Can you clean the inside of the laser window


My laser window (the one with the silver casing on the side of the carriage) developed a crack, so I ordered a new one.

The replacement arrived, but it has a smudge on the inside, the part that faces away from the bed. The Glowforge instructions say to wipe the front of the lens to clean, but they don’t say if the inside or back can be cleaned. I don’t want to ruin any sort of coating it might have so I wondered if I could clean it.

I emailed glowforge to ask, and their response was that they didn’t know and I should ask here. So that is what I’m doing.



You can but be very careful. You can pot drop of alcohol on the smidge and let it soak then use a Q-Tip soaked in alcohol and don’t scrub very hard or you will scratch the lens.


Welcome to the community!
I have cleaned both sides of the head window with a lens cleaning wipe with no issue.


This makes no sense.

They told you specifically to ask in beyond the manual? Is this not an official Glowforge part?

If it’s a Glowforge part and support@glowforge told you to come here something is wrong there.


Yeah, I’m not too happy about it, tbh. #1 sending me a window with a smudge, and #2 no, ‘sorry we sent you a window with a smudge for full price replacement part’ and, #3 we don’t know if you can clean it. Ask at Beyond the basics, but we’re not responsible if anything goes wrong, :confused:

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I can’t remember how to specifically reply to each person, but thank you for your answers!


To reply to a specific user you type “@” and their username, no spaces.

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@PrintToLaser Thanks!


:grin: Spend some time with us and you will find this community the best accessory for your glowforge!

You were wise to be cautious with the optics. I’m not sure if the windows have any optical coatings, but the focus lens and the mirror do, so using lens wipes made for that are recommended.

@PrintToLaser Right, so I’ve worked enough with specialized microscopes in my past scientific life to know that coatings can be fragile (and essential). It’s not like these windows are super expensive, but I know if I mess it up I’ll have to wait for another replacement, lol. They were sold out by the time I got mine in the post, so even if they’d offered to replace it I’d have to wait for ‘new’ ones to come in.

Edit to add- I see you are a Navy Vet. Thank you for your service. My dad was Navy as well. Retired with grandkids now too! But he does photography rather than lasers. :slight_smile:


Thank you! It was an honor, and probably the best thing that could have happened to a young undisciplined fool.


Hmm this is not cool. Glowforge should be answering this. I’d raise a stink.


But they did answer: “We recommend to carefully reach over the rail and and wipe the laser window…” They also said that it’s not part of the normal cleaning, and suggested they ask if anyone here had any advice. Nowhere in the reply shown did it say “we don’t know.”

They should answer it definitively.

It’s their part and their machine, they should know it inside and out. If this were an aftermarket part sure cut them loose but that’s not how it is.

Don’t sell us a part to install on our own and punt on the questions that arise because of it. Bad form.


It’s not part of normal cleaning, but they sent me a window with a big smudge on the inside. Right in the middle. If I don’t clean it it will reduce the transmission of light through the window. They should be able to tell me if cleaning the other side will damage the material. They are the ones who should know. And if it will damage the material they need to send me a window that’s clean.

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If you still have the cracked one, test on that. I’d recommend gentle wiping with a microfiber lens cloth dipped in either alcohol, or a mixture of 50/50 vinegar and water (What I use, and it works fine.)

The window likely doesn’t have any special coating on it. I regularly wipe even my lens with this mixture and it’s three years old and working just fine.

If you damage it, they’ll replace it no doubt, but give it a try on the broken one before worrying too much about it.