I have noticed several post concerning inline exhaust fans. Many complained about cost, noise and the need to convert 6" to 4".
Today I took delivery of and installed a new fan that I purchased on Amazon. The price is fantastic, the noise is about 30db and it is 4 inch. I’m getting no smoke in the house and its quite. Best of all it was inexpensive. Below is a link
VIVOSUN 4 Inch 195 CFM Inline Duct Ventilation Fan Vent Blower
Same one I’ve been using - with really smoky things it sometimes isn’t enough, but you can always turn on the internal one as well in those cases. Quiet enough that I can watch the TV right next to it without adjusting the volume
Ditto for me, very quiet. No smoke issues. Couldn’t believe it at first how unbelievably quiet vs normal.
I have the same fan and was initially disappointed with performance on really smoky stuff too until I taped up all the seams on the fan body - turns out it had been leaking through the housing. Much better now!
I didn’t know you could turn off the internal one.
I have had one for a year and a half as I bought mine when the main exhaust fan locked up and I did not want to ship Puff back in the Christmas rush. Particularly as the main exhaust fan did not spin at all, the Vivosun did a bad job under extreme smoke but I had another that could clear the entire room.
When Puffette arrived the Vivosun moved the air our so fast that there was far less smoke build up anywhere and cleaning less frequently needed. So I use both most of the time but when cutting acrylic late at night I shut the main fan off to cause less noise.
Yup - in your GFUI under the 3 dot menu there is a toggle for “Air Filter Attached”. When you turn that on, it turns off the internal fan (because the Air Filter has a stronger fan than the 
itself)
Thank you. I will have to try it. It sure will make things quieter.
The 4" Vivosun does not evacuate the machine as well as the built-in exhaust fan, so stay on top of cleaning the optics. It is sufficient to keep the enclosure under negative pressure so that no smoke or odor escapes while printing.
I am a total newbie. This is a huge learning curve for me. My husband surprised me with this yesterday and he purchased the external filter since I am not by a window. However, I cut my first practice piece tonite and the filter didnt make any sound at all. I assumed it would make some kind of sound?? There was “alot” of smoke inside the GF while working and I could smell the fumes pretty good. What am I doing wrong? Thanks for any insight you can offer! ******I think i figured it out. yea!
You need to turn it on and turn the dial a bit until you can hear the fan - it’s not on when the knob is at the lowest speed setting. As you use it you’ll notice it’s not clearing the air inside the GF as much and you’ll want to turn the speed up some more until you’re at max and not clearing - then you need a new filter.
Some types of materials & operations (like engraving draftboard) will clog up the filter in only a few hours.
After you use it, leave the filter running for about as long as you were cutting/engraving. So if you used the GF for an hour, leave the filter running for another hour to disperse the residue further into the filter media.
Thanks for the headsup. I’m about to go clean now.
i upgraded to the 6 inch because the 4 inch was almost but not getting the job done. This required a pair of adapters to from from 4 to 6 and then back to 4 but they have those on amazon too.
Mine goes up to 6" at the fan, then stays 6" out the window…
that would make yours bigger than mine…
Sounds like yours is the same, you just chose to choke it down! 
I’m in very unfamiliar territory here, but I just received my unit, along with compact filter. I’m a little overly cautious and want to add extra filtration. Would this work in that situation? If so, how would I attach this fan between the glowforge and the filter?
It won’t aid in filtration if anything your filter could clog faster, but it would aid in extraction. If you put it at the end of the hose rather than the beginning, it will pull the air from the machine and push it outside where the wind will disperse it.
That’s my opinion, I chose to go the inline fan route instead of the filter.
I would not add a fan between the machine and a GF-provided filter.
The controlled airflow thru them is what makes them effective. Forcing it thru at a higher rate would likely cause them to be less effective.
It’s probably why the internal fan is disabled when the filter is in use.
Thank you.