Laser glass tube

Hello there
Is the laser glass tube supposed to be full of liquid when printing?

Yes, that is your coolant.

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Can you see the liquid through the tube? because I see it empty

You will not see the liquid unless there is an air leak in the tube. (Aside from when you first turn it on, you might see a few bubbles that will dissipate. It’s a closed system. Looks completely empty when it is full.)


I made an impression today and I did not see bubbles nor can I see the liquid

It does not have any liquid, what can I do? I need to print and I do not want it to be damaged. yesterday the yellow light of the printer came on, that could be caused by the laser tube. or has coolant

If the yellow light went out, just run a job as usual. you can’t always see the liquid, but it’s there.

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Not long after I got my first GF, I realized I couldn’t see any liquid in the tube and freaked out. I knew I had ruined my system by running it without coolant! But, some nice person (pretty sure it was @Jules ) set my mind at ease. Whew!



I’m so sorry to hear your Glowforge laser tube looks like there is no fluid in it.

Like @Jules said it is normal to not see any movement of the fluid in less there is an air leak or after moving the Glowforge can create bubbles in the tube.

If you would like to post a photo of the tube I would be happy to take a look for you. I also extracted logs from your Glowforge and it looks like it is running correctly.


If there’s no coolant in the tube, heat will quickly kill the laser. If you’ve run any reasonably long (more than a few minutes of continuous lasing) job on the printer and it was still working at the end, there’s nothing to worry about, your tube is full of coolant.


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