40W handheld laser cutter

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Martin Raynsford has written an article detailing his 40W handheld laser cutter:

To generate the high voltage required to start lasing within the tube, I connected 200x 9V ‘dead’ batteries together, this generates nearly 2000V across the laser tube. I’ve been collecting these batteries for months, you can use old batteries for this because they only need to provide power for a fraction of a second, this is enough to generate a short pulse of laser light.
Normally the input would be switched at 2Khz to generate a continuous output from the tube, but making a switching circuit from a DC power supply (a battery) involves some complicated electronics, this stack of 9V batteries is a quick way to produce the high voltage, low current required to activate the tube.
Even with these short pulses of light the tube can heat up quickly so I installed a small 6W water pump to push water through the cooling jacket. The pump is not very good at drawing a vacuum so the reservoir was stored above the pump so it could gravity feed. The pump was powerful enough to push a sensible amount of flow around the tube and back into the bottle.

Project info at Just Add Sharks site.

Check out the video after the break.

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12 Comments

  1. A bit light on details… I suppose it’s a CO2 laser tube, looks the part, seems to be a widely available spare part of some sort. Is he using safety goggles? Okay, I think I’ll gladly leave this kind of fun to these guys…

    1. The gloves are a precautionary measure to protect his hands from burns in case the water-cooling fails (after all, it’s a prototype)

    1. Ah, we were had, see the last sentence.
      Good job, fellas like me wanted to believe this thing can be done, so like all great gags, the victims fooled themselves. Pretty good acting. I did thought it was possible for Americans to perform this stunt without safety goggles :-P
      We geeks/nerds must want sharks with lasers really bad…

      1. Yep, we got you, sorry about that.

        While it might be possible to actually do this and I would happily do it without safety goggles on, the main reason I wouldn’t do it is for fear of touching the high voltage tube. I’ve had a few day to day shocks and they’re not pleasant, waving this thing around is just asking to get a serious shock. (maybe if the whole thing was enclosed and I had earth spikes in my shoes? )

      2. Ha ha, yeah, it’s better than the usual pranks, a bit like Ghostbusters you know, back when movies didn’t dumb down dialogue.
        I wouldn’t know enough about this field to make a determination about goggle requirements, but I have seen pix of animals’ retina with tiny black spots taken during safety testing or something of low power lasers, so I have my paranoia dialed up to 11.
        Searching ’40w lasers’, I was entranced by the spare parts on sale… looking forward to future vids. The 40W rating reminded me of “…phased plasma rifle in the 40 watt range…” ;-)

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