Alert Cooling Issue - WARNING - Blown Tube

Hello all,

First off, I’d like to mention that this post is in no way an attack on Glowforge support as I have just informed them yesterday of what happened to me and am awaiting a response as I post this. This post is a warning for all Glowforge Basic users that may encounter the same issue I had.

Some of you may remember (@jbmanning5, @Jules, @CharlesDarwin) that I was having some cooling issues about a month or so ago. Please read this post if you are getting the “Alert Cooling” yellow light and you know your ambient room temperature is below 75 degrees.

Well, I have been in contact with the support team via email and have been slowly testing different cooling methods in order to make sure my glowforge is operating in the correct ambient temperature. The last “fix” was to remove my duct prior to any laser usage in case any of the outside air were to fill the Glowforge during down time, thus heating it up before use.

This weekend I finally purchased a window A/C unit specifically for my Glowforge room and turned it down to 65 degrees, I live in South Texas and know that it can get hot outside, so this was a final effort to keep the room at a steady 69 - 70 degrees before operating the laser. I wish I could say this resolved my issue, but alas, it did not. I was able to run one job (20 minute cut file on PG acrylic) and I received the Alert Cooling message again. I decided to shut down the machine, emailed Glowforge support, and waited for a couple hours to cool down. I had one more job I needed to run for the day (and thought it would be another good test with the window unit cranked up) so I fired up the Glowforge again for one more run last night. The job started just fine, and since it was another 20 minute cut file, I figured it wouldn’t have any issues mid-cut… then this happened:


This occurred within about 5 minutes of my cut job. After the initial shock, anger, then sadness, I realized how lucky I was that this damage was contained within the Glowforge. I was sitting about 5 feet away and can’t explain how scary it was to hear the pop, then see the glass shattered everywhere within the unit. I have emailed support my pictures and story and am currently awaiting a response, I will fill everyone in once I receive one.

PLEASE use this as a warning. All of the signs pointed to something wrong with my coolant pump within the unit, yet I was continually told to keep testing. I also noticed several coolant pump errors in my error log (that was sent to support). If anyone is getting the Alert Cooling issue regularly and the ambient temperature around the glowforge is below 75 degrees Fahrenheit, please refer them to this post to make sure you won’t end up with the same result.

Sorry for the lengthy post, hope to have this resolved quickly.

Thank you,

Holden Linder


Oh that’s too bad. We’ve seen a couple of other bad tubes reported here on the forum that popped. It’s very rare. (And as you noted, the design of the machine is set up to contain the damage, for which I’m also grateful. Never know when something like that is going to happen.)

Don’t worry, Glowforge will get you fixed up, and it wasn’t anything you did. :slightly_smiling_face:

Just out of curiosity…how did the gantry get knocked askew like that? Did it hit something? Or did the bulb popping knock it off the track?

You know, I’m really curious as well. It happened so fast, that I’m not sure which happened first. I can only guess that either the bulb popping knocked it off the track, or maybe one side of the gantry locked up and that’s what caused the bulb to pop? I was working with a piece of Medium Red Acrylic, so there was nothing for it to hit. If the servo on one side stopped working and the other kept moving, it may have bent the tube and caused the break as well.

Now I’m wondering if my cooling issue was even related to the blown tube. So confused. I know the Glowforge team will take care of me, I received a damaged unit upon my original delivery and was sent a replacement literally same day, so this would be my third GF. Third time’s a charm?

As always, thanks for the support @Jules.

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Hmmmm. I think I need to check my logs. I had a night where it was 72 in the basement and I got cooling cycles before & during trivial (<10 minute) jobs.

I figured it was heat buildup inside the GF and have taken to leaving the lid open & the blast gate closed when I’m not using it.


Your luck does seem to be pretty sucky there. Maybe you should consider buying some lottery tickets going forward, because the universe has a way of balancing things out over time. :wink:

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Time to go to Vegas!

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It’s likely that broken glass was trapped under one of the gantry wheels, causing that side to be stuck while the other side was able to keep moving.

Highly likely that it was due to the cooling issues. The gantry can go askew without causing any stress on the tube, as the gantry itself is fairly rigid.


So not only do they ignore the air assist fan not spinning, they also ignore coolant pump failure despite logging it. Out of 50+ sensors they only seem act on the door sensors and the coolant temperature. This is after at least 3 years of development and a year of production. Unbelievable.


Oh no! I’m so sorry to see that happened.

Let’s get you a replacement unit right away. I’ll be in touch via email to sort out the details.