# how many mW does it take to burn something?



## Shredhead (Jan 28, 2005)

how many mW does it take to burn something? i saw the video on laserglow.com and was curious as to how powerful it was.... mW?


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## jonesing4wind (Jan 28, 2005)

I have a high 30s pen style unit, and can go through a black plactic radio shack bag. I cannot feel any heat on my hand, even on more sensitive places like my forearm. It is very bright, and lots of fun. I think for a first unit, this should be about the max power I would recommend. Plenty bright to see beams and have fun wiht, but not quite as dangerous as more power. This recommendation is from a complete novice, and of course no laser is completly safe.....

sean


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## 4sevens (Jan 28, 2005)

90mw will smoke black tape instantaneously. at 2seconds it will
penetrate the tape /ubbthreads/images/graemlins/smile.gif


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## jtice (Jan 29, 2005)

52mW does rather nice on black garbage bags /ubbthreads/images/graemlins/grin.gif
http://www.jtice.com/home_movs/laser/Burning%20Garbage%20Bag.AVI

Only real dark colored, or black things will burn,
you cant feel this one on your skin either.


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## K-T (Jan 29, 2005)

The thing I am wondering about is if eventhough you don't feel anything you could damage certain tissues of your skin with a laser? I don't know what kind of wavelengths are filtered out or not though? /ubbthreads/images/graemlins/icon3.gif

The conclusion that it won't make any damage just because it doesn't hurt _could_ not be right. That's only a wild guess.


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## Bond007 (Jan 29, 2005)

[ QUOTE ]
*Shredhead said:*
i saw the video on laserglow.com and was curious as to how powerful it was.... mW? 

[/ QUOTE ]

The video on laserglow is a >50mw model so it's probably somewhere between 80 and 95mw


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## 4sevens (Jan 29, 2005)

[ QUOTE ]
*jtice said:*
52mW does rather nice on black garbage bags /ubbthreads/images/graemlins/grin.gif
http://www.jtice.com/home_movs/laser/Burning%20Garbage%20Bag.AVI

Only real dark colored, or black things will burn,
you cant feel this one on your skin either. 

[/ QUOTE ]

It's all about energy absorption and heat dissipation and
divergence of the beam.

Darker colors will absorb more "light"
and certain materials will disspate heat better than others.
Also, ambient temperation matters too.

If you have an infinitely small dot, you theoretically can burn 
through anything with 5mw /ubbthreads/images/graemlins/smile.gif

eletrical tape and black trash bags work well.
I've tried tires and they don't burn - simply because
tires are designed to dissipate heat so they don't melt
at high speeds

I haven't tried this, but I bet it will work with someone with
50mw+ laser - use a permanent marker and mark up a part of your
skin. put a second layer after the first dries. And then laze
yourself. I bet it would burn.... ahem... do at your own risk.


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## LaserMod (Jan 29, 2005)

A red marker works best... use a 25mw+ laser and aim it at the spot. The green dot will turn orange and it WILL hurt. /ubbthreads/images/graemlins/rolleyes.gif But yeah...do it at your own risk. /ubbthreads/images/graemlins/rolleye11.gif


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## photonic (Jan 30, 2005)

Or try it on someone with a black tatoo

Shredhead at the risk of telling a newbie something dangerous, the IR filter of a green laser blocks the vestigial infrared output that comes along with the frequency doubled green beam. Removing it does allow you to trasmit more power and it may increase a given green laser pointer's ability to make small smoking holes in things, but it's dangerous and not recommended.

I wonder, if in the higher power units shown online cutting through plastic bags, tape, etc - if the IR output is as high as a 5mW with it's IR filter removed...


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## LaserMod (Jan 30, 2005)

I did some tests a while back on the heat output of a pointer with or without the IR filter. The results were surprisingly similiar - not worth it if you ask me...and then there's the invisible radioation threat.

I can confirm however that the same dot when viewed through a camera looks noticeably whiter without the filter.

The filter is only there to filter any stray IR that was not absorbed by the crystals. Although theoretically there should be no IR left. If the crystals are of good quality (not alignment) then the conversion will be good and there will be little stray 808nm, as oppose to a dodgy MCA which let through a lot of IR and thats where the filter is added as a protection measure.

808nm +/- 10% from diode > Nd converts to 1064nm > KTP converts to 532nm + Stray IR.

That strange approach image that Spec and Enigmahack did was a good representation of what is happening. It's on the forum somewhere...


