# how many mw's does it take to start burning stuff



## bozo

I just purchased a pyxis 30 mw, my first laser and it hasent gotten here yet and i was wondering if i could burn stuff with it at all or at least pop balloons


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## Athoul

From my own experience I find it generally takes about 45-50mW to pop dark balloons with the aid of a black spot. However it might be possible to pop a dark colored balloon from a very close range with a 30mW if you paint a black spot on it for the laser to hit. I havent tried this so I can't gaurantee it will work.


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## LaserFreak

If you put a black mark on a balloon (with a sharpie) you might be able to pop a balloon...I know the red balloons seem to pop easier then other colors...that's about it.


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## nero_design

I think you need to be slightly above 45mW to see the laser actually smoke something. There's just not enough heat otherwise. I don't think a true <30mW will do it but the 30mW beam intensity and the dot brightness looks very similar to the higher powered models. The only thing it won't likely be able to do is burn things. Still, watch out for your eyes: <30mW is certainly powerful enough to be a safety concern if used up close.


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## eric343

40mW of 514nm focused to a spot by a lens will smoke electrical tape.

Use a lens to focus the beam...


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## nero_design

eric343 said:


> Use a lens to focus the beam...


Just be sure not to use an optical device to view the laser and watch for reflections from any glass surfaces.


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## fstower

I've also been able to smoke black tape with a $20 Red 635nM <5mW laser.

I used the final collimating lense from a <5mW green leadlight laser.

Using the same lense on a 45mW green (refocusing for nearby) is insane
don't do it without 532nM eye protection....


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## eric343

Yeah, I have argon safety glasses which I used for the experiment. (the lens was also not particularly powerful)

Doesn't everyone who's playing with lasers this big?


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## totalyfrozen

I have a pot modded leadlight that I can pop balloons with.... I have to put a black mark on it with a sharpie to do it but it works.


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## HZDavid

We test a line balloons by high power laser pointer
about >100mW, this is very power output and all balloons are broken,

David


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## Neg2LED

It's all about the CO2 tubes, man...

50w Carbon Dioxide laaaaaaaayyyyyyyzzzzzzzzzzzzzeeeeeeeerrrrrrrrrr!

I played with one at my friend's dad's place...i can set cardboard on fire from 20 feet away!

it's beam is actually invisible (and as such, normal safety goggles work fine until you burn a hole thru them) so to find out where it's pointing it has a 2mw Helium Neon red laser tube.

long pulses only, it's got a 50% duty cycle (for every second it's on, it needs a second to cool down, give or take) about 20 seconds of on-time is the maximum - it then forcibly cuts the laser power. it's cooled with antifreeze and distilled water 

Gotta love the tubes, man....

not pocket-able, but go get youself a 300mw yellow laser for $1000 and you can burn stuff 

did i mention that this CO2 box of wonders only cost a hundred bux? it's an ex-medical laser...

--neg


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## jkaiser3000

I have a 21mw greenie, and can smoke things with it. I have to focus the beam with a lens, and paint the surface black, but it works. Haven't tried the baloon test yet, only tape and foam. 
Remember to wear eye protection, even at this "low powers" the focused beam is extremle bright and dangerous.


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## Davidgojr

I believe it takes at least 50mW to reliably pop a dark colored balloon.


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## oldlaser

jkaiser3000 said:


> I have a 21mw greenie, and can smoke things with it. I have to focus the beam with a lens, and paint the surface black, but it works. Haven't tried the baloon test yet, only tape and foam.
> Remember to wear eye protection, even at this "low powers" the focused beam is extremle bright and dangerous.


 
Hehehe!!... tried this today using black electrical tape... *smoking at ~25mw*!! It even made a bunch of little holes!! Amazing... THANKS Arnold*!! 

OldLaser

*From AtlasNova


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## freedom

Very informative sharing guys. Thank you. May I ask what is the maximum output power that is safe to our eyes?


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## bootleg2go

Hi Freedom,
That would be about 5mw, anything more can quickly cause permanent damage.

One thing I want to add to this thread about what it take to burn things. It is not the output power in mW from a laser that causes things to burn, but the heat/ light energy being concentrated into a very small area. sure with a typical beam width of 2mm 50-70mW may melt a hole in plastic, but the same thing can be do with a 5 to 7mW laser if a lens is used in front of the laser to make the area the beam 10 times smaller and more concentrated. On the other hand a 500-700mW laser that is spreading it's power over an area 10 times as large in area ( 6.3mm diameter) will only burn a hole in plastic as well as 50-70mW laser with a beam diameter of 2mm or a 5-7mW with a diameter of 1.1mm.
Area of a circle = (Pi*radius^2).

Something to put it all in perspective.

Jack


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## comozo

10mw can produce 30 million watts per sq cm if you...read on.

http://www.olympusfluoview.com/theory/confocallaserintro.html
It is important to note that extremely high power densities are achieved at the focal point of a concentrated laser beam. A 10-milliwatt beam focused to a diffraction-limited spot 0.22 micrometers in diameter results in a power density of approximately 30-million watts per square centimeter. Such high energy levels can rapidly degrade or destroy lens and filter coatings, as...

like Bootleg2go said it all depends on the beams diameter.


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## Davidgojr

freedom said:


> Very informative sharing guys. Thank you. May I ask what is the maximum output power that is safe to our eyes?


 
I believe the U.S. military uses up to 25mW green lasers on weapons. Despite this, I would use extreme caution with any Class IIIb laser.


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