Adding an additional exhaust fan for longer run

I looked over past posts about adding an exhaust fan to help draw out fumes for various extended venting situations… but I cannot find an exact answer to if adding this secondary fan will place a burden on the GF fan and cause it to prematurely wear.

I saw various conflicting statements of the CFM rate of the GF fan, and conflicts on how to pair a secondary fan… some say match it… some say slightly under… some said slightly over the CFM of the GF

Can someone who know proper ventilation approaches suggest the right approach to adding a secondary exhaust fan?

I will be venting 5-10 feet across, then 5 feet up then 10 feet across to exterior flap vent.

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I run an extended exhaust run also. You want to place that booster as close as possible to the end of the run. At the exit of the structure is ideal. That way the extended run is under negative pressure, and no smoke is pushed out. Any of the run downstream of the booster is pressurized. I went ahead and sealed every joint in the galvanized 4" pipe just to be sure.
The booster would need to be at least 190 CFM. I’m no expert, but judging from my success that will do it for you. when I cut there is zero odor, and having the added purging air between operations is a cool bonus. :sunglasses:


Was it determined that the booster fan would not cause electrical issues by gyroing the Glowforge fan? I would love to be able to clear the air from the Glowforge longer than its own fan’s timing. I’m not sure why we don’t have the ability to run the internal fan longer.

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Yes, support answered that there are circuit protections against that.
I agree that the ability for the end user to configure the fan profile to fit their needs would be an improvement. Doesn’t matter in my case because a booster is required for my long exhaust run.

Like most of life, hindsight is clearer. Initially, the fans shut off just a few seconds after the end of the job. After customer input the company extended the runtime. Being able to push updates is a great innovation. One of the big strengths of a connected machine, along with support being able to remotely diagnose problems.


i do hope they continue to update that. i think we need a GFUI button that runs the fan for an extra 10-15 secs. that would allow people to run it a little more, if needed and on demand, to clear out fumes.


Or just leave it on until the lid is opened. Then the user gets to decide what it takes to exhaust to their satisfaction.

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anything at all that gives us control of how long it runs. i think it makes sense to have it time out, in case someone walks away and it just runs for hours (or all night). but some level of user control.

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Just running it for a set 10-15 sec even with an open lid would be handy for those fumes and wisps of smoke that hang out under cut pieces.

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We recommend ventilating your Glowforge as described in the user manual. If you take a different approach, I’m afraid we can’t provide support for that. Because this question is outside our team’s scope, I’ve moved it to the Beyond the Manual so the discussion can continue there.

It could probably be easily programmable with the minimum set ar today’s count. Would be extra cool to be able to set it by material and/or job.