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## IsaacHayes (Jan 30, 2005)

they use green lasers to remove tattoos. so yea that would hurt probably. Anyone know what it takes to laser remove hair? Only works on dark hairs and the pores explode sort to say. DIY dangerous hair removale!! I'd do it! /ubbthreads/images/graemlins/sick2.gif /ubbthreads/images/graemlins/duh2.gif /ubbthreads/images/graemlins/caution.gif /ubbthreads/images/graemlins/sssh.gif j/k of course


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## kongfuchicken (Jan 30, 2005)

Why would we use lasers to do that?
Power to "remove hair" efficiently would be more than the power needed to set your hair on fire.
A friend of mine tried to cut cold butter with a 45mW red laser; I did the same with a hot knive and it was a LOT easier...


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## SuperBert (Jan 30, 2005)

no, sorry, there is laser hair removal... look it up... places that offer the service are everywhere where i live now.. shaving seems a bit easier if you ask me


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## kongfuchicken (Jan 30, 2005)

I guess I'm not aware of all the benefits of using a laser; it just sounds like a very complex way to do something relatively simple.
I do remember that sometime ago, the Notre Dame cathedral in Paris was cleaned and restored from its layer of pollution stain using lasers. The use of lasers ensured that there would be no water erosion or chemical damage to the stone walls.


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## IsaacHayes (Jan 30, 2005)

Kongfuchicken: because some of us have extra hair in area's we'd rather not have it in, and would like it gone for good!

I'll leave it at that! heh. But some people do have the laser stuff done on thier face.
EDIT: laser hair removal is permanent. Shaving isn't.


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## kongfuchicken (Jan 30, 2005)

Isaac, I understand. I was just surprised by that use. 
I've always thought that this was done chemically, not with a laser.
There's a gazilion uses for lasers I've never heard of, I guess. /ubbthreads/images/graemlins/blush.gif


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## PhotonWrangler (Jan 30, 2005)

[ QUOTE ]
*IsaacHayes said:*
laser hair removal is permanent. Shaving isn't. 

[/ QUOTE ]

How can a laser reach all the way down to the follicle without frying some of the skin? A follicle is maybe 4-5mm below the surface, I think. That sounds like nothing, but that's actually a lot of skin.


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## Bond007 (Jan 30, 2005)

Plus, laser hair removal doesn't always work permanently.

I saw this woman on the telly who had trouble with a moustache and she tried everything to get rid of it, including laser hair removal. It kept growing back though and she gave up.


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## PhotonWrangler (Jan 30, 2005)

[ QUOTE ]
*Bond007 said:*
Plus, laser hair removal doesn't always work permanently.

I saw this woman on the telly who had trouble with a moustache and she tried everything to get rid of it, including laser hair removal. It kept growing back though and she gave up. 

[/ QUOTE ]

That's exactly my point. I can understand how a laser could take out _a portion_ of the hair, maybe a millimeter or two below the skin, but I can't see how it could reach down to the follicle (which is what you'd have to destroy to stop the growth) without causing damage to the skin itself. In addition the hair would have to be dark enough to absorb the laser light, so I don't think it wouild work on light colored peach fuzz.


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## IsaacHayes (Jan 30, 2005)

PW: You are correct. It only works on dark hair. If you have blond hair/peach fuzz it won't be affected. It works by the dark hair absorbing the light and the follical will heat up and pop out from steam pressure I belive. I think it might hurt the skin some, but not as much as the dark hair. 

You might have to do several treatments, but right now I think it's the best permanent method out there. Eletrolosys requires inserting a needle into each hair follical and shocking it. Talk about painfull and time-consuming! Laser does several hairs at once. I have dark coarse hair so laser sounds nice, I'm just not keen on the price, and I'm not sure what parts of the body they can do it on. /ubbthreads/images/graemlins/icon15.gif heheh

A little back on topic, does the color of the laser have anything to do with it? I would assume that (red, IR) produces more heat, but UV (green, blue) has more energy...

Anyone have a pointer that is Red and Highouput? I've seen some cheap 10mW's before. I'll wait for green to drop in price like Red's did. I remember wanting a red one and they were ~ 60 usd.


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## luckytexan (Feb 4, 2005)

I don't know, I think for burning lasers you neeed >800 nm or the frequency of a CO2 laser. I have one of those pesky ladybugs crawling on my monitor I would like to be rid of /ubbthreads/images/graemlins/smile.gif


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## Bond007 (Feb 4, 2005)

Get the hoover /ubbthreads/images/graemlins/grin.gif


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