HOWTO: Glue the glass lid back in place

A few years ago I got some experience gluing my glowforge’s lid back on.

Since then, I got a new (to me, refurbished) unit (to replace the laser tube), and it worked great for a year, but then I noticed that the hinge on my new unit was separating from the glass. Since my refurbished unit was out of warranty, I figured I’d fix it myself and record a video in case anybody else wants to see how I did it.

https://www.summet.com/blog/2022/02/19/gluing-the-glass-lid-back-on-my-glowforge/

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I’m sure this will be very helpful!!

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This is good to know stuff… Thanks for sharing.
It appears that your machine was wobbling a bit when you pushed down on the back of the glass. Could that be why your repaired lid was not closing completely flat because you need to level the GF a bit?

I had pulled it out sideways a little bit to take a photo of the serial number on the back plate just before gluing. However, even after I put it back in place the left hand side was slightly tight, so I’m going to say that the lid “torqued” a very small amount from being glued in the upright position. I think if I have to do it a third time, I’ll go back to the “lid flat held down with rocks” style so that I can align the front in the center from a left/right perspective.


(Note that this photo shows an E6000 adhesive package which I tried previously, but it didn’t work out so I had to re-do that glue job with Epoxy…so don’t try E6000…]

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In all the years we’ve seen this, you would think they could have suggested an adhesive. I assume they are using some bulk industrial product but they could at least have shared what consumer product would be similar.

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With the influence the FNLs have at GF, surely you jest :smiley: Anything with even a whiff of potential additional liability beyond what is the minimum necessary to sell a product like the GF is to be avoided at all costs.

I also expect they have been changing the adhesive formulation over time as they see the performance in the real world and what’s available in the market.

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My Glowforge lives in a “minimally conditioned” space (i.e. the heater is set to keep it above 60, and the AC is set to keep it below 80, but it’s free to swing between those temps) so it may experience wider temperature swings than some. This may cause the glass to expand/contract at a different rate from the metal it is glued to, which may be why each of the two units have both shown this type of failure.

I’ve used JB Weld Clear (I think it might have been the 20 minute type?), and (this time, Loctite brand clear 5 min epoxy). On my past unit I had to glue the handle to the front of the glass and the glass back to the hinges (both with the JB Weld). Both of those connections lasted as long as I had the unit (2 years and 1 year) before I swapped it out for a refurbished unit for the replacement laser tube. We’ll see how long this current (Loctite clear epoxy) one holds.

(From examining my first Kickstarter unit, my best guess is that they also used some type of Epoxy on it).

The only other adhesive I might consider trying would be a “windshield” or “auto-glass” urethane such as Dow BETASEAL U-418 HV. (But that stuff costs a lot more than epoxy…and comes in GIANT tubes…)

The Betaseal has the advantage that it is a bit flexible and hopefully temperature swings wouldn’t be an issue for it, but I’m not sure there is enough contact area for it to be strong enough on the hinge side of things. Like I said, the epoxy has worked for me in the past, so unless this guy comes off before I have to replace the unit for a new laser tube, I’ll probably stick with it.

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I am thinking about doing this as well. Mine arrived with the front handle detached. It is clear the epoxy failed. I got an email last week saying they would replace my unit but since them crickets. How hard can it be to just epoxy it back in place. They are so slow I am eating up my warranty without actually having used my machine even once.

I can’t recommend that, as you are under warranty. Might be time to ping them again.

I ping them. I get a response saying they are sorry that its taking so long to get back to me. They will get right back with me to get a replacement shipped out. Then crickets. Been through that loop 3 times now. Also told me that my warranty is till running so I will have less warranty even though I never even got to plug in the machine. This is crazy. I get being behind but contact systems exist that help keep customers informed. Its not that hard.

The unfortunate truth is that support has no idea when a machine will be available. Communication with the different outsourcers that have assembled/now refurbished them is very poor, always has been, and support typically won’t contact you until they have information to share.

The warranty issue is equally frustrating. Sorry.

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