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Beam stopper?

steve001

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I don't think it's a good idea to use any kind of glass beam stop not even a lens unless the whole system is bolted down, if it's not bolted down then it's a reflection hazard.
Well take precautions.
 



RedCowboy

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Well take precautions.
Like NOT using something made of/from glass as a beam stop.......my point exactly, and you should know this.
Again I say if the system/train is bolted down then a glass beam stop could be set up with safety glasses on and then observed later, but to work with a train where the beam stop is potentially reflective is .........well I will be nice and say it's simply not a good idea.

Try to remember our readers are often beginners working with a new ebay laser and telling people who may not be wearing laser safety glasses to use a glass beam stop is reckless, however a brick sitting by the wall at the end of the workbench that's targeted again and again as a beam stop is a reasonable suggestion, why even use a lens? Why introduce the added risk ? You didn't mention that said lens should be AR coated, I have seen many a random lens reflect a substantial beam even when aligned when they are not AR coated.
 
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steve001

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Not 100% sure but I think what Steve had in mind was to focus the laser to as fine a point as possible for burning at a range of a few inches. Focused that way the beam would then diverge rapidly away from the 'work' area.
Thanks and sorta right. But what I had specifically in mind is this. After the beam has passed the working distance allow it the pass through a negative focal length lens so it diverges rapidly to lower the power density to a non hazardous level. It will likely be hard to find a single lens for that purpose so two or more lenses glued together will be practical.
 

steve001

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Like NOT using something made of/from glass as a beam stop.......my point exactly, and you should know this.
Again I say if the system/train is bolted down then a glass beam stop could be set up with safety glasses on and then observed later, but to work with a train where the beam stop is potentially reflective is .........well I will be nice and say it's simply not a good idea.
I'm assuming the person is smart enough to realize all you've written.
 

RedCowboy

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Thanks and sorta right. But what I had specifically in mind is this. After the beam has passed the working distance allow it the pass through a negative focal length lens so it diverges rapidly to lower the power density to a non hazardous level. It will likely be hard to find a single lens for that purpose so two or more lenses glued together will be practical.
How the hell are two or more lenses glued together that you must align with while working more practical than a brick that you simply target ?
 
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Unpairedelectron01

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In my opinion the best beam stop (if you want to put in the time to make it) is a stack of razor blades in some sort of housing. The edges of the blades trap light very efficiently and there is almost zero reflection. It also resists very high powers, probably 10W+.
 

steve001

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How the hell are two or more lenses glued together that you must align with while working more practical than a brick that you simply target ?
I mentioned it as a workable alternative method.
 
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hakzaw1

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Hello,

what do you want?. Do you like to see the focused beam on a target or do you want to absorb all the light on the target? In this case I would suggest to use a black box with black velvet inside and a hole at the target side.


best regards

Edgar
Have you actually tried this ???

BLACKVELVET??

Black stuff burns faster--velvet is CLOTH--I cannot agree that any cloth make a good beamstop...especially BLACK..
untested advice is NOT a good thing...

hak
 
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GSS

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Have you actually tried this ???

BLACKVELVET??

Black stuff burns faster--velvet is CLOTH--I cannot agree that any cloth make a good beamstop...especially BLACK..
untested advice is NOT a good thing...

hak
Thats the first thing also that popped into my head about the velvet and being black on top of it..
Steve001, the OP is pretty new and asked for a simple beam stop.. Yes he's a bright individual as far as his posts but for him to start a build of setting up a lens system to expand the beam to a safe width, right past his work space is a bit silly for now..????

I found the back non glazed side of bathroom tile in a 4 x 4 inch size or 12 x 12 inch does well or any other sizes they might come in..
 

steve001

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Thats the first thing also that popped into my head about the velvet and being black on top of it..
Steve001, the OP is pretty new and asked for a simple beam stop.. Yes he's a bright individual as far as his posts but for him to start a build of setting up a lens system to expand the beam to a safe width, right past his work space is a bit silly for now..????

I found the back non glazed side of bathroom tile in a 4 x 4 inch size or 12 x 12 inch does well or any other sizes they might come in..
I know and now he has another method. For all we know he may not have a brick or similar item available, but they might have a negative elf lens. Suggesting many methods isn't a bad thing.
 

RedCowboy

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I have used a length of PVC pipe in front of a cinder block before, that way AFTER it's all set up and secured I can view the beam without the bright spot at the termination, just a nice diffuse glow from the pipe, it's all about the angle of view and obstructing your direct view of the termination.

65134

I know and now he has another method. For all we know he may not have a brick or similar item available, but they might have a negative elf lens. Suggesting many methods isn't a bad thing.
Suggesting something reflective without mention of the fact that your " cluster of lenses glued together idea " poses a reflection hazard indeed sounds like a bad thing..........along your line of thinking why not a mirror to bounce the beam somewhere safe ? Because a reflective beam stop is not a good idea, not as a ready made point and use beam stop, your idea is not good as a general use beam stop, rather it's part of an optical train.
 
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GSS

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I know and now he has another method. For all we know he may not have a brick or similar item available, but they might have a negative elf lens. Suggesting many methods isn't a bad thing.
True, the more info the better.. Spreading the beam wide while in use or before shutting down a laser for the next time is good precaution..

Red, a few year back I got a 10 inch tube made for concreting post's into the ground, and glued one end to a 12 x 12 bathroom tile.
I painted the inside of the tube and the back side non glazed part flat back. For two reason's, for the beam stop and the to see the better..
My cat ended up making it her hangout and it ended up a chew and scratching post:whistle:
 

RedCowboy

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LOL, Yea but we love our fuzzy faced fleabags. No doubt that your cat probably thought you made it for him/her. :D
 

reloader45

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Hello,

yes, I tried the black Velvet at distances of 5m ore more with a 1 W green laser. Sure, it is no option for power laser. In this case you risk a burn.

I must try the black anodized Aluminium. It should also look nice at my Aluminium heatsinks.
Has anybody experience with DIY Aluminium anodizing?

best regards

Edgar
 




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