Instructables
Picture of Replacing a CO2 laser tube
SAFETY FIRST - Lasers are dangerous, I'm assuming you know this and you know what you're doing with lasers and soldering irons. Never run a laser tube outside of the laser-chassis, never defeat any safety systems built into your laser cutter!

The CO2 laser tubes found in many laser cutters/engravers only have a lifetime of around 1000 - 2000 hours, after which they need to be replaced.
While replacing the tube for the BuildBrighton Hackspace laser, I thought I'd document the process as there's not a huge amount of info out there!

Tools required:
   Craft knife (for cutting silicon tube)
   Soldering Iron & Solder
   Screw drivers (for releasing laser tube clips, exact driver depends on laser).
   Wire strippers
   Wire cutters
 
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Step 1: Detach old tube

Picture of Detach old tube
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The laser tube will be soldered on at each end. The points where the wire is soldered may be covered by insulation tape, silicon sealant, heat-shrink etc. Ours was covered by silicon tubing & sealant.
Cut back the covering until you can see the wire & solder. Heat the solder with a soldering iron while pulling gently at the wire, it should pop off. Repeat for both ends of the tube.

Pull the water-supply pipes from each end of the old laser tube, if they are very tight you can chop them off as long as you've got enough slack in the pipe to make it to your water container still.
There will be a couple of clips holding the tube into the laser-chassis, undo the clips and lift out the laser tube.
Robomods1 year ago
The silicon sealant needs to be replaced which seems to be missing in your tutorial.

I was wondering WHY? If everything is soldered on and thermal shrink tube is used to isolate, than I can't understand why that messy silicone is needed. I see it in every guide to laser tube and I cannot see other use than as an isolator. Can You tell me what it is for?

The main use of the silicone is to stop the terminals corroding over time as it forms an air tight seal unlike heat-shrink tubing.

The silicone also acts as an insulator helping to stop arcing.

thanks for posting, just a question how do you know if the laser tube is fried, and not some other fault like the driver. and whats a tube worth?
tubfun (author)  liquidhandwash1 year ago
Good question liquidhandwash.
It's really quite hard to determine whether its the driver board/power supply or if its the laser tube.
In our case we knew that we'd been using the laser for a long time & the tube was almost due a replacement.
The symptoms we were seeing were reduced power - it was taking as long to cut through paper as it used to take to cut acrylic, and a quick drop off in power - the laser would behave normally for around one second, then power would reduce dramatically.

The tubes themselves can be bought for around £170 - £230 for our 40w laser. Ours was purchased directly from china.
Thanks I have a laser that is very similar so good to know
fred271 year ago
Very well documented, thanks. I hope I don't need to follow it but it's good to know your guide is here.