The only time the exhaust fan should be disabled is if your external fan is at least as powerful as the one built into the machine, and only then if you have a short duct run with two or fewer bends.
The average shop vac is <<100CFM. The largest are less than 150. The machines exhasut fan is just under 200. So putting a shop vac inline is actually restricting airflow, and certainly not capable of evacuating the machine as intended.
A shop vac is not a suitable means to remove smoke and odor from the machine, and should not be used even in conjunction with the built-in fan.
I agree with you. Perhaps you missed his comment at the beginning that says “I have an external inline fan”. He was using the shop vac only to clean the fan/grill.
The inline fan is there to help exhaust the Glowforge. The Glowforge sits in a basement and the air pumps up through the venting. This is not to replace the glowforge exhaust fan but to help it get the air out of the ‘last mile’ of venting. The inline fan is basically at the point at which it exits the basement. The inline fan is working and does create slight negative pressure but nothing like the Glowforge fan.
Mind you, this has all been working fine until yesterday.
I have finished an initial cleaning of the fan, but it was not a thorough cleaning using the degreaser. I am waiting for that to arrive. Should arrive Friday, I will let you know after I follow the Glowforge fan cleaning instructions.
Bottom line is this: if the exhaust fan(s) are functioning adequately, the pressure in your Glowforge will be lower than in the room. No smoke will come out - only room air will flow into the Glowforge and out the vent. I always still wonder about tightly sealed homes and having a couple of bathroom fans running. If the house is at lower air pressure than outside it becomes very difficult for a fan to exhaust out of the house. Maybe try opening a window somewhere else in the house not near your Glowforge vent.
That page will walk you through the cleaning process. Brief summary:
Turn off and unplug your unit and move it outside. Make sure it’s in a location where it has power and Wi-Fi
Using the fan maintenance page, you’ll be able to turn the fan on
Following all manufacturer’s safety instructions from 3M, spray the degreaser into the fan while it’s running for approximately 5 - 10 seconds, or until the fan is clean.
When you’re done cleaning, turn off your unit to stop the fan, and return it to its usual home. You should now see considerably better performance from your exhaust fan!
Please let us know if you have any questions!
Other than that, I need to say:
Your Glowforge is designed to operate with the included exhaust hose connected to the outside with a maximum of two 90 degree bends or to your Compact Filter with a maximum of three 90 degree bends. If you configure your exhaust differently, the Glowforge unit may not be able to expel enough air, and it could cause smoke and fumes to enter the room. Because ventilation is complex and poor ventilation could cause smelly and even dangerous results, we can’t advise on exhaust configurations other than what’s described in the Glowforge Manual at Glowforge - the 3D laser printer.
If you do want to configure your exhaust differently, there are some great resources on the forum that can help. You can post in the Beyond the Manual section of our community forums to see if the community has suggestions: Beyond the Manual - Glowforge Owners Forum. Note however that advice in this section is unsupported and is not reviewed by Glowforge.
Regardless of how you configure your exhaust, please follow these instructions from the user manual to avoid a serious safety hazard: “There may be some odor present while printing. However, if you detect a strong, sharp smell that also causes eyes, nose, or throat irritation, or if there is visible smoke escaping while the lid is closed, stop immediately and re-check your exhaust setup. If the irritation and/or smoke emissions do not abate, discontinue using your Glowforge and contact support.”
I’m going to move this thread over to beyond the manual. If you need more help troubleshooting from support, the next step would be to remove the inline fan, and configure your exhaust according to the manual.
There was a time when I had exhaust issues before Glowforge was selling their filters and I got a Blu-dri that is designed to move over twice as much air than the Glowforge with HEPA filter and carbon filter. I never got the connection from 4 to 12 inch, but just set running in the room it would clear the smokey room in minutes. it even clears the house of cooking smells,
Draftboard is by far the dirtiest material you can cut, oak is a distant second, Acrylics will eat up the activated carbon filter faster but is much lighter in terms of particals.