Smoke when printing

I just got a new filter. I am cutting some wood and this is what’s coming out the front? Any advice?
Here’s a video: IMG_0232.MOV - Google Drive

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If you are operating your machine on the carpet shown in some of those pics, your air intake (which is underneath the machine) is almost certainly blocked.

The machine needs to be on a flat, solid surface.


The exhaust hose looks like it is making more turns than necessary so if you make it as short and straight as possible and few sharp bends you may find it moves the air better. There is also the possibility that you are filling the filter and that will also cause the symptoms


Thanks, I shortened it. Also, " filling the filter" - it’s a new filter, or is there something else you might be suggesting that I am missing?

Oh, good to know. I just placed very strong cardboard underneath, which has elevated it. Fingers crossed!

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Here are three new videos, after I did the above. You can see the smoke coming now out for all sides - one video shows the front left, one show the back left, and one in case of use to anyone from above.

Is the filter turned on all the way? You usually start out low (enough so the smoke is evacuated) and then turned up as it fills up and stops pulling enough air. For this though turn it all the way up so you can be sure it’s working.

Also, if it’s not “brand new” but maybe only a few hours of cutting something like MDF it may be full. It can fill in anywhere from a month to a day depending on what you’re cutting.


Thanks James. It is turned almost all the way up. I would hate if it filled up that fast - they are so expensive!

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Indeed. That’s why mine is still in its box. There is a chart they came out with to provide estimates on how long the filter will last. MDF (which includes PG plywood as it has an MDF core) is the worse.

If you can toss the hose out the window for a test you could turn the GF’s fan on again in the UI and see if that clears up the smoke. Then you’ll know that the filter is full.

People have done some things with pre-filter pads they put on top of the filter to provide longer life. If it turns out the filter is full, you can do a search and find some possible ways to get more life out of them.


Good idea. Thank you!

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Looking at your pics your exhaust fan is pretty gunked up, is air able to get through there to the filter?


Exhaust fans work ok even that gunked up but if the fan is like that, the filter is full.

If it is reasonable to run out a window the filter is superfluous.


That might be from an earlier filled filter. Should I clean the gunk off, inside and out? Any instructions anywhere for that?

Okay, here’s a new video. So far I have raised the printer by putting it on firm cardbaord, shortened the length of the venting tube and made sure there are less than 3 bends, and cleaned the fan. It is now no longer coming out the front, but where the filter hose attaches to the back of the GF you can see a lot of smoke coming out. I reattached the hose but no change. Next I will try to vent out the window and see what happens. Thanks for all your help so far! I have a party in Feb that needs 100 invitations!

I’m sorry for the recent trouble with your unit’s exhaust. I wanted to share a quick reminder from our manual regarding scenarios like this one:

When your Glowforge and Filter are properly set up, you may have some harmless odor during printing which will rapidly dissipate. You may also smell something when you open the Glowforge lid after a print is complete. This is not harmful.

However, if you notice a strong, unpleasant or irritating odor when printing, or see smoke, shut off your Glowforge unit immediately. Smoke and fumes could be entering the room in excessive concentrations.

Based on everything you’ve tried so far, the cartridge might be full. Would you be able to take a photo of the cartridge that is closer to metal grille:

Inside you should be able to see a surface that looks like pleated fabric. A clear photo of those pleats can help us check if the cartridge is full.

There are a lot of factors that go into the lifespan of your cartridge. Some of those include how often you print, the designs you print, cutting versus engraving, and whether you follow the directions in the user manual for proper operation. For that reason, it is difficult to predict how long a filter cartridge will last.

To estimate, we tested Proofgrade materials with a standard Glowforge test print. It is 11 minutes long (the average duration of a Glowforge print, and is a mix of cutting engraving that reflects typical usage). If used only for cutting, cartridge life may be roughly half as long. If used only for engraving, it may be more than twice as long.

Note that we have only tested, and can only recommend Proofgrade materials. Materials from other sources may work just as well, but some materials may clog the cartridge almost immediately. For example, MDF products (including Proofgrade Draftboard) will dramatically lower your filter cartridge life.


Test prints before cartridge change

Medium Proofgrade Hardwood (Maple, Cherry, etc) (1/8") (0.3175 cm)


Medium Proofgrade Acrylic (1/8") (0.3175 cm)


Thick Proofgrade Acrylic (1/4") (0.635 cm)


Medium Proofgrade Plywood (1/8") (0.3175 cm)


Thick Proofgrade Plywood (1/4") (0.635 cm)


Medium Proofgrade Leather


Also, as described in the manual, running air through your Glowforge Air Filter will prolong the life of the cartridge. For best results, leave it running one minute for each minute that you print. For example, when you finish two 30-minute prints, leave it running for an hour after they finish.

Our team will watch for the updated photo of your cartridge and we’ll be happy to take a look!

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Thanks! A photo like this?

That looks full/used up to me.

You can fill up a filter cartridge in just a few hours of printing. You’ll note they don’t provide exact numbers for MDF (“Draftboard”) but one owner managed to do it in the first day. “Medium” ProofGrade plywood has an MDF core and will also fill it quickly, as pointed out on the specs page and in the support post above.

If that’s what you’ve been cutting, I suggest you find a way to vent out a window. The filter (and the $250 replacement cartridge) is a last resort.


Thanks eflyguy. That’s just crazy. Have you seen anything one can buy - or print - to put into a window (like an airconditioner), so I can close it down and stick the tube out of it?

Oh, and when you look at the photo what do you SEE that tells you its full. If it was not full what would it look like?

I vented out the window and it worked just fine. I can’t believe I filled up my filter so fast, given what it costs. Last time I use one of those! I just wish I figured this out BEFORE winter arrived. Thanks everyone!

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