If you follow the conversation, instead of selectively quoting one part of my post, you’ll note I was replying to comments about covering the machine while in operation, which is not necessary if the venting is working as intended.
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I know, and I did follow the posts. I read her commenting that she is hyper sensitive to smells, regardless of where they come from. That is an important issue for her to consider. Tooling with the ventilation may not solve her problem. Her clean room idea may be a more practical solution. Same with the allowing the pieces to air in the garage.
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I would stay away from owning a machine that burns stuff if I was overly sensitive to smells myself.
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I had a problem with smoke and smells for over a year. I taped up the connections, I sealed the venting window seams, I covered the lid with towels, the works.
Finally, someone suggested that maybe I had a leak in the ductwork itself. I couldn’t see any pinholes when I shined a light behind it and inside of it, but I wrapped the length of it in several layers of cling wrap, and ta-da! No more stink.
Except for extruded acrylic. My God, that stuff reeks for days. I eventually was given a choice between cutting mirrored acrylic or remaining married, so now I stick to wood and cast acrylic. 
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There is a lot of variabilities depending on the model of inline fan. they can move up to 800 cubic feet a minute (cfm) and while they would not reach that with a long exhaust, anything over 250 cfm going out the machine should do well. External fans are also much quieter than the exhaust fan on the machine. In any case, any holes up wind of the fan will have the air moving in, so only the hose from the fan to outside need be of concern.
The filters will do a good job as long as they are not clogged, but they clog amazingly fast, and the filter cost $250 to replace.
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Are you using a vent with the self closing louvers? With the stock “internal” fan, it takes very little obstruction to cause back pressure in your air flow. Even a light breeze blowing towards that side of your house can disrupt the flow.
I an external exhaust fan a couple of years ago and it has changed the level of odor and smoke released into the room. Keep in mind, for best results the fan should be the last thing the air flows through on its way to being vented. If placed anywhere else along the hose you are creating positive pressure in that pathway that will seek anywhere to release the pressure (crack, pinhole, loose connection)
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Hmmmm, mirrored acrylic…
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And I have never been able to eliminate the smell, despite over 4 years of trying. I can’t figure out where it’s coming from.
My only point is “your mileage may vary”. Some folks have gotten it perfect, and others not so much.
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We have a couple of these air quality monitors:
that we initially bought due to wildfires around California, and wanting to know what our local air quality was.
But I also found it really useful to diagnose, debug, and tweak various venting set ups.
I don’t think it would detect all air contaminants, but it can definitely measure smoke from plywood.
If you’re still struggling something like this might help measure when, how, and where smoke is getting into your space.
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One consideration – be sure the inline fan is at the exterior end of the run, so that it pulls exhaust through the hose rather than pushing. This keep the hose (along with its little holes and flaws) under negative pressure, just like the GF itself. Pushing creates positive pressure and will absolutely result in the stink you’re trying to avoid.
The forum has some excellent writeups on this – try searching for “exhaust” and user @PrintToLaser using the forum search tool (magnifier at upper right).
Good luck!
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Indeed! I also got an air quality monitor for my Glowforging area. One thing I found interesting about the resulting data: it did pick up on the time my tape had come loose and I was getting some smoke back into the room. Since I sealed it back up, I still smell some smoke during long cuts, but the air monitor doesn’t register a significant change in particulates. I also can’t see smoke anywhere, not even with my super-scientific method of turning the lights off and shining a laser pointer around.
I think this is because I’m very sensitive to smoke and it’s at a low enough level to probably be unimportant in terms of health effects. It gives me a little peace of mind to see that the numbers are good even if it’s bothering my nose.
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If at first you don’t succeed get a bigger hammer!
Not always the best advice but I did find a really big hammer in terms of filtering smoke and smells. At one point I was having a problem with smoke and smells and Glowforge had not yet delivered the first filter so I got this.
It is definitely a bigger hammer clearing out most of the house without even having a hose to it (the link has them cheapest on Amazon)
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And some people have a more sensitive sense of smell than others. I can smell my laser from elsewhere in the house. My husband can’t smell it when he’s standing a few feet away.
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One other thing to note is to be careful that other places in the home are not allowing the smoke to come in from outside. There have been many times someone left a window cracked that is near the room where the Glowforge is, and the smoke smell was coming BACK into the home. I try to check every time before I use it, but sometimes I forget. lol
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So, taking a look at this pic, are you saying that the top part of the in-line fan should go straight outside without any additional hose? Looking to also decrease smell in the room. Thanks!!
Ideally yes. Even better mount the fan outside of you can.
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As close as possible.
Just like the GF has gaps all around it but smoke doesnt(normally) come pouring out due to the fan pulling the air out the back, so too does physics work for the in-line fan. If there are holes or gaps in the line between the GF and the fan, the fan is pulling air into the hose so little smoke/smell should be escaping.
However, on the exit side of the fan, it’s being pushed instead. If there are holes(pin sized or smaller) or gaps in the joints, the smoke/smell will spill out of those. Even in minuscule amounts. You have a pretty short run so it’d be hard to make it much better.
How far does the hose extend outside?
Is that a sliding door that setup is sitting in?
Possibly is the hose dumping the smells into that area and it’s just seeping back in?
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This is how I finally ended up installing and so far so good! Tiny smell usually when opening lid. I do let fan run a long time after the project is done also. The fan is right at the wall going into a piece of duct work that goes to a dryer type vent outside. Built a shelf for the fan.
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It’s a sliding window in a regress window in a basement. So, there’s a cement well surrounding the area.
I don’t have it vented past the piece of wood it’s mounted on. Should the vent tube go past the window and extend outside?
If I vented it straight out and didn’t have it go up, if it would help with the smell while printing?
Should I have the tube go all the way up to above the wall? Worried about water, bugs, small animal crawling in…
THANKS!
I have the fan mounted at the duct work that goes outside if you look at picture. It looks like your fan is mounted going up the wall? I was told to have the fan as close as possible to the outside…only one hose, from the unit to the fan…then vents outside. If you are venting into a closed window well it could very well be trapping all of your smell? Mine vents to open air…a breeze takes it away from the house…you can smell it in the yard when working, but not in the house.
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