likely. A momentary glance on a surface made to absorb light like the X4's sensor may be uncomfortable, but I don't think you are likely to do any real damage.

Same with peripheral vision. Since you're eye is not focused on the source, anything short of a direct beam would be hard pressed to cause damage. Unless of course the laser is several 10s of watts more than anything we have in handheld..

 

[Rifter]

thanks man! appreciate the help as im still super new to lasers.

 

[ChaosLord]

No problem. Glad to see you are concerned about safety!

 

[jessiex12729]

SDLaser 303 small red dot HELP?
I just got my laser today played with it charged it and now It did not work so I opened it up and there is a small red dot and it wont do anything, It seems like that battery wont even fit either lol please help

 

[WizardG]

Retinal injuries are generally painless.

 

[Rifter]

Retinal injuries are generally painless.

that's exactly why im so scared of lasers lol

 

[Rifter]

SDLaser 303 small red dot HELP?
I just got my laser today played with it charged it and now It did not work so I opened it up and there is a small red dot and it wont do anything, It seems like that battery wont even fit either lol please help

im not sure that my thread is the correct location for this but ill try and help.

Do you have a link to the specs of the laser?

What type of battery does it take?

Can you take any pictures of the laser?