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Whats that Smoke ?

M

Mosc007

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Feb 2, 2012
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I just had another play with White Paper.

Looks like I have been talking rubbish :)

The problem I had was with the Focus. I have been Focusing it on the wall in the Toilet about 4 meters away. Even with that long Focus it Burnt thru the Black CD case, Cut electrical tape and Instantly lit matches very quickly at a short distance from the laser. I didn't realise how much differance the Focus was at a closer distance to the laser.

I used something that didn't burn at a closer range. Damm, Doesn't the Focus change a lot when at short distances. I Focused it at 6 inches on the test target and now the beam on the Toilet wall is about 12 inches. But up close it's a Pin.

Now with the White paper an Instant Burn straight thru it :)

This is my First Multimode Diode. They certainly are differant to single mode.


Charles
 
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vk2fro

vk2fro

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yes you do need to focus. I just placed a pack of resistors in a white card (glossy), and tried to burn it from a foot away. Incorrectly focussed the laser did nothing, but correctly focussed, the sales pack had a hole in it within seconds.

Get the "stripe"/dot as SMALL as possible on your target.

I focus by aiming and firing, and looking at the stripe through my goggles. I then turn off, adjust and try again. If it gets bigger, I turn off again and adjust in the opposite direction twice as much. When I get it right, its just a tiny pinprick, and I can smell the carboard burning (and so can the smoke alarm!)
 
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cheech226

cheech226

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when my 445 and 405 lasers are focused just right to burn i can see a hint of florescence on the target.
 
Seoul_lasers

Seoul_lasers

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Jul 4, 2008
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Mosc007 said:
Oooops.

I was at a mates place showing him some tricks with my M140 Lab laser.

I had it pointed at a Light Grey wall about 3 meters away. I thought Very Light Grey Paint would be ok.

After doing some CD Case Buring, Lighting Matches etc we noticed some smoke from his wall.

This is a Very Light Grey Paint. It is Plywood underneath. Not Gyprock or Drywall.

We had a close look and their are 2 Burn marks in the Wall. Both are several mm Deep.

After seeing it burn the Painted Plywood we tried on another peice of unpainted Plywood. It Burns thru the first layer of Plywood in a short time. When it gets to the second layer it stops burning. The second layer must be harder wood.


Looks like you gotta be carefull what color Paint you point it at. Even Very Light Grey Burns. And this is only running at 1023ma.


Charles
Click to expand...

yup... even though you're dealing with a multimode diode, they still can burn "well" at a distance (no where near as good as a single mode) You should see what I did the other day with my DTR 2.7W build!!
445nm can and will burn just about any colour of flammable material as long as the beam beam width is smaller than about 30mm.
 
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