Ventilation woes

I’m trying really hard to build an air tight ventilation system that combines my 3d printer (which has an enclosure and AC infinity fan) and Glowforge together and spits the stuff outside. I tried having hand controlled blockers (a little sliding door mechanism) so that only the 3d printer or glowforge has the line (and the other side is blocked off), but the particular blockers I bought leak. Most of the smoke goes outside, but I still easily fill the basement and part of the ground floor with wood or plastic smells, and the family isn’t liking it :).

Does anybody else have good solutions / products for combining two (or more) fume producers?

If you have the Infinity fan after those blockers then they will leak in rather than leaking out :grin:


How long is your exhaust run?
Where in the run is the fan?
What type of window are you venting out of?
What kind of exhaust hose are you using and how are you sealing the connections?
(Ps - the little sliding door blockers are called blast gates :slight_smile: )

The exhaust only runs less than a foot through a y-joint to the outside (though eventually I’ll be wanting to go about 40 feet or so, so I would like to start thinking about that as well). I’m using AC infinity’s 4” hoses and then the metal circles with screws to tighten to secure them.

“Blast gates” - awesome! Thanks! Are there good quality ones that limit leakage? I’m willing to spend a fair bit to get this in good shape.

I’m also curious about good ways to detect leaks. I’m able to track leaks at 3pm when the sun is at the right angle through the window and I cut wood so it smokes well. Would love a better solution :).

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You can print one on your Glowforge if you have enough acrylic around. I’ve found it to be completely airtight.

You have decent hoses, that’s good. How much exhaust hose is there between the machines and Y joint?

For 40 feet you’ll definitely want more fans along the way, how many will depend on how many bends in your final run. (for reference, the internal GF fan is only recommended for 6’ of exhaust hose with max two 90 degree bends)

The DIY blast gate @dan84 linked is the most air tight one I’m aware of. I’m very happy with my Rockler blast gate but it’s at the very end of my run between the fan and window.

For checking for leaks, turn out the lights so it’s nice and dark then get out a flashlight or laser pointer while you run a job and you should be able to see the same kind of thing you’re spotting at 3 in the afternoon. You can also put soapy water along all the joints/run and look for bubbles but that can get messy.

If you don’t mind posting a pic of your setup we might be able to provide more suggestions.


I would love to find one of those fans built for 4" hose and have 600cpm airflow. So unless you have a stepped down 6" or 8" you are not moving enough air and would be losing smoke through the open areas of the Glowforge itself.

I have a Vivosun with 190cfm and when the Glowforge is cutting something smoky smoke goes everywhere. I have to use both the Glowforge exhaust and the Vivosun together where there is a lot of volume. If you have positive pressure anywhere the smoke will not make it to the window. Even wind blowing against the building can make the air go backward and smoke up the place, I have a louvered exhaust at the window that will keep the air from going backward even when there is no fan pushing it out.

That you are dividing the exhaust means that the volume you need is even more than my short single exit. The thing I have seen is that the more fan that you have the cleaner your Glowforge stays as the smoke does not stick around as long to get on to anything.

If your fan is bigger than ~500cfm and any places that might leak are on the other side of the fan from the window then any leaks will not get any smoke into the room, and might even start to remove any smoke already there.

For that, you will need a higher volume fan anyway. I think Infinity has a 1000cfm 8" fan that if it is near the window, and your current fan nearer the “Y” joint (but still pulling rather than pushing at the “Y” joint and well-sealed between the two fans you should have good airflow and no leakage that way.

Even yet when opening the Glowforge after a cut/engrave the material will still have a strong smell for a few days that only a room air purifier will help at all.

@marty1 Since this is not a technical support inquiry and outside our team’s scope I have moved this post to the Beyond the Manual so the discussion can continue there.

The biggest improvement will come from placing your fan(s) as near to the exterior of your house as possible and outside is even better. If your interior exhaust runs are all under negative pressure, you’ll never have an odor problem. If you are running positive pressure, you’ll fight this forever and a day.

Here’s my family-approved solution…


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